From lee.stanford@eclipsys.com Tue Apr 22 19:24:21 1997 Received: by csres2.cropsci.ncsu.edu (5.61-AIX-1.2/1.0) from [192.41.32.161] with SMTP id AA117837 (for rdkeys, from lee.stanford@eclipsys.com/lee.stanford@eclipsys.com); Tue, 22 Apr 97 19:24:21 GMT Received: from smtp.eclipsnet.com ([199.250.158.26]) by eclipsys.com (8.8.5) id NAA18813; Tue, 22 Apr 1997 13:24:01 -0600 (MDT) From: lee.stanford@eclipsys.com X-Authentication-Warning: eclipsys.com: Host [199.250.158.26] claimed to be smtp.eclipsnet.com Received: from ccMail by smtp.eclipsnet.com (ccMail Link to SMTP R6.00.01) id AA861740800; Tue, 22 Apr 97 15:27:13 -0500 Message-Id: <9704228617.AA861740800@smtp.eclipsnet.com> X-Mailer: ccMail Link to SMTP R6.00.01 Date: Tue, 22 Apr 97 12:25:37 -0500 To: Subject: glowbug digests 11 - 15 Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="simple boundary" Status: O --simple boundary Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Attached files glowbugs digests 11 through 15 --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.011" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.011" GLOWBUGS Digest 11 Topics covered in this issue include: 1) Tube ID. by shiso@ici.net (Bruce Gavin /KD1MW) 2) GB: 6T9 xmtr by Jeffrey Herman 3) Identificationmarkings by p.holtham@mailbox.uq.oz.au 4) Re: Identificationmarkings by "Greg Parsons A.K.A. Rat" 5) Re: Identificationmarkings by Jeffrey Herman 6) Tubes free(almost) by dmedley@indirect.com (David Medley) 7) Re: identificationmarkings by MICHAEL@ecs.umass.edu 8) EASYTRAX drawing program. by The2X4@aol.com 9) GB- xtal protection / homebrew tubes by Duncan Cadd 10) Looking for a choke... by Greg Wasik 11) Re: Looking for a choke... by clarke@next3.acme.ist.ucf.edu (Thomas Clarke) 12) RE: GB- xtal protection by "Gable, Edward M" 13) Re: Looking for a choke... by pmills@cyberhouse.com (Phil Mills) 14) QRP by Conard Murray 15) RE: Looking for a choke... by "Gable, Edward M" 16) qrp...qro...voa? by cfm@tntech.edu 17) GB Transformer winding by thaake@bsm2ee1.attmail.com (thaake) 18) Re: Looking for a choke... by djw@unlinfo.unl.edu (Daniel Wright) 19) Re: Looking for a choke... by hawley@aries.scs.uiuc.edu (Chuck Hawley) 20) Re: Looking for a choke... by Jeffrey Herman 21) Transmitting Tubes by dmedley@indirect.com (David Medley) 22) Eimac Y514, ID by shiso@ici.net (Bruce Gavin /KD1MW) ---------------------------------------------------------------------- Date: Mon, 6 Nov 95 20:19:56 EST >From: shiso@ici.net (Bruce Gavin /KD1MW) To: glowbugs@theporch.com Subject: Tube ID. Message-ID: <9511070119.AA25446@ici.net> Can anybody ID a tube made by ITT, it's a 5948A, flange mount with wire lead-outs at base, has plate cap,total hight is arround 15 inches. ------------------------------ Date: Mon, 6 Nov 1995 17:00:23 -1000 >From: Jeffrey Herman To: Glowbugs List Subject: GB: 6T9 xmtr Message-ID: The 6T9 xmtr I mentioned before could possibly be classed as a "rock crusher". Someone else mentioned placing some resistance in series with the xtal to limit the voltage. Any suggestions as to what resistance one should start with? Jeff NH6IL ------------------------------ Date: Tue, 7 Nov 1995 14:22:42 +1000 >From: p.holtham@mailbox.uq.oz.au To: glowbugs@theporch.com Subject: Identificationmarkings Message-ID: My first post to the list - I hope I have done it right. I have a box of old tubes (valves) here, many of which have lost their identification markings. The markings seem to be some sort of white paint which is easily scratched off. Is their anything I can do to identify them or should they just go to the dump? I vaguely remember reading somewhere that the old markings could be enhanced/detected by spraying 'something' on to the glass, rather in the manner of dusting for finger prints I suppose, but it was a long time ago. Anyone got any ideas what the 'something' is, or is it just a case of faulty memory on my part? Cheers, Peter, VK4COZ ------------------------------ Date: Tue, 7 Nov 1995 00:02:29 +0500 >From: "Greg Parsons A.K.A. Rat" To: p.holtham@mailbox.uq.oz.au Cc: glowbugs@theporch.com Subject: Re: Identificationmarkings Message-ID: <9511070502.AA11424@galileo.mis.net> At 10:51 PM 11/6/95 -0600, you wrote: >My first post to the list - I hope I have done it right. > >I have a box of old tubes (valves) here, many of which have lost their >identification markings. The markings seem to be some sort of white paint >which is easily scratched off. Is their anything I can do to identify them >or should they just go to the dump? I vaguely remember reading somewhere >that the old markings could be enhanced/detected by spraying 'something' on >to the glass, rather in the manner of dusting for finger prints I suppose, >but it was a long time ago. > >Anyone got any ideas what the 'something' is, or is it just a case of >faulty memory on my part? > >Cheers, > >Peter, VK4COZ > > > > Peter, The way I find out what was on the valve/tube is to breath on it and fog it, like you would a mirror, then look at it, sometimes, but not always, you can read what was there at one time. hope this helps you out. 73, Greg KE4OOO ------------------------------ Date: Mon, 6 Nov 1995 19:08:55 -1000 >From: Jeffrey Herman To: p.holtham@mailbox.uq.oz.au Subject: Re: Identificationmarkings Message-ID: Placing them in the refrigerator was supposed to help - apparently the residue left on the tube where the markings were will not frost up but the rest of the tube will. Any other suggestions? Jeff NH6IL ------------------------------ Date: Mon, 6 Nov 1995 23:09:36 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: Tubes free(almost) Message-ID: <199511070609.XAA05112@ns2.indirect.com> This is a composite of something I posted on rec.radio.swap I never get much response from that news group. Anyway I have tried unsuccessfully to dispose of these tubes so rather than take them to the landfill I will donate them to anyone who has a real use for them. All I will ask is to have my out of pocket expenses covered. 1. 2 811A tubes. One is made in the USSR but carries the Raytheon label. The other is made in the USA. I have no idea of their condition except that their filaments are OK. They look unused. 2. 8 829B tubes. 4 of these are Amperex in their original boxes, 1 is an RCA also in a box and there are 3 unboxed ones. At someone's suggestion I called AES who offered me $1.25 which I respectfully declined. I would rather give them to someone who can use them. Finally if there is anyone out there who collects transmitting tubes I have a few strange ones with no apparent use except for display. Reply dmedley@indirect.com ------------------------------ Date: Tue, 07 Nov 1995 09:17:50 -0500 >From: MICHAEL@ecs.umass.edu To: GLOWBUGS@THEPORCH.COM Subject: Re: identificationmarkings Message-ID: <01HXCUHSBEWYAW22KG@ECS.UMASS.EDU> >that the old markings could be enhanced/detected by spraying 'something' on >to the glass, rather in the manner of dusting for finger prints I suppose, >but it was a long time ago. >Anyone got any ideas what the 'something' is, or is it just a case of >faulty memory on my part? I've forwarded to Peter some of the helpful responses I got from the BA group when I asked this question back in August. John Michael michael@ecs.umass.edu ------------------------------ Date: Tue, 7 Nov 1995 09:39:29 -0500 >From: The2X4@aol.com To: glowbugs@theporch.com Subject: EASYTRAX drawing program. Message-ID: <951107093928_15118903@emout04.mail.aol.com> Hello hello. Two users logged on and got the program last night. Joe and Robert. Please return comments about it to us if you will, gentlemen. The time slot last night worked fine for me. It was apparently not convenient for others. I will change the time slot for today. The program will be available from 6PM CST til 10PM this evening. Thats 11/07/95 6PM CST until 10PM. The # here is (615) 847-9704. It will take 6 to 7 minutes to transfer at 14.4. BTW: Mike did you get the program running? Carl The2x4 ------------------------------ Date: Tue, 7 Nov 1995 15:42:09 +0100 (MET) >From: Duncan Cadd To: glowbugs@theporch.com Cc: dcadd@luc.ac.be Subject: GB- xtal protection / homebrew tubes Message-ID: <9511071442.AA18341@alpha.luc.ac.be> Greetings, Folks, from a dull, cold and dry Diepenbeek in N.E. Belgium! Jeff, I recall reading on the BA list ages ago that the thing to do is stick a 6V 60mA bulb in series with the crystal to reduce the chance of it fracturing - I think in Colonial parlance this is a type #47 lamp but don't take my word for it, I'm going from memory. The subject of homebrew tubes comes up from time to time. If anyone ever does this, they may find Goodfellow Metals useful to know. They DO have a US site, Goodfellow Corp. Berwyn, PA, but the UK cat doesn't give address details, so if interested you'll need to contact the UK general enquiries desk. Email details follow: ***ALL UK BASED*** Catalogue sales: sales@goodfellow.com Technical enquiries: tech@goodfellow.com General enquiries: enq@goodfellow.com (this one to ask for cat) So what are they good for ? Examples: cat # PT005103 0.002mm Wollaston wire (platinum with a silver sheath which you etch off with 10% nitric acid to leave a 0.002mm wire) 10cm 110 UK pounds - what used for - 1910/1920 vintage electrolytic detectors (see Lindsay's reprint of H.W. Secor's "The How and Why of Radio Apparatus) and also the "thermal telephone" (same ref!) Maybe interesting for the restorer/museum curator (or wealthy ham!) FE045400 1mm Kovar wire 5m long 35.4 UK pounds used for metal/glass seals W145300 1% Thoriated tungsten wire diam 0.125mm 10m long 39.8 UK pounds used for valve filaments!!! Plus LOADS of other goodies. VISA, Mastercard & Eurocard accepted. If interested, you might want to contact these people. No minimum order and carriage etc included in price. VAT to be paid in UK and EU. Usual disclaimers. 73, Duncan ON9CHU / G0UTY G-QRP 8117 ------------------------------ Date: Tue, 07 Nov 1995 11:00:38 -0500 (EST) >From: Greg Wasik To: glowbugs@theporch.com Subject: Looking for a choke... Message-ID: --Boundary (ID aKIk5dl0fM7YMOUi7zyUMg) Content-type: TEXT/PLAIN Greetings everyone. This forum is really what ham radio should be... building and experimenting with stuff that glows in the dark. Anyway, I have an amplifier project that I am slowly acquiring parts for. I am working on the power supply right now. I have a pole transformer that gives me 3900 volts rms with a 240 input. I want to end up with 3800 volts at a couple of amps to provide for a pair of 8877s. The 8877s are low voltage guys and 4 KV is the max rating of plate voltage. So I am thinking of a choke input filter after the rectumfiers. This should give me ~.9 x 3900(rms AC) =3500 which is just about what I need. So does anyone know of a source or supply for a choke that is 2H at 2A and rated for 4 KV? I would rather go this route than use large variacs on the primary and a capacitive input filter. Greg KD1PL --Boundary (ID aKIk5dl0fM7YMOUi7zyUMg)-- ------------------------------ Date: Mon, 7 Nov 94 12:24:29 EST >From: clarke@next3.acme.ist.ucf.edu (Thomas Clarke) To: glowbugs@theporch.com Subject: Re: Looking for a choke... Message-ID: <9411071724.AA06413@next3.acme.ist.ucf.edu> >I want to end up with 3800 volts at >a couple of amps to provide for a pair of 8877s I thought this was a QRP list :-) What's this for? RF induction heating? > a choke that is 2H at 2A and rated for 4 KV Two henries is good for 2A, but if you are doing other than CW, the voltage will rise when the supply current drops. You might need a larger choke for the lower currents or a swinging choke. At any rate Fair radio has a 2H at 1.6Amp choke for $25 (55 lbs) Tom Clarke KE4VFH ------------------------------ Date: Tue, 07 Nov 95 11:56:00 EST >From: "Gable, Edward M" To: glowbugs Subject: RE: GB- xtal protection Message-ID: <309F9DFF@smtpgate.rfc.comm.harris.com> Jeff, I recall reading on the BA list ages ago that the thing to do is stick a 6V 60mA bulb in series with the crystal to reduce the chance of it fracturing - I think in Colonial parlance this is a type #47 lamp but don't take my word for it, I'm going from memory. +++++++++ Duncan - Your close, but here in the Colonies the type 47 is 6-9V @ .15 Amp. The only .06 A variety are the type 48 (screw base) and type 49 (bayonet base), both rated at 2.0 volts. Now, aren't you glad I cleared that right up - HiHi. I've seen type 47's used but the 48/49 seem more sensitive. Cheerio, 73 Ed K2MP emg@rfc.comm.harris.com Near Rochester ------------------------------ Date: Tue, 7 Nov 1995 11:18:01 -0600 >From: pmills@cyberhouse.com (Phil Mills) To: glowbugs@theporch.com Subject: Re: Looking for a choke... Message-ID: <199511071718.LAA13450@ns.cyberhouse.com> I thought 8 KW was QRP..... thanks, Phil >>I want to end up with 3800 volts at >>a couple of amps to provide for a pair of 8877s > >I thought this was a QRP list :-) >What's this for? RF induction heating? > Phil Mills, AB5TH pmills@cyberhouse.com 713-482-2763 ------------------------------ Date: Tue, 07 Nov 1995 11:22:15 +0600 >From: Conard Murray To: glowbugs@theporch.com Subject: QRP Message-ID: <01HXCYXUF9RMI1BQ5V@tntech.edu> > I thought this was a QRP list :-) > What's this for? RF induction heating? > I don't want to confine the list to just QRP. I think that new construction using firebottles is enough. 73 all de Conard ws4s Conard Murray, WS4S * Microcomputer Support Specialist 217 Dyer Avenue * D. W. Mattson Computer Center Cookeville, TN 38501 * Clement Hall 227B 615-526-4093 * 372-3982 *********************************************************** Firebottle Junkie and Glowbugs listkeeper cfm@tntech.edu (work) ws4s@midtenn.net (home) ------------------------------ Date: Tue, 07 Nov 95 12:15:00 EST >From: "Gable, Edward M" To: glowbugs Subject: RE: Looking for a choke... Message-ID: <309FA407@smtpgate.rfc.comm.harris.com> Greg wrote: >Greetings everyone. This forum is really what ham radio should be... >building and experimenting with stuff that glows in the dark. >Anyway, I have an amplifier project --- I want to end up with 3800 volts at >a couple of amps to provide for a pair of 8877s. +++++++++ Sorry Greg - 8877's don't glow . Let's see now; 3800Vx2A=7600W input at a modest 55% efficiency = 4180W output. "Hello, can you hear me now" Gee, ya should go with a pair of 4-1000's, now THEY glow! Good luck with your project - I'll see (no, hear) you in the pile ups. 73, Ed K2MP ------------------------------ Date: Tue, 07 Nov 1995 11:49:04 +0600 >From: cfm@tntech.edu To: glowbugs@theporch.com Subject: qrp...qro...voa? Message-ID: <01HXCZUQAUCYI1CGMZ@tntech.edu> OK...I wasn't looking too close at that one...I guess we do need to keep this stuff legal ;-) 73 de conard Conard Murray, WS4S * Microcomputer Support Specialist 217 Dyer Avenue * D. W. Mattson Computer Center Cookeville, TN 38501 * Tennessee Tech University 615-526-4093 * 372-3982 voice 372-6172 fax *********************************************************** Firebottle Junkie and Glowbugs listkeeper cfm@tntech.edu (work) ws4s@midtenn.net (home) ------------------------------ Date: Tue, 07 Nov 1995 12:18:32 -0600 >From: thaake@bsm2ee1.attmail.com (thaake) To: glowbugs@theporch.com Subject: GB Transformer winding Message-ID: Bugites, I have been collecting information on the building of transformers and have some specifics on the "disassembly" of transformers. The cost is a SASE. I'd rather send it in the mail versus discussing it here since there is other valuable info in the print that you may also want. I haven't tried the method the article describes which is burning the entire core. I have successfully disassembled power transformer cores in my kitchen oven but have refrained from doing it very often because of the stink. Maybe burning it has some merit. Anyway my method works and I am sure the article describes at least an equally acceptable way. BTW, the article is a start to finish discussion with examples and pictures. Tim Haake 128 Lakepoint Drive St. Peters, MO 63376 Tim WA0TSY thaake@bsm2ee1.attmail.com ------------------------------ Date: Tue, 7 Nov 95 12:45:05 CST >From: djw@unlinfo.unl.edu (Daniel Wright) To: glowbugs@theporch.com Subject: Re: Looking for a choke... Message-ID: <9511071845.AA00258@unlinfo2.unl.edu> >I thought 8 KW was QRP..... > >thanks, >Phil There's a very fine fellow who haunts these electronic environs who told me the FCC rules state that "the minimum power required to make contact is always equal to the maximum power available"....or some such..(;>.. dan ..WA0JRD and djw@unlinfo.unl.edu ------------------------------ Date: Tue, 7 Nov 1995 12:49:33 -0600 (CST) >From: hawley@aries.scs.uiuc.edu (Chuck Hawley) To: clarke@next3.acme.ist.ucf.edu Cc: glowbugs@theporch.com Subject: Re: Looking for a choke... Message-ID: <199511071849.MAA23796@aries.scs.uiuc.edu> > > >I want to end up with 3800 volts at > >a couple of amps to provide for a pair of 8877s > > I thought this was a QRP list :-) > What's this for? RF induction heating? > > > a choke that is 2H at 2A and rated for 4 KV > > Two henries is good for 2A, but if you are doing other > than CW, the voltage will rise when the supply current > drops. You might need a larger choke for the lower currents > or a swinging choke. > > At any rate Fair radio has a 2H at 1.6Amp choke for $25 > (55 lbs) > > > Tom Clarke > KE4VFH > What you can do is tune the choke....put a capacitor across the choke which makes the parallel combination a high impedance at 120 Hertz. The charging of the storage capacitor is limited by the high impedance during low current draw, and the voltage across the storage cap will stay near the average charging voltage instead of charging up to peak. When current is drawn, the choke inductance will go down, detuning the near resonance parallel combo, and allowing the cap to charge from the low impedance of the diode bridge and the now untuned choke. Stay on the side of resonance that will not allow the parallel combo to go thru resonance (highest impedance) as the choke inductance goes down as higher current is drawn. The choke does not have to be a swinging choke, a regular choke will change (lower) inductance enough to produce the desired effect. Look at power supplies by Henry (no pun intended) and Collins (516F-2 800 Volt supply is a good example). 2*pi*f equals one over the square root of L*C.....by the way. 73. Chuck, KE9UW ------------------------------ Date: Tue, 7 Nov 1995 09:49:54 -1000 >From: Jeffrey Herman To: Phil Mills Subject: Re: Looking for a choke... Message-ID: Maybe QROp or QRPo? In any respect, I hope we can encourage building with tubes no matter what the input power will be. Jeff NH6IL On Tue, 7 Nov 1995, Phil Mills wrote: > I thought 8 KW was QRP..... > > thanks, > Phil > > >>I want to end up with 3800 volts at > >>a couple of amps to provide for a pair of 8877s > > > >I thought this was a QRP list :-) > >What's this for? RF induction heating? > > > Phil Mills, AB5TH > pmills@cyberhouse.com > 713-482-2763 > > ------------------------------ Date: Tue, 7 Nov 1995 15:05:30 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: Transmitting Tubes Message-ID: <199511072205.PAA27823@ns2.indirect.com> Here is the promised list of transmitting and misc. tubes 1. In boxes probably good except where noted. 2E26,6AS7,4X150A,46(3),6HF5(3),812A,813 (suspect),872A(2),CHY1616(2) 2. Unboxed 4X150A(4),RK60(2),4C35(4),4E27,Eimac 100TH (2 1 suspect),HY114B,572B(suspect),UV203A,802,808,807,815(2),828,715B,8165(Eimac) ,810(suspect),872A(2),836,CUE 38111A,CL1006,CWL327A,866A(2),1616,8003,8025 The way I would like to handle this is to ask first if anyone has a specific need for any of these tubes as spares for an existing unit or for an HB project. I will negotiate a nominal price with respondents directly. The tubes that are marked suspect are freebies. Some of these tubes must be worth something to someone. The 829B/811A freebies went quickly to many different respondents. I tried to be fair to all who replied. Reply directly to dmedley@indirect.com ------------------------------ Date: Tue, 7 Nov 95 18:43:05 EST >From: shiso@ici.net (Bruce Gavin /KD1MW) To: glowbugs@theporch.com Subject: Eimac Y514, ID Message-ID: <9511072343.AA08628@ici.net> I am looking for ID and basic opperating characteristics for the Eimac Y514 tube. Got a pair of these tubes with sockets out of some sort of industrial high voltage power supply and wondering about pressing them into RF service. Thanks; Bruce ------------------------------ End of GLOWBUGS Digest 11 ************************* --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.012" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.012" GLOWBUGS Digest 12 Topics covered in this issue include: 1) Re: Looking for a choke... by Bill Turner 2) NEED: Heathkit Manual for MR-11 by "Gary H. Harmon, Jr." 3) Re: EASYTRAX drawing program. by mont@netcom.com (Mont Pierce) 4) EASYTRAX drawing program by The2X4@aol.com 5) FS: Heathkit SB-100 by "Gary H. Harmon, Jr." 6) TEKTRONIC LIST MAILED by David Stinson <72227.1640@compuserve.com> 7) 6HF5 tubes by dmedley@mail.hvs.com 8) 811A tubes by dmedley@mail.hvs.com 9) Re: 6HF5 tubes by Dave Hockaday 10) Power Transformers by "Tony Stalls (K4KYO)" 11) Re: EASYTRAX drawing program. by steve@hi.com (Steve Byan) 12) Re: Looking for a choke... by Greg Wasik 13) GLOWBUGS (great book for simple toob plans) by Stan Skelton 14) Attention All Canadians (eh?) by Stan Skelton 15) GB 6L6 sub (was great book for simple toob plans) by mjsilva@ix.netcom.com (michael silva) 16) sp-200 power supply needed by HAMRLUND@aol.com 17) Re: GB 6L6 sub (was great book for simple toob plans) by pmills@cyberhouse.com (Phil Mills) 18) want to locate rack mount kit for HRO-500 by HAMRLUND@aol.com 19) Re: QRP by "Tony Stalls (K4KYO)" ---------------------------------------------------------------------- Date: Tue, 07 Nov 1995 19:55:01 -0800 >From: Bill Turner To: greg@willie.nl.nuwc.navy.mil, Subject: Re: Looking for a choke... Message-ID: <199511080355.TAA18771@mail.eskimo.com> At 10:02 AM 11/7/95 -0600, Greg Wasik wrote: -snip- >which is just about what I need. So does anyone know of a source or supply for >a choke that is 2H at 2A and rated for 4 KV? I would rather go this route than >use large variacs on the primary and a capacitive input filter. > --------------------------------------------------------------- A word of caution -- maybe you've already thought about this, but just in case... Choke input filters are rarely used in amplifiers for SSB, due to their tendency to try to maintain current flow at a constant level. With the rapidly varying current drain of an SSB signal, a capacitor-only filter works very well and eliminates the "inductive kick" problem. Two henries is not a lot of inductance, so the problem shouldn't be TOO large, but on the other hand, why have it at all? Personally, I'd go with the variac and the capacitor input. 73, Bill W7LZP wrt@eskimo.com ------------------------------ Date: Tue, 7 Nov 1995 22:18:43 -0600 >From: "Gary H. Harmon, Jr." To: glowbugs@theporch.com Subject: NEED: Heathkit Manual for MR-11 Message-ID: <9511080418.AA13394@legend> Am I the only person with one of these radios? It's a MR-11 Mariner DF receiver. None of the manual places have it in stock. Heath wants $40 for a copy! NOT!!! Anyone have one? Please let me know. 73, GARY ======================================================================== Gary H. Harmon, Jr., K5JWK gharmon@txdirect.net 6302 Robin Forest K5JWK@K3WGF.STX.USA.NOAM San Antonio, TX 78239 ------------------------------ Date: Tue, 7 Nov 1995 21:21:10 -0800 (PST) >From: mont@netcom.com (Mont Pierce) To: The2X4@aol.com Cc: glowbugs@theporch.com Subject: Re: EASYTRAX drawing program. Message-ID: <199511080521.VAA22427@netcom15.netcom.com> > The time slot last night worked fine for me. It was apparently not > convenient for others. I will change the time slot for today. > > The program will be available from 6PM CST til 10PM this evening. > Thats 11/07/95 6PM CST until 10PM. > The # here is (615) 847-9704. It will take 6 to 7 minutes to transfer at > 14.4. For me it's not the timeslot that's inconvenient, it's the mode. Can someone please post easytrax to an ftp site? tnx & 73, de km6wt -- Mont Pierce +-------------------------------------------------------------------------+ | Ham Call: KM6WT Internet: mont@netcom.com | | bands: 80/40/20/15/10/2 | | modes: cw,ssb,fm | +-------------------------------------------------------------------------+ ------------------------------ Date: Wed, 8 Nov 1995 00:32:32 -0500 >From: The2X4@aol.com To: glowbugs@theporch.com Subject: EASYTRAX drawing program Message-ID: <951108003231_82144493@emout05.mail.aol.com> Glad to see a few more got the program this evening. I have the program on my main BBS but it is 2400 baud. Takes a long time that way. Call me at (615) 847-9704. I'll set this system up on host mode at 14.4 on a per request basis. That takes about 6 minutes to download. I suggest you wait for comments on how others view the program. I am sold on EASYTRAX as a standard. In fact I'm already making a few tube symbols for my own use. Started with the 6146. I'm also checking on MAC compatibility. BTW: Easyplot, the printing program for EASYTRAX , has HP plotter file output. That may provide a degree of compatibility for MAC users. Still it doesn't provide the interactivity PC users would have. Also EASYTRAX has a manual that can be printed out for quick reference. Carl ------------------------------ Date: Wed, 8 Nov 1995 06:27:49 -0600 >From: "Gary H. Harmon, Jr." To: glowbugs@theporch.com Subject: FS: Heathkit SB-100 Message-ID: <9511081227.AA20774@legend> Exceptional SB-100 HF transceiver with HP-23 AC supply, HS-24 speaker, desk mike, and manuals. $200. Trades considered. Drop me a line if interested. If necessary, you can call me at (210) 657-1549 after 6PM CST. Thanks and 73, GARY ======================================================================== Gary H. Harmon, Jr., K5JWK gharmon@txdirect.net 6302 Robin Forest K5JWK@K3WGF.STX.USA.NOAM San Antonio, TX 78239 ------------------------------ Date: 08 Nov 95 08:26:11 EST >From: David Stinson <72227.1640@compuserve.com> To: mailing list Cc: mailing list Subject: TEKTRONIC LIST MAILED Message-ID: <951108132611_72227.1640_EHM79-1@CompuServe.COM> I finally finished the Tektronic pieces-parts list and mailed it to the people who wrote. There are no plug-ins, CRTs or tubes on the list. Just probes, accessories, test jigs and etc. If you want the listing, please email me. Please do not post back to the mailing list. TNX DE Dave AB5S/7 72227.1640@compuserve.com ------------------------------ Date: Mon, 6 Nov 1995 17:04:54 +0500 >From: dmedley@mail.hvs.com To: glowbugs@theporch.com Subject: 6HF5 tubes Message-ID: <199511081337.GAA19135@bud.indirect.com> These are sweep tubes I believe but are they useful for anything else? I know some rice boxes used sweep tubes but I don't know if these are applicable. Anyone interested? Anyone want them? Reply dmedley@indirect.com ------------------------------ Date: Mon, 6 Nov 1995 17:10:54 +0500 >From: dmedley@mail.hvs.com To: glowbugs@theporch.com Subject: 811A tubes Message-ID: <199511081338.GAA19173@bud.indirect.com> I have 2 811A tubes looking for a home. One is made in the USSR but has the Raytheon name the other is US made. Both have good filaments and that is all I can tell you. I will donate these to someone who has a real use for them and is willing to take the risk that they are no good. They look fine. Reply dmedley@indirect.com ------------------------------ Date: Wed, 8 Nov 95 09:23:33 EST >From: Dave Hockaday To: glowbugs@theporch.com Subject: Re: 6HF5 tubes Message-ID: <9511081423.AA05510@merlin.nando.net> At 07:40 AM 11/8/95 -0600, you wrote: >These are sweep tubes I believe but are they useful for anything else? >I know some rice boxes used sweep tubes but I don't know if these are >applicable. Anyone interested? Anyone want them? These were used in several models of the WRL Galaxy transceivers. I owned the Galaxy III, V, and V mk3. They all used a pair of the 6HF5's in the PA. 73 de WB4IUY ------------------------------ Date: Wed, 8 Nov 1995 09:45:29 -0500 (EST) >From: "Tony Stalls (K4KYO)" To: GLOWBUGS Subject: Power Transformers Message-ID: A couple of my several tube projects are being held up by power supplies, thanks to my not being able to find appropriate power transformers and filter chokes. Supply #1 needs to put out 560 VDC @ 250 ma., 105 VDC @ 50 ma. and supply #2 needs 1000 VDC @ 350 ma. There is a surplus AC supply, the PP-327, that will satisfy the latter need if anybody happens to have those fairly rare jewels. 73, Tony K4KYO ------------------------------ Date: Wed, 8 Nov 1995 10:14:41 -0400 >From: steve@hi.com (Steve Byan) To: glowbugs@theporch.com Subject: Re: EASYTRAX drawing program. Message-ID: >For me it's not the timeslot that's inconvenient, it's the mode. Can >someone please post easytrax to an ftp site? Easytrax is available from any SimTel mirror, such as oak.oakland.edu, in the SimTel/msdos/cad/easytrax.zip. Also available through the web at http://www.acs.oakland.edu/oak/ Steve Byan internet: steve@hi.com Hitachi Computer Products (America), Inc. 1601 Trapelo Road phone: (617) 890-0444 Waltham, MA 02154 FAX: (617) 890-4998 ------------------------------ Date: Wed, 8 Nov 95 10:55:04 EST >From: Greg Wasik To: wrt@eskimo.com, glowbugs@theporch.com Subject: Re: Looking for a choke... Message-ID: >At 10:02 AM 11/7/95 -0600, Greg Wasik wrote: >-snip- >>which is just about what I need. So does anyone know of a source or supply >for >>a choke that is 2H at 2A and rated for 4 KV? I would rather go this route than >>use large variacs on the primary and a capacitive input filter. >> >--------------------------------------------------------------- >A word of caution -- maybe you've already thought about this, but just in >case... >Choke input filters are rarely used in amplifiers for SSB, due to their >tendency to try to maintain current flow at a constant level. With the >rapidly varying current drain of an SSB signal, a capacitor-only filter >works very well and eliminates the "inductive kick" problem. Two henries is >not a lot of inductance, so the problem shouldn't be TOO large, but on the >other hand, why have it at all? Personally, I'd go with the variac and the >capacitor input. > >73, Bill W7LZP >wrt@eskimo.com > Bill After doing some reading of the responses here and pondering the meaning of life, I now have second thoughts about the choke input filter approach. In order to prevent achieving the peak transformer voltage (1.41 Erms) I must maintain a critical inductance of Rl/1000 where Rl is the load resistance. If I maintain an inductance above the critical inductance I will always be close to Edc the average value (.9 rms) -which I desire as to not exceed the 4 KV rating of the 8877s. So I really need a much larger inductor and worst case is = (plate voltage/idling current)/1000 which might be closer to 20H !!! This might be a bit difficult to find something that large and at that current rating. Perhaps you are right Bill I am thinking about going back to the cap input approach. Hmmm... Anyone know of a source for a large variac??? Thanks for all the previous comments... Greg KD1PL ------------------------------ Date: Wed, 8 Nov 1995 08:47:53 -0800 (PST) >From: Stan Skelton To: glowbugs list Subject: GLOWBUGS (great book for simple toob plans) Message-ID: Hi all...I have found a treasure trove of great tube ideas, plans and building instructions for relatively easy tube projects. It is called "101 EASY HAM RADIO PROJECTS" by Robert M. Brown & Tom Kneitel, published by Howard W. Sams & Co. Inc. / The Bobbs-Merrill Co. Inc. 1968 & 1970 Library of Congress # 68-58088. A partial list of tube projects is: One tube 40 meter Transmitter (6JE8) 20 meter ssb final amp (811A) 400W TVI-Free amplifyer (813) mike mixer (12AT7) simple plug in VFO (6AK6) tunable audio filter (12DT7) 160 meter VFO (6AK6 & 6V6) 8-Watts on 160 thru-40 meters (5881) tx two tube electronic CW keyer (2X (6SN7)) and many many more (some plans are also included for those funny 3 legged things too)..... TtFn...Stan VE7SKT..(use glowbugs in subject line) ------------------------------ Date: Wed, 8 Nov 1995 13:11:50 -0800 (PST) >From: Stan Skelton To: glowbugs list Cc: qrp maillist Subject: Attention All Canadians (eh?) Message-ID: Hey all Canadians.....listen up eh?...I've seen several postings requesting info on purchasing electronics supplies easily available from Canada..... All Electronics Corp....sells mercury wetted reed relays, terminals, toroids, transistors, transformers etc. etc. etc. BEST OF ALL their 1-800 826-5432 number works in Canada! I've just ordered a catalogue and they seemed pleased to send my one here in BC and said they often ship to Canada! Neat O! 73's Stan...VE7SKT ------------------------------ Date: Wed, 8 Nov 1995 11:23:21 -0800 >From: mjsilva@ix.netcom.com (michael silva) To: glowbugs@theporch.com Subject: GB 6L6 sub (was great book for simple toob plans) Message-ID: <199511081923.LAA15303@ix3.ix.netcom.com> Stan VE7SKT wrote: >.... > 8-Watts on 160 thru-40 meters (5881) tx >.... I've just been reading over on rec.audio.tubes that the 5881 (new ones made by Sovtek) is a very rugged industrial-type 6L6, and that AES sells them for about $8. The conventional wisdom, BTW, is that Russian tubes are pretty decent, but the Chinese ones are a joke. 73, Mike, KK6GM ------------------------------ Date: Wed, 8 Nov 1995 17:52:45 -0500 >From: HAMRLUND@aol.com To: GLOWBUGS@theporch.com Subject: sp-200 power supply needed Message-ID: <951108175241_101511399@emout05.mail.aol.com> **Posting this for a friend working with juviniles** Helping kids learn more about ham radio. i donated an sp-200 reciever. and now he needs a power supply for it. any help i.e. a complete supply, or transformers ect. would be of great help to him. if you have such an animal, and would like to help out a bunch of kids to have fun, learn about ham radio, and stay out of trouble, Please call Ben at 517-769-6493 after 6:30pm est please no calls after 9 pm est (he has a new born & sleep is presious) anything you can do would be appreciated. if you have other things, working or not, and want to know they're going to a good cause, give Ben a call. Thank you for your time. I can deliver messages as Ben is a local call for me, but prefer you deal with him. his call is KG8SX. ------------------------------ Date: Wed, 8 Nov 1995 17:07:27 -0600 >From: pmills@cyberhouse.com (Phil Mills) To: mjsilva@ix.netcom.com Cc: glowbugs@theporch.com Subject: Re: GB 6L6 sub (was great book for simple toob plans) Message-ID: <199511082307.RAA18642@ns.cyberhouse.com> I bought a set of Chinese 811A's from RF Parts Company that were great....but then RF Parts also guarenteed them.... thanks, Phil >Stan VE7SKT wrote: >>.... >> 8-Watts on 160 thru-40 meters (5881) tx >>.... > >I've just been reading over on rec.audio.tubes that the 5881 (new ones >made by Sovtek) is a very rugged industrial-type 6L6, and that AES >sells them for about $8. The conventional wisdom, BTW, is that Russian >tubes are pretty decent, but the Chinese ones are a joke. > >73, >Mike, KK6GM > > Phil Mills, AB5TH pmills@cyberhouse.com 713-482-2763 ------------------------------ Date: Wed, 8 Nov 1995 18:47:55 -0500 >From: HAMRLUND@aol.com To: GLOWBUGS@theporch.com Subject: want to locate rack mount kit for HRO-500 Message-ID: <951108184755_16754289@emout06.mail.aol.com> would like to find the rack mount adapter kit for the National HRO-500 reciever. also, first time i've had one of these, they're beautiful and function very nicely. thanks robert ------------------------------ Date: Wed, 8 Nov 1995 18:49:49 -0500 (EST) >From: "Tony Stalls (K4KYO)" To: Multiple recipients of list Subject: Re: QRP Message-ID: On Tue, 7 Nov 1995, Conard Murray wrote: > > > I thought this was a QRP list :-) > > What's this for? RF induction heating? > > > I don't want to confine the list to just QRP. I think that new > construction using firebottles is enough. > 73 all de Conard ws4s You can subscribe to the QRP list by sending a message to listserv@lehigh.edu with the text: subscribe qrp-l [your name] [your call] If QRP is your thing, then that list is a must. All kinds of QRP construction is discussed there, including tube-type rigs. ------------------------------ End of GLOWBUGS Digest 12 *************************  --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.013" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.013" GLOWBUGS Digest 13 Topics covered in this issue include: 1) GB:Pre-Tube Technology by joe@westonia.com (Joseph Cooper) 2) Re: Looking for a choke... by Kevin J Pease 3) Re: Looking for a choke... by ralph.hartwell@emachine.com (Ralph Hartwell) 4) A Raytheon USSR-made tube? by Jeffrey Herman 5) filter caps by Bruce Robertson 6) Re: filter caps by weinfurtner@ouvaxa.cats.ohiou.edu (Greg Weinfurtner) 7) RE: filter caps by "Gable, Edward M" 8) Re: filter caps by torell@sicom.com (Kent Torell) 9) Re: filter caps by MODSTEPH@ACS.EKU.EDU 10) RE: filter caps by Paul_Bocci-CPB007@email.mot.com 11) "TWIST LOK" TYPE MULTI-SECTION ELECTROLYTIC CAPCITORS! by Wai Kei Leung 12) National NC-140 parts by Jim Clark 13) Auto Radio Tubes FS by dmedley@indirect.com (David Medley) ---------------------------------------------------------------------- Date: Wed, 8 Nov 95 19:11 EST >From: joe@westonia.com (Joseph Cooper) To: glowbugs@theporch.com Subject: GB:Pre-Tube Technology Message-ID: I just got in my current issue of the Xtal Set Society Newsletter, and I throught I do a little plug for the organization. This months issue's main article is on a 'Grounded Loop' xtal set, which has many of the characteristics of the grounded grid amplifier of tube fame. Its a simple little thing that uses a loop antenna from an old AM radio (I pick them up for $1.00 at our local surplus store) and 360 uuf tuning cap. As with most loop antenna's, you have two coils; the small pickup and the larger tuning coil. The two coils are run in series with the small coil being connected to the antenna. At the point where the small coil is connected to the larger it is grounded. The larger coil is then place in parallel with the tuning cap and then the xtal is connnected. From there it goes off to either your head phones or an audio amp. The curcuit is thus: Ant....L1........L2.......X......HPhone... I I I I I G C1 C2 G G Where L1 small loop L2 Large Loop C1 365 uuf tuning cap C2 .002 uf fixed cap G Grounds There is also a great article on how to match impedence across a curcuit (eg from antenna to input coil) and other bits an pieces. I've built several xtal sets based on their designs and have had some great fun with them. If you are interested it's only $9.95 per year for the bi-monthly newsletter (about 8 pages) and they are at P.O. Box 3026 St. Louis Mo 63130 And the usual disclamer about me having no monitary interest in the organization blah de blah blah.. '73s =================================================================== * Joseph Cooper-VE3FMQ QTH-East York-near Toronto Ontario Canada * * Interests are:-Lowfer/VLF/BCB Radio-Woodworking-Steam Railroads * * -Nikola Tesla-Antique Radios-Crystal Radios-Travel-Burmese Cats * * FAX (416) 423-7782 9:00pm to 5:00pm EDST Monday To Friday Only * =================================================================== ------------------------------ Date: Wed, 8 Nov 1995 20:25:57 -0600 (CST) >From: Kevin J Pease To: Greg Wasik Subject: Re: Looking for a choke... Message-ID: You should look around for a large Swinging Choke. The swinging choke is designed to compensate for varrying load by changing inductance with changing current. They do that by saturating their core at higher currents thus lowering core permiability and lowering the inductance. That would solve your problem I have a large swinging xhoke that I will be useing for a powersupply for my transmitter. The only thing you need to do is ensure a minimum current to maintain regulation. Kevin J Pease WB0JZG Mt Juliet, TN. mm1001.theporch.com ------------------------------ Date: Thu, 9 Nov 1995 00:54:00 GMT >From: ralph.hartwell@emachine.com (Ralph Hartwell) To: glowbugs@theporch.com Subject: Re: Looking for a choke... Message-ID: <9511082026273549@emachine.com> GW>>Choke input filters are rarely used in amplifiers for SSB, due to their GW>>tendency to try to maintain current flow at a constant level. With the GW>After doing some reading of the responses here and pondering the meaning of GW>life, I now have second thoughts about the choke input filter approach. In I have built a P/S or two that used a no choke at all but had a BIG filter cap bank and a hefty xfmr so as to keep the caps charged to pretty much the peak xfmr voltage all the time. That eliminates the choke entirely, but does make for some humongous peak current pulses through the rectifiers. The advantage is it's relatively cheap, but beware of the stored charge in the capacitor bank!! GW>input approach. Hmmm... Anyone know of a source for a large variac??? How big do you need and what voltage? Ralph W5JGV --- ~ QMPro 1.53 ~ There are only 3 lawyer jokes...the rest are true stories ------------------------------ Date: Wed, 8 Nov 1995 21:55:48 -1000 >From: Jeffrey Herman To: Boatanchors List , Subject: A Raytheon USSR-made tube? Message-ID: >From dmedley@mail.hvs.comWed Nov 8 08:32:36 1995 Subject: 811A tubes >I have 2 811A tubes looking for a home. One is made in the USSR but has >the Raytheon name the other is US made. Both have good filaments and >that is all I can tell you. I will donate these to someone who has a >real use for them and is willing to take the risk that they are no good. >They look fine. Reply dmedley@indirect.com How is this possible? Did Raytheon contract with the (old) USSR? Would that have been legal? Or did the Soviets "pirate" the Raytheon name? Jeff NH6IL ------------------------------ Date: Thu, 9 Nov 1995 08:29:14 -0500 (EST) >From: Bruce Robertson To: glowbugs@theporch.com Subject: filter caps Message-ID: Looking around our local surplus electonics store yesterday, I found there were no capacitors over 6 microF with voltage ratings of over 450v. Now I have this 400v transformer, see, and a 6L6 that some time soon is going to be forced into service. The store did have 500 microF caps at 250v. Am I right in assuming that one can run these high voltage electrolytics in series and double the voltage carrying (while halving the capacitance)? They also had larger ones with 200v ratings. How close are the tolerances on these ratings? With 400v rectified with a silicon bridge, am I going to get fireworks with 2 200v caps in series? Finally, downstairs in the inductor section there was only one biggish one: a 1.5 H unit. Am I right in thinking that this is just too small to do any good in a cap. input pi filter? 73, VE3UWL Bruce G. Robertson Dept. of Classics, U. of T. ------------------------------ Date: Thu, 9 Nov 1995 09:37:54 -0400 >From: weinfurtner@ouvaxa.cats.ohiou.edu (Greg Weinfurtner) To: glowbugs@theporch.com Subject: Re: filter caps Message-ID: >Looking around our local surplus electonics store yesterday, I found >there were no capacitors over 6 microF with voltage ratings of over 450v. >Now I have this 400v transformer, see, and a 6L6 that some time soon is >going to be forced into service. > >The store did have 500 microF caps at 250v. Am I right in assuming that >one can run these high voltage electrolytics in series and double the >voltage carrying (while halving the capacitance)? > >They also had larger ones with 200v ratings. How close are the tolerances >on these ratings? With 400v rectified with a silicon bridge, am I going >to get fireworks with 2 200v caps in series? > >Finally, downstairs in the inductor section there was only one biggish >one: a 1.5 H unit. Am I right in thinking that this is just too small to >do any good in a cap. input pi filter? > >73, VE3UWL > >Bruce G. Robertson Dept. of Classics, U. of T. > Bruce, Sounds like an ongoing problem... lack of HV electrolytics. Yep yer right, you'll get twice the voltage rating and half the uf if you series two of them. Put a resistor across each of them to keep the voltage equalized (So one of them doesn't get more than half the total voltage)... I forget the formula for exactly the right value...100k seems to ring a bell, but may be someone else can be more exact on this. A rule of thumb for full wave bridges is that you will get roughly 1.4 times the AC voltage that you put into the bridge/capacitor section. In other words: Volts DC= 1.4(ACV). (If your Simpson 260 voltmeter says 12 volts AC going to the bridge, then you will get 16.8vdc on the filter cap.) It will vary with what ever filter type you put after that. Tolerances on the voltage rating actually allow a little more than the labeled rating but I always error on the conservative side! There is nothing quite as startling than an electrolytic exploding! For my DX 60 which uses about 600 vdc, I replaced the failed caps with ones that had 450 wvdc rating. Those two in series give a 900 volt rating. Good news about HV Electrolytics: In computer power supplies these days you'll find they use a switching scheme instead of the conventional ones. There are some great caps to be had here! I am looking at a 200uf 400vdc as I type. And the size is about 1 1/2inch tall and 1 inch diameter! So there may not be such a shortage as we think! 73 de **************************************************************** * NN N SSSSS 888888 OOOOO Greg Weinfurtner AEE BSS * * N N N S 8 8 O O Electronic Design Splst * * N N N SSSSS 888888 O O Ohio University Athens * * N N N S 8 8 O O * * N NN SSSSS 888888 OOOOO * * Canst thou send lightnings * * Amateur Radio NS8O that they may go and say * * unto thee,'Here we are'? * * weinfurtner@ouvaxa.cats.ohiou.edu Job 38:35 * **************************************************************** ------------------------------ Date: Thu, 09 Nov 95 09:38:00 EST >From: "Gable, Edward M" To: glowbugs Subject: RE: filter caps Message-ID: <30A22176@smtpgate.rfc.comm.harris.com> >The store did have 500 microF caps at 250v. Am I right in assuming that >one can run these high voltage electrolytics in series and double the >voltage carrying (while halving the capacitance)? YES, BUT do put equal value resistor across each cap to distribute the voltage evently. I'ts convenient to have your power supply bleeder resistors do this. >They also had larger ones with 200v ratings. How close are the tolerances >on these ratings? With 400v rectified with a silicon bridge, am I going >to get fireworks with 2 200v caps in series? CAPACITOR VOLTAGE ratings are most often working voltage but the rule of thumb is to always go higher. You said "400v rectified" is that 400 VDC after rectification or 400 VAC to be rectified and filtered ? Don't forget the capacitor charges to the peak AC value so it would be 400 VAC x 1.414 (less negligible rectifier drop) = 560 VDC, so you would need three of your 250 volt caps in series with equalizing resistors. Good luck with your project. 73, Ed K2MP @ Rochester emg@rfc.comm.harris.com Finally, downstairs in the inductor section there was only one biggish one: a 1.5 H unit. Am I right in thinking that this is just too small to do any good in a cap. input pi filter? 73, VE3UWL Bruce G. Robertson Dept. of Classics, U. of T. ------------------------------ Date: Thu, 9 Nov 1995 08:06:19 -0700 >From: torell@sicom.com (Kent Torell) To: glowbugs@theporch.com Subject: Re: filter caps Message-ID: Greg Weinfurtner writes: > Good news about HV Electrolytics: In computer power supplies these >days you'll find they use a switching scheme instead of the conventional >ones. There are some great caps to be had here! I am looking at a 200uf >400vdc as I type. And the size is about 1 1/2inch tall and 1 inch >diameter! So there may not be such a shortage as we think! The "universal" ac input section of an ac to dc switching power suppy (at least the ones we use) has to be able to accomodate over 220 vac. Typically, they just go through a rectifier to produce a poorly regulated input (100 to 400 vdc) into the dc to dc converter section. As a result, they need large value, high voltage "hold-up" capacitors. We use hi-rel type switchers from Vicor; they have an Express department that will sell onesy-twosy quantites of their stuff, including hold-up capacitors (with a goodly markup, I suppose). There catalog sez: Part No Description Price 08376 200V, 270 uF $4.50 08377 400V, 270 uF $7.00 08378 450V, 470 uF $12.50 1-800-735-6200 They take credit cards, and surface shipping is free in the U.S. Prices may seem a little high; I haven't checked Newark, ect. Antique Radio Supply had some low value electrolytics I used to repair an old tube radio, but their catalog escapes me at the moment.... Kent Torell KJ7EY Kent Torell torell@sicom.com 602-483-2867 SICOM 7585 E. Redfield, #202 Scottsdale, AZ 85260 ------------------------------ Date: Thu, 09 Nov 1995 11:42:41 -0500 (EST) >From: MODSTEPH@ACS.EKU.EDU To: glowbugs@theporch.com Subject: Re: filter caps Message-ID: <01HXFS2U9HZC000LUZ@ACS.EKU.EDU> Yes - if you put the capacitors in series you get the voltage added and the capacitance halved -- BUT make sure the voltage is divided evenly across the two (or more) by paralleling each individual capacitor with a high ohmage resistor (with appropriate wattage rating) - these act to divide the voltage evenly (same resistance resistors, of course), and double as bleeder resistors. I have done that same thing in a high power amplifier where could not find high enough voltae rated caps to do the job - works fine - and can aalso paralllel another series string for more capacitance, if you have the room. 73, Al N5AIT modsteph@acs.eku.edu ------------------------------ Date: 9 Nov 95 11:26:46 -0600 >From: Paul_Bocci-CPB007@email.mot.com To: glowbugs@theporch.com Subject: RE: filter caps Message-ID: <"Macintosh */PRMD=MOT/ADMD=MOT/C=US/"@MHS> High voltage caps ( up to 400 or 450 Volts) are pretty readily available if you are not particular about the form factor. Digi-Key, amoung others, carries Panasonic parts, both high capacitance values (68 to 560 microfarads at 400 volts) and lower values ( 1 to 33 at 450 volts). I have always been very happy with Digi-Key's service. Their number is 1-800-344-4539. 73 Paul, K9NO CPB007@email.mot.com ------------------------------ Date: Fri, 10 Nov 1995 01:32:39 +0800 (HKT) >From: Wai Kei Leung To: glowbugs@theporch.com Subject: "TWIST LOK" TYPE MULTI-SECTION ELECTROLYTIC CAPCITORS! Message-ID: Dear Sir, I am looking for following US made "TWIST LOK" STYLE multi-section electrolytic capacitors. Please let me know if you have any ready for sale, thanks! 1. 4 sections of 10uF / 450V or 475V or 500V 2. 2 sections of 20uF / 450V or 475V or 500V 3. 3 sections of 20uF / 450V or 475V or 500V 4. 4 sections of 20uF / 450V or 475V or 500V 5. 2 sections of 40uF / 450V or 500V 6. One section of 40uF / 500V and 3 sections of 20uF / 500V 7. One section of 80uF / 450V + one section 50uF /450V + one section of 30uF / 450V 8. One section of 200uF to 200uF / 250V to 300V I also feel interest in other "TWIST LOK" style capacitors. Thanks for your attention! Regards, Wai Kei Leung ------------------------------ Date: Thu, 09 Nov 1995 13:03:24 -0700 >From: Jim Clark To: glowbugs@theporch.com Subject: National NC-140 parts Message-ID: <199511092002.NAA02260@x1.asu.edu> >Date: Thu, 09 Nov 1995 12:56:18 -0700 >To: Boatanchors >From: Jim Clark >Subject: National NC-140 parts > >I'm trying to restore an NC-140, and need to locate someone >who is parting out a junker. I need the Band Spread knob, >which is identical to the Tuning knob. It's 2-1/16" dia, >blue with flutes, no skirt, 1" blue dot in center surrounded >by silver trim ring. I also need the parts that link the >main tuning knob to the tuning cap. This assembly consists >of a large disc that mounts on the tuning cap shaft, and two >pinch-roller discs that mount on the tuning knob shaft. Sure >hope somebody can help me out with this.... >Thanks. > Jim Clark e-mail: jclark@asu.edu ------------------------------ Date: Thu, 9 Nov 1995 13:27:47 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: Auto Radio Tubes FS Message-ID: <199511092027.NAA25538@ns2.indirect.com> Here is a box of tubes which I believe were mostly intended for use in automobile radios before the invention of the transistor. They are unboxed and untested but random samples indicate a very high probality of them being good. 36(2),39(3),39/44(13),44,75(24),77(11),78(28),85(7),89(3) A total of 92 tubes. $0.40 per tube if you take the box. $0.80 per tube in smaller lots. OBO and plus S&H of course. Respond dmedley@theporch.com ------------------------------ End of GLOWBUGS Digest 13 *************************  --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.014" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.014" GLOWBUGS Digest 14 Topics covered in this issue include: 1) Sources for sockets, tools? by mjsilva@ix.netcom.com (michael silva) 2) Choke versus Capacitor Input Filters by "Barry L. Ornitz" 3) Battery Tubes by dmedley@indirect.com (David Medley) 4) Big Boo Boo!!! by dmedley@indirect.com (David Medley) 5) HALLICRAFTERS SX-101A SPEAKER by David Stinson <72227.1640@compuserve.com> ---------------------------------------------------------------------- Date: Thu, 9 Nov 1995 16:16:32 -0800 >From: mjsilva@ix.netcom.com (michael silva) To: glowbugs@theporch.com Subject: Sources for sockets, tools? Message-ID: <199511100016.QAA12429@ix13.ix.netcom.com> Hi, all, It's always the mundane details...for example, does anybody have a source for octal sockets? My local haunts have 7 and 9 pins, but no octals, and I don't want to pay AES' price of almost $3 a pop, so where should I look? Also, where there's a socket there must be a hole (well, usually). I really like the Unibit type of multiple-size bits, and I know some are made to go above 1 inch (octals need 1-1/8 inch, I believe), but I can't find such a large one locally. Any suggestions where to look? I know they're expensive, but they're mighty versatile. Thanks. 73, Mike, KK6GM ------------------------------ Date: Thu, 9 Nov 1995 20:55:44 -0500 (EST) >From: "Barry L. Ornitz" To: Glowbugs Mailing List Subject: Choke versus Capacitor Input Filters Message-ID: I have been waiting to see if anyone else caught this before I replied. Evidently no one did so here goes... Sorry for the length... Greg Wasik, KD1PL, originally asked about a source for a choke for the power supply he was building to go with a 3CX1500A7/8877 amplifier. He had thought about the use of a choke input filter since his available transformer voltage was slightly higher than desired. Bill Turner, W7LZP, replied: A word of caution -- maybe you've already thought about this, but just in case... Choke input filters are rarely used in amplifiers for SSB, due to their tendency to try to maintain current flow at a constant level. With the rapidly varying current drain of an SSB signal, a capacitor-only filter works very well and eliminates the "inductive kick" problem. Two henries is not a lot of inductance, so the problem shouldn't be TOO large, but on the other hand, why have it at all? Personally, I'd go with the variac and the capacitor input. Choke input filters are rarely used in modern amateur radio amplifiers for entirely different reasons. The foremost reason is cost. Chokes are far more expensive than capacitors. The second most important reason is size and weight. With the low duty cycle associated with SSB amplification, modern manufacturers have accepted the poor transformer utilization and poor regulation associated with capacitor-only filters as an acceptable trade-off for keeping the cost down. Of course these commercial amplifiers must be derated for continuous duty operation such as RTTY, FM, and full carrier AM. The modern trend of speech processing, which increases the average power while maintaining the same peak power, also creates problems for these amplifiers. Of course, the distortion associated with speech processing is often so bad that the added distortion from the under-rated linear amplifier is often ignored. Commercial quality amplifiers almost always use choke input filters. Look at the big Collins amplifiers or commercial broadcast stations for example. In fact, for really BIG transmitters, multiphase power is generally used (usually 6 phase) to minimize the filtering requirements. I have no idea what Bill means by the "inductive kick" problem. Properly sized input chokes DO try to maintain their current flow at a constant level, but this is hardly a problem. That is why the choke is there and why properly sized really means "exceeding the critical inductance". Choke input filters give a much better transformer utilization factor exactly for this reason. The demands on the rectifiers are far less severe too. Perhaps a better way to look at this is to look at a capacitor input, or capacitor-only, filter. The classic analysis by Schade [Schade, O. H.: Proceedings I. R. E., 31, 341 (1943)] is probably the best place to start. The basic design curves published by Schade have been reprinted countless times, from texts like Reich and Landee to modern semiconductor design handbooks like those by National Semiconductor and Motorola. They have even appeared in ARRL Handbooks too. Without going into the details (which everyone contemplating homebrew design should do to become familiar with power supply design), it is quite obvious that with capacitor input filters, the rectifier current occurs in short, high-amplitude pulses. With large values of capacitance, needed to get adequate ripple filtering, the peak to average value of the rectifier current can be quite high. This is not generally a big problem with silicon diode rectifiers, but with high vacuum or gas-filled thermionic rectifiers, this problem can be severe. Look in any vacuum tube manual and notice how the ratings for rectifiers are substantially reduced when capacitor input operation is used. Even with silicon diodes, the transformer current waveform can still be a problem. Not only do you have to worry about transformer saturation, you have to worry about noise and voltage spikes sent back into the power line caused by the rapid risetime of these current pulses. With choke input filters, the rectifier and transformer currents occur over larger portions of the AC cycle. The most desired condition is when the inductance is sufficient for the rectifier to pass current through a full cycle of the ripple frequency (120 Hz for full-wave rectified 60 Hz input). A simple analysis can be done to calculate the limiting value of inductance such that the input just falls to zero at the end of the cycle. For a single-phase full-wave rectifier operating at 60 Hz, the inductance works out to be: L = Vout/Iout/1132 = Rload/1132. However, for good regulation the inductance should exceed this value over the whole range of load current. Experimentally Dellenbach and Quinby [Dellenbach, F. S. and R. S. Quinby: QST, Feb. 1932, p. 14 with subsequent discussion in March and April of the same year] determined the value of inductance below which the voltage "soars". This is the relationship usually seen in modern publications: Lcrit = Rload/1000. This also applies to full-wave 60 Hz operation. A good rule of thumb is to provide at least 15% excess inductance over the first equation above. The second equation provides an excess of about 13% and is easy to remember. Considering that the inductance of a choke is a function of the applied current, it is always better to err on the high side. To go back to Greg's original application we can look at Eimac's specifications for the 3CX1500A3/8877. For AB2 SSB operation below 30 MHz, Eimac gives an idle current of 182 mA for a tube voltage of 3500 volts. This means that the needed inductance is greater than approximately 20 Henries. The maximum current (single tone) will be approximately an amp and the amplifier will provide over 2 KW output. This is with a single tube too. The inductance can be decreased at the expense of added current drain on the power transformer. Using a 35Kohm bleeder resistor will add 100 mA to the current draw (and dissipate 350 watts too), but it will decrease the needed inductance to around 12.5 Henries, a much more reasonable value. With an LC filter, it is also possible to use considerably smaller values of capacitance to obtain adequate ripple reduction too. An alternate approach to the use of a big choke is the resonant L-C filtering scheme used by Collins in several of their amplifiers. This approach minimizes the 120 Hz ripple at the expense of higher values of ripple current at higher harmonics. Since these are rarely of much importance with subsequent filtering, this approach can show good benefits. The trade-off is much greater complexity and the need for accurate characterization of the choke's inductance under load. Pappenfus, Bruene & Schoenike discuss this technique in the book on SSB. In conclusion, I hope Greg is able to find a big choke adequate for his application. If he cannot, he should at least go through a Schade analysis for a capacitor input filter and calculate the peak, RMS, and average currents. He may quickly find that vacuum tube rectifiers will be a real problem and that even with silicon diodes, their peak current ratings must be considered too. [A special warning is deserved here. Many so-called 1 KV, 2.5 amp diodes have peak current ratings no higher than 1N4007 1 KV, 1 amp diodes. Paying the extra money for real 3 amp diodes such as the 1N5408 may be worth it.] 73, Barry WA4VZQ ornitz@eastman.com ------------------------------ Date: Fri, 10 Nov 1995 00:18:54 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: Battery Tubes Message-ID: <199511100718.AAA25665@bob.indirect.com> Sometime ago, probably on the BA list, somebody wanted some battery tubes and I have lost track of the message. If you are still out there in cyberspace please contact me dmedley@indirect.com ------------------------------ Date: Fri, 10 Nov 1995 00:29:48 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: Big Boo Boo!!! Message-ID: <199511100729.AAA25691@bob.indirect.com> In my last post re the auto radio tubes I gave some wrong dope re the response address. It should be: dmedley@indirect.com Sorry about that Dave ------------------------------ Date: 10 Nov 95 11:30:40 EST >From: David Stinson <72227.1640@compuserve.com> To: mailing list , Subject: HALLICRAFTERS SX-101A SPEAKER Message-ID: <951110163039_72227.1640_EHM77-2@CompuServe.COM> Well, since I caught the incurable Civilian Rig disease, things have been a little tense around here. My BC-375 won't talk to me. She keeps saying I should go see my "maroon floozie." And my BC-348 says that the SX-101A's case is "probably a bleach-grey." I keep telling them that my military BA's are my first true love, and that this is just a one-time fling. You know how well that went over.... Despite all that, I'm looking for info on the matching speaker for the Hallicrafters SX-101A. What is it and who gots one? After all, if you're going to have a mistress... do it in style. God knows it cost enough... 73 DE Dave Stinson AB5S/7 ------------------------------ End of GLOWBUGS Digest 14 *************************  --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.015" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.015" GLOWBUGS Digest 15 Topics covered in this issue include: 1) OOPS! by David Stinson <72227.1640@compuserve.com> 2) Re: GB- xtal protection / homebrew tubes by Oxyura@aol.com 3) GB: Home-made tubes by Jeffrey Herman 4) PACKRATTING by David Stinson <72227.1640@compuserve.com> 5) Re: OOPS! by af852@rgfn.epcc.Edu (William R Colbert) 6) Re: Sources for sockets, tools? by Bill Turner 7) Re: Choke versus Capacitor Input Filters by Bill Turner 8) Re: Choke versus Capacitor Input Filters by Kevin J Pease 9) FS Battery Tubes by dmedley@indirect.com (David Medley) 10) Re: Choke versus Capacitor Input Filters by mjsilva@ix.netcom.com (michael silva) ---------------------------------------------------------------------- Date: 10 Nov 95 21:30:59 EST >From: David Stinson <72227.1640@compuserve.com> To: mailing list Subject: OOPS! Message-ID: <951111023059_72227.1640_EHM86-1@CompuServe.COM> Sorry about the Halliscrachers post, guys. I forgot this list is homebrew only. Say...does this include questions about home-brew power supplies? I'm thinking of voltage-doubling the filiment winding to get 28VDC out of a Drake AC-4 so I can run a home-brew amp. TNX DE AB5S/7 ------------------------------ Date: Fri, 10 Nov 1995 21:38:28 -0500 >From: Oxyura@aol.com To: glowbugs@theporch.com Subject: Re: GB- xtal protection / homebrew tubes Message-ID: <951110213827_103541274@emout06.mail.aol.com> >The subject of homebrew tubes comes up from time to time. I would like to know if there is any interest or activity in tube manufacture (i.e. homebrew tubes). Thank you. William Lund oxyura@aol.com ------------------------------ Date: Fri, 10 Nov 1995 20:49:59 -1000 >From: Jeffrey Herman To: Glowbugs List Subject: GB: Home-made tubes Message-ID: >From the BA list... Jeff NH6IL --------------------begin forwarded message---------------------- >From: "P.A.Marshall" I was looking at the april '65 QST, on pages 23..25 there is a short bit by a Mr. Sam Diaz Pumara about home built vacuum tubes, it's not a lot but it shows that it can be done. I don't remember this story being mentioned in any of the past past discussions on this subject. Al Marshall "Real Radios Glow in the Dark" almarshall@acm.org >From: Gary Gitzen If anyone is really serious about trying to make their own tubes, I have a sub_micron roughing pump and a diffusion pump I could turn loose. I don't remember the specs on the diffusion pump, but that pair would give a very respectable vacuum. Regards, Gary ------------------------------ Date: 11 Nov 95 09:36:38 EST >From: David Stinson <72227.1640@compuserve.com> To: mailing list , Subject: PACKRATTING Message-ID: <951111143638_72227.1640_EHM74-3@CompuServe.COM> This is an excerpt from a letter to Hank van Cleef. I thought it a good comment, and you do know how I love to preach. Rotten tomatos gracefully received in private email. I'll make spagetti sauce. "....sometimes find these things in the bottom of a junkbox from a hamfest. I paid $10 for this box, pulled-out at least $40 worth of tubes that I use and then handed out the rest. This is the third time I've found an eye tube in a cheap junkbox. I figure it really didn't cost me anything and I don't allow myself to packrat stuff I don't use. I remember too well when, as a kid, I'd see some guy's garage absolutely packed full of BA stuff. No matter how much I might save or find to trade, he wouldn't let any of it go because he was "gonna get around to it some day." Well, someday never came and they buried him and his stuff went to the winds. Lots and lots of BA folks could tell this story. So, I focus on just those radios I care about and everything else goes on the block. Just getting the Johnson was a major diversion from policy for me...." ------------------------------ Date: Sat, 11 Nov 95 08:43:02 MST >From: af852@rgfn.epcc.Edu (William R Colbert) To: glowbugs@theporch.com Subject: Re: OOPS! Message-ID: <9511111543.AA05751@rgfn.epcc.Edu> Dave, I don't remember seeing anything restricting this list to homebrewing only - more to the lowpower end, including the promotion of homebrew. ------------------------------ Date: Sat, 11 Nov 1995 09:07:27 -0800 >From: Bill Turner To: mjsilva@ix.netcom.com, Multiple recipients of list Subject: Re: Sources for sockets, tools? Message-ID: <199511111707.JAA17651@mail.eskimo.com> At 06:18 PM 11/9/95 -0600, michael silva wrote: >Hi, all, > >It's always the mundane details...for example, does anybody have a >source for octal sockets? My local haunts have 7 and 9 pins, but no >octals, and I don't want to pay AES' price of almost $3 a pop, so where >should I look? > >Also, where there's a socket there must be a hole (well, usually). I >really like the Unibit type of multiple-size bits, and I know some are >made to go above 1 inch (octals need 1-1/8 inch, I believe), but I >can't find such a large one locally. Any suggestions where to look? I >know they're expensive, but they're mighty versatile. Thanks. -------------------------------------------------------------------- Here's a thought for mounting octal sockets when you don't want to drill big holes: There are several companies making top-mount octal sockets for plug-in industrial relays. They mount with just a couple of 6-32 screws and work fine with tubes too. They have screw terminals brought out for each pin, so you just connect a wire under the screw and there you are. They're about $4-$5 if bought from the major mail order places, but the surplus houses often have them at a substantial discount. 73, Bill W7LZP wrt@eskimo.com ------------------------------ Date: Sat, 11 Nov 1995 09:07:33 -0800 >From: Bill Turner To: u856010@eastman.com, Multiple recipients of list Subject: Re: Choke versus Capacitor Input Filters Message-ID: <199511111707.JAA17676@mail.eskimo.com> At 07:57 PM 11/9/95 -0600, Barry L. Ornitz wrote: >I have been waiting to see if anyone else caught this before I replied. >Evidently no one did so here goes... Sorry for the length... > >Greg Wasik, KD1PL, originally asked about a source for a choke for the >power supply he was building to go with a 3CX1500A7/8877 amplifier. He >had thought about the use of a choke input filter since his available >transformer voltage was slightly higher than desired. Bill Turner, >W7LZP, replied: > > A word of caution -- maybe you've already thought about this, > but just in case... > > Choke input filters are rarely used in amplifiers for SSB, due > to their tendency to try to maintain current flow at a > constant level. With the rapidly varying current drain of an > SSB signal, a capacitor-only filter works very well and > eliminates the "inductive kick" problem. Two henries is > not a lot of inductance, so the problem shouldn't be TOO > large, but on the other hand, why have it at all? Personally, > I'd go with the variac and the capacitor input. > >Choke input filters are rarely used in modern amateur radio amplifiers >for entirely different reasons. The foremost reason is cost. Chokes >are far more expensive than capacitors. The second most important >reason is size and weight. With the low duty cycle associated with SSB >amplification, modern manufacturers have accepted the poor transformer >utilization and poor regulation associated with capacitor-only filters >as an acceptable trade-off for keeping the cost down. Of course these >commercial amplifiers must be derated for continuous duty operation such >as RTTY, FM, and full carrier AM. The modern trend of speech >processing, which increases the average power while maintaining the same >peak power, also creates problems for these amplifiers. Of course, the >distortion associated with speech processing is often so bad that the >added distortion from the under-rated linear amplifier is often ignored. -snip- ------------------------------------------------------------------ Barry is correct of course about cost, size and weight, but I stand by my original comment about the rapidly varying current draw and the "inductive kick" phenomenon. Inductive kick is familiar to anyone who has powered a relay coil from DC. When the power is removed from the coil, the stored energy in the field attempts to maintain the existing current flow (which it can't) and the result is a sudden voltage spike across the coil. Nearly all designers place a reversed-polarity diode across the coil to absorb the spike. In a power supply, the same effect will happen if a choke is supplying a constant current and the load is suddenly removed (or varied, as with SSB). The difference in a power supply is that the voltage spike is absorbed by the output filter capacitor instead of a diode. My point is that if the capacitor has to be there anyway, why bother with the choke? As an illustration, imagine a power supply with a very large inductance choke and little or no output capacitance. For SSB, it simply wouldn't work. The reverse situation -- big capacitor and little or no choke would work fine. The reason for that is that a power supply for an SSB transmitter should be a constant voltage source, not a constant current source. Barry's other point about the choke smoothing out the load presented to the diodes is also correct and as he points out, is especially important when using tube rectifiers vs solid state diodes. Properly chosen solid state diodes are amazingly resistant to surge currents, and I believe should be used wherever possible, at least at amateur power levels. There is one other consideration when using capacitor-only filtering: The initial current surge on turn-on needs to be taken into account so no components are overstressed. A delay or "step-start" circuit is often used, and in my own station, I have added one to two different commercial amplifiers I have. I chose the component values to allow about three seconds for the capacitors to charge before the full line voltage is applied to the transformer. I've never had a power supply failure with either one, and I credit that partly to the delay circuit. I realize the original poster has gotten some conflicting advice here, but sorting through it should help clarify the issues in his mind, I hope. Electronic design isn't just pure science -- A famous college textbook is entitled "The Art of Electronics" for good reason. 73, Bill W7LZP wrt@eskimo.com ------------------------------ Date: Sat, 11 Nov 1995 13:59:40 -0600 (CST) >From: Kevin J Pease To: glowbugs@theporch.com Subject: Re: Choke versus Capacitor Input Filters Message-ID: We must keep in mind that that inductive kikback is what inductance is all about. The higher the inductance the more the kickback. THe chock stores a magnetic field and that energy is used to fill in the 0 voltage portion of the 120 HZ Pulsating DC. If the chaoc is of the write inductance that Kickbck is desireable and needed. Varrying current requirements don't com into play here. The inductive kickback of the chock is the reason that you don't need large amounts of capacitance in the Choke input filter. The voltage will change with load because of the capacitor charging useing the inductive kickback as a source of energy. A swinging choke will change value to regulate that kickback energy so that at low or high current the voltage is constatnt. The only requirement is a small minimum current that is dependant on the swinging range of the choke. That load is normally provided by the bleader resistors which are needed for safety anyway. I still feel that the choke input circuit is superior to the capacitor input for surge and regulation. Kevin J Pease WB0JZG Mt Juliet, TN. mm1001.theporch.com ------------------------------ Date: Sat, 11 Nov 1995 13:04:38 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: FS Battery Tubes Message-ID: <199511112004.NAA07888@ns1.indirect.com> Here is a box of battery tubes: 1A4(3),1A4P,1A4T(2),1A7GT(5),1A7G(2),1B4(3),1B4T(2),1B5(3),1C6(12),1D5G(2),1 F4,1F5G,1F6G(3),1F6(2),1F7G,1G8G,1H5G(3),1H5GT(2),1H6G(3),1Q5GT,3Q5GT(4) A total of 56 tubes. These are all unboxed and untested. A random test indicates a high probability that most if not all are good. Take the box @$0.50 per tube plus S&H at cost. Reply dmedley@indirect.com ------------------------------ Date: Sat, 11 Nov 1995 13:31:00 -0800 >From: mjsilva@ix.netcom.com (michael silva) To: glowbugs@theporch.com Subject: Re: Choke versus Capacitor Input Filters Message-ID: <199511112131.NAA17760@ix7.ix.netcom.com> I have to admit I never considered "inductive kick" possibility in a filter choke, even though I deal with it all the time in relays, but this must have been dealt with long before SSB. After all, what is CW but full-on/full-off, with a much greater dI/dt than SSB. It sounds like there's more going on in a PS filter than most of us realize. It'd be interesting to scope different points on a filter to see what's happening. 73, Mike, KK6GM ------------------------------ End of GLOWBUGS Digest 15 *************************  --simple boundary--