From lee.stanford@eclipsys.com Tue Apr 22 19:31:34 1997 Received: by csres2.cropsci.ncsu.edu (5.61-AIX-1.2/1.0) from [192.41.32.161] with SMTP id AA117862 (for rdkeys, from lee.stanford@eclipsys.com/lee.stanford@eclipsys.com); Tue, 22 Apr 97 19:31:34 GMT Received: from smtp.eclipsnet.com ([199.250.158.26]) by eclipsys.com (8.8.5) id NAA09267; Tue, 22 Apr 1997 13:30:43 -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 AA861741175; Tue, 22 Apr 97 15:33:32 -0500 Message-Id: <9704228617.AA861741175@smtp.eclipsnet.com> X-Mailer: ccMail Link to SMTP R6.00.01 Date: Tue, 22 Apr 97 12:29:14 -0500 To: Subject: glowbugs digests 21 - 24 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 21 through 24. Sorry, but I do not have number 25. --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.021" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.021" GLOWBUGS Digest 21 Topics covered in this issue include: 1) Re: RF chokes by Steven Wilson 2) GLOWBUGS by BOB.LIESENFELD@hamlink.mn.org (BOB LIESENFELD) 3) Homebrewing tubes by Jeffrey Herman 4) GB:Regen Kit by joe@westonia.com (Joseph Cooper) 5) Heath dipmeter HD-1250 by ralph.hartwell@emachine.com (Ralph Hartwell) 6) QRP List by dmedley@indirect.com (David Medley) 7) water-cooled 6L6s by Duncan Cadd 8) Final word on choke vs capacitor (promise!) by Bill Turner 9) Re: Final word on choke vs capacitor (promise!) by clarke@next3.acme.ist.ucf.edu (Thomas Clarke) 10) Re: Final word on choke vs capacitor (promise!) by Bruce Robertson 11) Re: Back to the future? by "Tony Stalls (K4KYO)" 12) Final word on choke vs capacitor (promise!) by ralph.hartwell@emachine.com (Ralph Hartwell) 13) More unusual tubes by dmedley@indirect.com (David Medley) 14) re: RF chokes by UofSstudent 15) Re: choke vs capacitor/dip by MODSTEPH@ACS.EKU.EDU 16) GLOWBUGS by BOB.LIESENFELD@hamlink.mn.org (BOB LIESENFELD) ---------------------------------------------------------------------- Date: Thu, 16 Nov 1995 16:44:02 -0800 (PST) >From: Steven Wilson To: Steve Byan Cc: Multiple recipients of list Subject: Re: RF chokes Message-ID: Steve you have to watch modern day RF chokes. The ones from yesterday normally had a very low DC resistance. The ones today seem to have a high DC resistance even tho the inductance values are the same. de stan ak0b ------------------------------ Date: Thu, 16 Nov 1995 15:43:19 -0100 >From: BOB.LIESENFELD@hamlink.mn.org (BOB LIESENFELD) To: glowbugs@theporch.com Subject: GLOWBUGS Message-ID: <816549307.AA04264@hamlink.mn.org> Hi gang, Another tale from the "bulb log". 15 some years ago I was "lucky" enough to salvage an old Motorola DC remote, either a T1200 or it's predecessor, from the trash heap of the 2 way shop I was working at. For those of you that aren't familiar with these units they were used to remotely control 2 way radio base stations over phone lines. This thing was full of glowbottles. "What are you going to do with that" was the XYL's comment. Well to be honest I didn't know...But I did know about the *wonderful* audio that sprang forth from this thing.These old remotes really sounded like there was a guy inside...incredible amount of presence. Anyway.. One night I ended up rewiring part of it to operate as a regenerative detector, wound some coils for the 9MHz SW band, and fed the audio to the AF pwr amp bottle. Hooked up my longwire and fired it up.... This was New Years Eve, and the first station I tuned was the old Radio RSA from Johannesburg with a special New Years program. They were taking live phone calls from listeners all over the world. The audio was simply marvelous, until the wind blew, shifting my antenna, and sending my remote/regen over the edge into a screaming howl. This brought inquiries from the XYL as to my sanity. Listened for a while longer and then went up to watch Guy. Don't know whatever happened to the old remote.... Strange how little it took to convert it :-) 72 Bob WB0POQ Technology is OUT of control..... ---NoSnail v1.17 ******************************************************************* HAM>link< RBBS - Serving the Amateur Radio Community Since 1983 - 612/HAM-0000 v.34 Ham Radio Spoken Here!! - 612/HAM-1010 v.32b Reply to sender @ hamlink.mn.org ******************************************************************** ------------------------------ Date: Thu, 16 Nov 1995 16:02:05 -1000 >From: Jeffrey Herman To: Glowbugs List Subject: Homebrewing tubes Message-ID: Here's a mini-thread on building tubes that popped up on Boatanchors. Jeff NH6IL --------------------------------------------------------------------- >From: Larry Keith How about an article on how to make a real tube from old light bulbs? That's the one that I want to read.. 1. Find a 350 watt light bulb. 2. Carefully remove the base. 3. Fabricate grid and plate assembly. 4. Install grid and plate assembly.. 5. Reinstall base into globe. 6. exhaust all that air... etc.. etc... 73, Larry, KQ4BY >From: jmartin@hrlban1.aircrew.asu.edu If only it were that easy. Do you suppose one could make a 'beam power tube' using a headlamp? (OK, stop throwing tomatoes.) Seriously, I still plan to try my hand at making simple tubes in the not-too-distant future. 73, John Martin >From: Bill Sorsby I wonder why the Chinese make such lousy common, non-exotic tubes as the 6V6 and 6146? Could it be that some of the manufacturing processes come close to being an art form? (And one that's largely been lost.) Regards, Bill Sorsby, N5BU >From: "Paul H. Bock" >1. Find a 350 watt light bulb. Or, read the paragraph in "200 Meters and Down" about the young ham of impoverished means who built a complete station by hand, including using discarded bottles from a pharmacy for his tube envelopes. Everything in his station was handcrafted from junk, trash, etc., including winding his own earphones, transformers, etc. The only thing he spent money on was a pair of utility pliers and a second-hand vacuum pump. This was in the late '20s, and according to those who saw his station it was astonishingly well-crafted, efficient and highly functional. Talk about a REAL* homebrewer..... 73, Paul, K4MSG >From: John Shriver Bill Sorsby wrote: I wonder why the Chinese make such lousy common, non-exotic tubes as the 6V6 and 6146? Could it be that some of the manufacturing processes come close to being an art form? (And one that's largely been lost.) Because command economies are one of the sad hoaxes of the 20th Century. (Mostly they are really all kleptocracies anyways.) "Comrade, we met the Five Year Plan and made one million 6146 tubes." "But they don't work worth shit." "That wasn't part of the Five Year Plan. Onward with the Great March Forward!" The tube manufacture processes aren't really an art form. But they are based on continuous process control. The results of extensive testing must continuously be fed back into the manufacturing process. That's something that is really foriegn to a third-world command economy. Certainly not part of the Five Year Plan. Big dams are. Fake farm yield reports are... >From what I hear, there's dirt blowing around on the floor at the Chinese tube factories. Hell, you don't need a clean room, but you do need reasonable cleanliness. The primary process problem the Chinese have is getting the gas out of the tube plates. That's why their power tubes like 6146 and 6550 are losers. They don't heat the plates properly while pumping the vacuum, or the plate metallurgy is crap. When they get up to the graphite anode tubes like the 211 and 845, which are very easy to degas, they apparently make a more acceptable tube! They also make a most respectable 12AX7, but that plate never gets hot in use. Certainly there is no lack of documentation on how to make tubes, there were many journal articles and books on the subject. >From: jmartin@hrlban1.aircrew.asu.edu Bill Sorsby N5BU wrote: I wonder why the Chinese make such lousy common, non-exotic tubes as the 6V6 and 6146? Could it be that some of the manufacturing processes come close to being an art form? (And one that's largely been lost.) ============================================================== Poor quality control of the manufacturing line from accounts I've heard. A retired friend of mine, formerly an engineer with a well-known domestic transmitting tube manufacturer, told me some (sort of) amusing horror stories from when he was a consultant a few years ago and visited a Chinese facility to help them set up a new transmitting tube manufacturing line. Designing and making good tubes consistently on a production basis probably is close to an art form. 73, John Martin jmartin@hrlban1.aircrew.asu.edu ------------------------------ Date: Thu, 16 Nov 95 23:02 EST >From: joe@westonia.com (Joseph Cooper) To: glowbugs@theporch.com Subject: GB:Regen Kit Message-ID: I think I may have found an interesting alternative to the 'Red Hot' Regenerative recv featured in the Sept. issue of CQ magazine. I have just got my 1996 edition of Antique Electronic Supply's Catalog and they are featuring a one tube regenerative recv set based on the 1A5 (or infact a whole group of 1 volt fil tubes). The coil is a spider web design and looks like it could be modified by the looks of it for either 80 or 40. The kit (sold with out the tube) is $21.95 U.S. The tube is about $2.00 and can be bought from the same company (tubes are their mainstay by the way for those who are not familiar with them). The power supply requirments are 1.5 v ('C' Battery) and 45 V (Eveready $12.95 from same company). You can buy a power supply kit from them for $48.50 if needed. The address is 6221 South Maple Av Tempe, Arizona 85283 And their free catalog is just enjoyable to read by itself. I think I will check this out as a 'companion' to that one tube transmitter kit I'm still getting around to building. 73's =================================================================== * 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: Fri, 17 Nov 1995 04:36:00 GMT >From: ralph.hartwell@emachine.com (Ralph Hartwell) To: glowbugs@theporch.com Subject: Heath dipmeter HD-1250 Message-ID: <9511162343004257@emachine.com> T>My grid dipper didn't last forever but almost. T>I have misplaced the manual or lost it. T>Can anyone supply me the two transistor numbers. Sure! Here's the info straight from the Heath manual.. Q # HEATH # TYPE ======================= Q21 - 417-240 - 40637 Q22 - 417-290 - MRF502 Hope this helps! Ralph W5JGV --- ~ QMPro 1.53 ~ The current death rate? One per person, of course. ------------------------------ Date: Fri, 17 Nov 1995 01:46:12 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: QRP List Message-ID: <199511170846.BAA16996@ns2.indirect.com> Can anyone give me the info on the QRP list. I would like to subscribe to it. Dave ------------------------------ Date: Fri, 17 Nov 1995 09:53:16 +0100 (MET) >From: Duncan Cadd To: glowbugs@theporch.com Cc: dcadd@luc.ac.be Subject: water-cooled 6L6s Message-ID: <9511170853.AA22204@alpha.luc.ac.be> Greetings, from a wet and miserable Diepenbeek in N.E. Belgium! Someone posted a note re. water-cooled 6L6s. My Father recalls seeing such a thing, six 6L6s in parallel push-pull, output 420 watts . . . he says the hot water came in handy for the coffee . . . 8-) And I thought getting 50W from a 6L6 was pushing it! Mind you, that was *air*-cooled. We young 'uns don't know the half of it . . . 73, Duncan ON9CHU / G0UTY G-QRP 8117 ------------------------------ Date: Fri, 17 Nov 1995 02:16:51 -0800 >From: Bill Turner To: glowbugs@theporch.com Cc: "Barry L. Ornitz" Subject: Final word on choke vs capacitor (promise!) Message-ID: <199511171017.CAA14243@mail.eskimo.com> Earlier this week Mr. Ornitz and I went back and forth about what the effect of a choke input filter vs a capacitor input filter would be. I don't think either of us convinced the other, so last night I sat down at the 'ol bench and put together a real live power supply to demonstrate the "inductive kick" phenomenon I had referred to. Bear with me a bit, and this should put it to rest. ------------------------------------ Here's a simple experiment you can set up to see the "inductive kick" phenomenon in a real power supply. You don't need to exactly duplicate my setup of course, but here's what I did: I used a transformer with a 28 volt RMS secondary, rated at 1 amp. Anything in this ballpark will do for demonstration purposes. I connected the secondary to a full wave bridge (four 1N4007s) and the output of the bridge through a 5.7 henry choke into a 1 mf capacitor. This basic circuit has been in every handbook since time began and the parts were just ordinary junkbox items, nothing special. With no load at all, the secondary measured 28.8 volts RMS, and the DC output was 39.1. This is just what one would expect -- the secondary RMS voltage times the square root of two, minus two diode drops in the bridge. I then connected a 1500 ohm resistor across the capacitor. This dropped the DC voltage down to 24.1 volts, which means that approximately 16 ma was flowing through the resistor. Now here's the kicker (pun intended): When I disconnected the resistor, the voltage across the capacitor shot up to approximately 54 volts DC and then slowly decayed back to 39.1. This additional voltage is the result of the stored energy in the 5.7 henry choke being suddenly discharged into the 1 mf capacitor -- the "inductive kick" effect. 16 ma isn't much of a load. I now dropped the resistor down to 470 ohms (approximately 48 ma) and when I disconnected the resistor, the DC output shot up to just over 90 volts, and slowly decayed back. Being on a roll, I now dropped the resistor to 150 ohms (about 130 ma) and when I disconnected it, the voltage shot up to an astonishing 138 volts!! This from a "39.1 volt" supply! As a control to the experiment, I removed the choke entirely and repeated the tests. The regulation was poorer, naturally, but the "kick" was entirely gone. In each case, when the load resistor was removed, the DC voltage just quietly returned to 39.1 without a trace of spiking (I watched it on a scope). In a real application, one would make up the lost regulation by increasing the capacitance as necessary. This on-off load is analogous to keying a CW transmitter. If it were SSB, the rate of change would be less and the kick less, but the effect would still be present. Is the picture coming clear? If more proof of the inductive kick effect in a real power supply is needed, I can't imagine what it would be. As I said before, the exact amount of the "kick" will depend on several factors, primarily the inductance of the choke, the capacitance of the capacitor, and the rate of drop of load current. The effect will be greatest with a large choke, small capacitor and extreme drop of load current. What the effect will be in YOUR power supply will no doubt be different from mine, but the effect WILL be there, and should be evaluated before you decide the design is finished. Or better yet, IMHO, skip the choke and go with the capacitor only. Any questions? 73, Bill W7LZP wrt@eskimo.com ------------------------------ Date: Thu, 17 Nov 94 09:55:58 EST >From: clarke@next3.acme.ist.ucf.edu (Thomas Clarke) To: glowbugs@theporch.com Subject: Re: Final word on choke vs capacitor (promise!) Message-ID: <9411171455.AA14776@next3.acme.ist.ucf.edu> Bill W7LZP, peformed some interesting experiments on inductive kick in a choke input filter, using 7.5H and 1 microfarad he obsderved that with a 150 ohm load and 28.8V input to a SS bridge rectifiver: > ... I now dropped the resistor to 150 ohms (about 130 ma) and >when I disconnected it, the voltage shot up to an astonishing 138 volts!! > This from a "39.1 volt" supply! I still wonder if this is realistic simulation of the operation of a real L input filter. First the results are not surprising, the energy in the choke is 1/2(7.5)(.13)^2 ~ .06 joules. The energy in the capacitor after the load is removed is 1/2(.000001)(138)^2 ~ .09 joules. These are equal within experimental error (choke might have been more than 7.5 henries etc). Thus when the the load resistor is removed the stored energy in the coil goes to the capacitor. Second, in a real supply, C would have been larger than 1 microfarad. So that the magnituted or the spike would have been less. Also I think that in the magnitude of the voltage jump would be relatively constant, independent of the supply output voltage, not proportional to it. The energy in the choke depends only on the current through it and the energy in the capacitor depends only on the voltage, so at a given current level the capacitor is kicked up a relatively fixed amount whether the supply is putting out 24 volts or 2400 volts. Third. Even on CW the load does not drop to zero instantaneously. Otherwise you would have the worst key-clicks imaginable. Thus the inductive kick is going to be reducted depending on the keying circuit. Actually, this inductive kick is an interesting pheonomena. It is something I had not thought about in conjuction with a choke input filter. I have learned something from these exchanges. Maybe there's a rule of thumb here somewhere, the energy stored in the choke of a choke input filter should be much less than the energy stored in the output capacitor? Also, the application that started this thread was to get less than 4000 volts from a 4000 volt trasnformer without frying tubes rated at 4000 volts. This is opposed to the traditional reason for a choke input filter - to reduce peak rectifier and transformer currents reducing heating etc. THe presence of the inductive kick shows that the reduced voltage application needs to be careful. The supply may produce 3600 volts under load, but if it kicks above 4000 on transients that would defeat the purpose of the choke. Tom Clarke KE4VFH ------------------------------ Date: Fri, 17 Nov 1995 09:09:11 -0500 (EST) >From: Bruce Robertson To: Bill Turner Subject: Re: Final word on choke vs capacitor (promise!) Message-ID: Bill asked, are there any questions, and I, in the back row, must put up my hand. Everything I've read on choke input filters says that you have to have a bleeder resistor of some value specified by the size of the choke and the voltage output. Hasn't BIll's experiment just proven that and not the deficiencies of a (properly built) choke input? And another question to *really* prove that I don't know what I'm talking about. Why does the plate current *dip* at maximum output? I've done this a million times on my old Heath SB-101, but I can't see the reason. P=E*I, right, so shouldn't maximum current give maximum power? 73, VE3UWL Bruce G. Robertson Dept. of Classics, U. of T. ------------------------------ Date: Fri, 17 Nov 1995 10:08:26 -0500 (EST) >From: "Tony Stalls (K4KYO)" To: michael silva Subject: Re: Back to the future? Message-ID: On Thu, 16 Nov 1995, michael silva wrote: > No, not really, but the new QST does have an unique tidbit. Under the > heading "Who says hams don't build things any more?" they show three > photos of homebrew gear. One is an antique-looking paddle on a wooden > base, another is a very good-looking 1930s-era two-tube receiver, and > the last is a 20 meter tube SSB transceiver, adapted from a 7 MHz > design in "SSB for the Radio Amateur". It was certainly refreshing to see homebrewing featured so prominently, but it should be noted that the latter was accomplished through the blasphemous desecration of a BC-454 command receiver. Let's hope that the builder got it pre-stripped or in otherwise bad shape and didn't destroy a little piece of our history himself. My (probably) overly sensitive griping aside, it did look pretty good though. :-) 73, Tony K4KYO ------------------------------ Date: Fri, 17 Nov 1995 13:56:00 GMT >From: ralph.hartwell@emachine.com (Ralph Hartwell) To: glowbugs@theporch.com Subject: Final word on choke vs capacitor (promise!) Message-ID: <9511170903334300@emachine.com> BT>and put together a real live power supply to demonstrate the "inductive BT>kick" phenomenon I had referred to. Bear with me a bit, and this should put BT>it to rest. Bill, Don't count on it.. good discussions never seem to die. BT>I used a transformer with a 28 volt RMS secondary, rated at 1 amp. Anything BT>in this ballpark will do for demonstration purposes. I connected the BT>With no load at all, the secondary measured 28.8 volts RMS, and the DC BT>output was 39.1. This is just what one would expect -- the secondary RMS BT>voltage times the square root of two, minus two diode drops in the bridge. BT>I then connected a 1500 ohm resistor across BT>the capacitor. This dropped the DC voltage down to 24.1 volts, which means BT>that approximately 16 ma was flowing through the resistor. Now here's the BT>kicker (pun intended): When I disconnected the resistor, the voltage across BT>the capacitor shot up to approximately 54 volts DC and then slowly decayed BT>back to 39.1. BT>This additional voltage is the result of the stored energy in the 5.7 henry BT>choke being suddenly discharged into the 1 mf capacitor -- the "inductive BT>kick" effect. Quite true. This is *exactly* the reason you have to use a minimum load on the supply at all times, commonly called a bleeder resistor. The size is critical. and it *must* be used on *any* choke input power supply for it to regulate properly. BT>As a control to the experiment, I removed the choke entirely and repeated BT>the tests. The regulation was poorer, naturally, but the "kick" was BT>entirely gone. In each case, when the load resistor was removed, the DC BT>voltage just quietly returned to 39.1 without a trace of spiking (I watched Also true. However, cap input supplies will have horrible peak AC line currents and can cause you severe harmonic problems if you have a big enough supply. Everything needs to be bigger - the transformer, (read $$), the power line feed, fuses, caps, rectifiers, etc. Now, in a typical ham supply, this is not a serious consideration, but ask the power companies what happens to the stability of their system when customers place many chokeless power supplies on the AC lines. BT>This on-off load is analogous to keying a CW transmitter. If it were SSB, BT>the rate of change would be less and the kick less, but the effect would BT>still be present. Is the picture coming clear? If you use a bleeder resistor, the DC regulation of a choke input supply is excellent. resistors are generally cheaper than capacitors. BT>If more proof of the inductive kick effect in a real power supply is needed, BT>I can't imagine what it would be. None needed; you have demonstrated it quite effectively. BT>As I said before, the exact amount of the "kick" will depend on several BT>factors, primarily the inductance of the choke, the capacitance of the BT>capacitor, and the rate of drop of load current. The effect will be Again, using a bleeder resistor virtually eliminates this problem, especially if you use a swinging choke. BT>Or better yet, IMHO, skip the choke and go with the capacitor only. Quite acceptable for most ham rigs. I use them here in many of my own gear. Ralph W5JGV --- ~ QMPro 1.53 ~ Genealogies never consider the handsome neighbor ------------------------------ Date: Fri, 17 Nov 1995 11:23:31 -0700 >From: dmedley@indirect.com (David Medley) To: glowbugs@theporch.com Subject: More unusual tubes Message-ID: <199511171823.LAA24284@ns1.indirect.com> I have found another box containing the following: 25 type 6080 1 type 6AS7G 1 type 5931 4 type 6336 I think the 6AS7G is the same as a 6080? These tubes are used extensively in older HP tube type test equipment. AES lists them at $9.00 The 5931 is a ruggedised 5U4 and lists for $19.20 in my AES catalog I have no idea what a 6336 is used for but AES lists them for $49.95 This lot should be useful to someone for $100.00 plus S&H OBO of course. If you would just like some of these tubes let me know and I will break the box up if I don't get an offer for the box lot. 73 de Dave ------------------------------ Date: Fri, 17 Nov 1995 13:15:29 PST >From: UofSstudent To: glowbugs@theporch.com Subject: re: RF chokes Message-ID: On Thu, 16 Nov 1995 11:07:52 -0600 (CST) Steve Byan wrote: > Modern chokes in that inductance range have parallel resonances in the low > megahertz region. For example, the Hammond 2.5 mH choke available from > Antique Electronics Supply has a parallel resonance of 1.3 MHz. The Millen > solenoidal molded RF chokes are worse - the 9250-225 2.2 mH choke has an Fo > of 470 kHz. I think they therefor look pretty capacitive up at 10 or 15 > MHz, and so wouldn't work very well as an RF choke at these higher > frequencies. (BTW, RF chokes seem to me to be part of the real black art of > RF design.) > ... > > If not, what effect does the low impedance through the AF transformer have > on the detector? > > If so, since I can't run down to the radio supply shop and buy a Hammarlund > CH-X choke today, what's a good modern substitute? > > Do I need to buy a coil-winding machine and make my own? What kind of > machine does one need to make pi-wound coils? Yes, Steve, you could be using today's 250 uH chokes. Also , make sure that the choke and associated components don't resonate at the frequencies you wish to receive else you get a dropout ,where the radio doesn't want to regenerate unless you crank up the regen control. This is because you want the rf to feedback to the input, not get wasted in a tank circuit. A non-resonant antenna is a must because the same happens there. You don't want to share the feedback energy with anything except the input coil. That way you could have the feedback loop coupled looser with the input, increasing your Q of the input coil. ie: sharper tuning. In one of the *old books* it mentions how to make a rf choke by winding about 300 scramble-wound turns of #24 wire on a 1/4" wooden dowel. Use a .001uf cap to ground from the cold end of the choke to keep rf out of af transformer. The *effect* of the af transformer's impedance with respect to that of the plate is about the same as that of an audio amplifier using interstage transformers. It sounds OK. For a more compact design and cheaper too, forget the af transformer and use a 10k(experiment here) resistor for plate load, coupled with a .005- .01uf cap. to the grid resistor of the af stage , about 1 meg. Better sound quality. Ideally, a 30H choke should be used instead of plate resistor. Oh well, you can minimize losses but at what co$t? ------------------------------ Date: Fri, 17 Nov 1995 17:18:30 -0500 (EST) >From: MODSTEPH@ACS.EKU.EDU To: glowbugs@theporch.com Subject: Re: choke vs capacitor/dip Message-ID: <01HXRA76YHGY001HUI@ACS.EKU.EDU> The dip in the plate current is not a function of the type of power supply, but a function of tuning a parallel LC circuit to resonance, (the output circuit) which results in its highest impedance. Hence the lowest current. 73, Al N5AIT ------------------------------ Date: Fri, 17 Nov 1995 10:09:00 -0100 >From: BOB.LIESENFELD@hamlink.mn.org (BOB LIESENFELD) To: glowbugs@theporch.com Subject: GLOWBUGS Message-ID: <816620418.AA04275@hamlink.mn.org> Hi gang, Ok, I'm going to reveal a gapping hole in my knowledge about our friend the tube. Remember the old tube type car radios? I also remember hearing about "battery tubes." So, what ran the plates in these tubes? I can't believe that they ran on 12VDC, and can't remember hearing the buzz of a vibrator in the old Fairlane, so what gives? As a novice back in '69, I bought an old Gonset SW converter for a car radio at a hamfest. I asked the guy if he had the power supply for it. He said "there isn't one, it uses battery tubes." It was full of 12AU7s et al........ 72 Bob WB0POQ Technology is OUT of control.... ---NoSnail v1.17 ******************************************************************* HAM>link< RBBS - Serving the Amateur Radio Community Since 1983 - 612/HAM-0000 v.34 Ham Radio Spoken Here!! - 612/HAM-1010 v.32b Reply to sender @ hamlink.mn.org ******************************************************************** ------------------------------ End of GLOWBUGS Digest 21 ************************* --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.022" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.022" GLOWBUGS Digest 22 Topics covered in this issue include: 1) Re: GLOWBUGS by KC5IJD@aol.com 2) GB: Spider Web Coils by joe@westonia.com (Joseph Cooper) 3) Re: GLOWBUGS by Bill Turner 4) Re: GLOWBUGS by af852@rgfn.epcc.Edu (William R Colbert) 5) Re: GLOWBUGS by "Deane D McIntyre" 6) Re: GLOWBUGS by tbowman@leba.net 7) Re: GLOWBUGS by "Tony Stalls (K4KYO)" 8) Re: GLOWBUGS by Bob Roehrig ---------------------------------------------------------------------- Date: Fri, 17 Nov 1995 20:02:25 -0500 >From: KC5IJD@aol.com To: glowbugs@theporch.com Subject: Re: GLOWBUGS Message-ID: <951117200223_25912692@mail04.mail.aol.com> > Remember the old tube type car radios? I also remember hearing about >"battery tubes." So, what ran the plates in these tubes? I can't >believe that they ran on 12VDC, and can't remember hearing the buzz of >a vibrator in the old Fairlane, so what gives? Yes, indeed, there were quite a few tubes manufactured for use with 12 VDC on the plates. I have quite a few of them. As you suspect, these were used in auto radios. There are also one designed for the military which were designed for 26 VDC on plates and filaments (used in the R-392 for instance). Joseph W Pinner Lafayette, LA KC5IJD EMail: kc5ijd@aol.com ------------------------------ Date: Fri, 17 Nov 95 22:10 EST >From: joe@westonia.com (Joseph Cooper) To: glowbugs@theporch.com Subject: GB: Spider Web Coils Message-ID: I sent off an email the other day about the regen kit. One of the features is that it uses the Spider Web style of coil, and they even offer extra coil forms for a couple of bucks so that you can use alternative fequencies (BCB is the default). Im interested in a couple of things regarding these coils. 1) Does anyone know the LC formula for working out L and F for the curcuits using them. The info sure aint in the ARRL Handbook. 2) Why is this design no longer popular. I know that it was a used as a coupling design in some early (1920's) TRF radios and it is still popular with the Xtal Radio crowd. 3) They were used as loop antennas in many cases, but again this design has gone out of favour - any ideas why ? Call me curious. On another note: All this talk about regen radios has brought back memories of the old Alied Radio Span Master kit. I had one that my dad built for me back in 1961, but it got lost over the years. I'm trying to track one down (and I've been in correspondence with some who still have their original sets - won't sell and I don't blame them). If one is available I'd be interested in negotiating for it. 73's =================================================================== * 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: Fri, 17 Nov 1995 19:49:06 -0800 >From: Bill Turner To: BOB.LIESENFELD@hamlink.mn.org, Subject: Re: GLOWBUGS Message-ID: <199511180349.TAA00462@mail.eskimo.com> At 05:47 PM 11/17/95 -0600, BOB LIESENFELD wrote: > Hi gang, > Ok, I'm going to reveal a gapping hole in my knowledge about our >friend the tube. > Remember the old tube type car radios? I also remember hearing about >"battery tubes." So, what ran the plates in these tubes? I can't >believe that they ran on 12VDC, and can't remember hearing the buzz of >a vibrator in the old Fairlane, so what gives? > As a novice back in '69, I bought an old Gonset SW converter for a >car radio at a hamfest. I asked the guy if he had the power supply for >it. He said "there isn't one, it uses battery tubes." It was full of >12AU7s et al........ -------------------------------------------------------------- It's absolutely true. My very first job after graduating high school in 1959 was repairing car radios, and they really did have tubes which had the plate and screen run directly from the 12 volt battery. The design was fairly conventional for the RF amplifier, converter, IF amplifier and first audio, but they chickened out and used a big fat transistor for the audio output. And here's another weird one for the younger generation to ponder.... A few car radio models used a center-tapped voice coil on the speaker and drove it directly with a push-pull transistor amplifier. No transformer, no output coupling capacitor, just a direct connection from the collector of each output transistor to each side of the voice coil. The center of the voice coil went back to the 12 volt supply. I always thought that design was pretty clever, but it only lasted a couple of years and eventually vanished into history. And here's one last thought for you experimental types. The 12-volt tubes mentioned earlier were special types, but they had the same pinout as the common 12AU6, 12BE6, etc, so just on a hunch one day, I substituted the higher-voltage types for the 12-volt ones, and they worked! Not as much gain as a tube designed for 12 volts on the plate, but it was perfectly usable. So how little voltage does a tube need to work? All I know is it's less than 12.... Anyone else have first hand experience with this? 73, Bill W7LZP wrt@eskimo.com ------------------------------ Date: Fri, 17 Nov 95 21:43:41 MST >From: af852@rgfn.epcc.Edu (William R Colbert) To: glowbugs@theporch.com Subject: Re: GLOWBUGS Message-ID: <9511180443.AA01348@rgfn.epcc.Edu> Well, I think the tubes were in the 12AF6 12AD6, etc. Late 50's early 60's which was the vintage of your Gonset Super 12 converter, used those type tubes and 12v was all that was required for the plate. There were several in the magazines of that era and also in the ARRL mobile radio handbook. Sure made it more simple not having to find another box or dynamotor to hook up for B+. 73 Ray, W5XE/V31XE, El Paso, Tx ------------------------------ Date: Fri, 17 Nov 1995 21:59:48 -0700 >From: "Deane D McIntyre" To: glowbugs@theporch.com Subject: Re: GLOWBUGS Message-ID: <9511180459.AA16770@ds1.acs.ucalgary.ca> In message <199511180349.TAA00462@mail.eskimo.com> writes: (Discussion of 12 volt-on-the-plate tubes omited) > And here's one last thought for you experimental types. The 12-volt tubes > mentioned earlier were special types, but they had the same pinout as the > common 12AU6, 12BE6, etc, so just on a hunch one day, I substituted the > higher-voltage types for the 12-volt ones, and they worked! Not as much > gain as a tube designed for 12 volts on the plate, but it was perfectly > usable. So how little voltage does a tube need to work? All I know is it's > less than 12.... Anyone else have first hand experience with this? > No, bit I have first hand with the opposite. Many years ago (about 15) I brought an old Zenith tabletop AM/FM radio for $1 at a garage sale. At that price a couple of tubes were kaput. including the 12BE6 AM converter. I did not have a spare 12BE6, so I stuck in a 12AD6, one of the 12 volt on the plate tubes. Worked fine for many years of service. Recently I dug the radio out. Still worked fine, but I realized my mistake and put in a 12BE6. How the tube survived I wonder...... 73, Deane D McIntyre VE6BPO dmcintyr@acs.ucalgary.ca ------------------------------ Date: Sat, 18 Nov 1995 07:57:15 -0500 (EST) >From: tbowman@leba.net To: af852@rgfn.epcc.Edu, Multiple recipients of list Subject: Re: GLOWBUGS Message-ID: <199511181257.HAA08755@fig.leba.net> About the same time as the Gonset converter, CB Horizons - I'm putting on the flame suit- published a converter for CB/fire frequencies using one tube. I built the 12-volt tube circuit but forget which tube was used. Worked on 33.90 mHz, make that megacycles out of respect, ahead of my car radio as a single tube mixer with an L-C oscilator. So I guess it was a triode-pentode. BTW, I think CB Horizons was a Tom Kneitel product. In a Pop 'Tronics article of the time which I no longer have, there was an article titled "Starved Circuit Amplifier." I'm not sure, but I believe that amplifier was built around a conventional tube with 12 VDC on the plate instead of 250. Gain was pretty hefty. I didn't build that circuit, but I think the point was using conventional tubes at reduced voltages and achieving pretty fair results..73, Tom WA3REY <---- Begin Included Message ----> Well, I think the tubes were in the 12AF6 12AD6, etc. Late 50's early 60's which was the vintage of your Gonset Super 12 converter, used those type tubes and 12v was all that was required for the plate. 73 Ray, W5XE/V31XE, El Paso, Tx ------------------------------ Date: Sat, 18 Nov 1995 08:32:39 -0500 (EST) >From: "Tony Stalls (K4KYO)" To: tbowman@leba.net Subject: Re: GLOWBUGS Message-ID: On Sat, 18 Nov 1995 tbowman@leba.net wrote: > About the same time as the Gonset converter, CB Horizons - I'm putting > on the flame suit- published a converter for CB/fire frequencies using one > tube... OUCH! I nominate you for the bad pun of the day award! :-) 73, Tony K4KYO ------------------------------ Date: Sat, 18 Nov 1995 09:11:19 -0600 (CST) >From: Bob Roehrig To: BOB LIESENFELD Cc: Multiple recipients of list Subject: Re: GLOWBUGS Message-ID: On Fri, 17 Nov 1995, BOB LIESENFELD wrote: > Hi gang, > Ok, I'm going to reveal a gapping hole in my knowledge about our > friend the tube. > Remember the old tube type car radios? I also remember hearing about > "battery tubes." So, what ran the plates in these tubes? I can't > believe that they ran on 12VDC, and can't remember hearing the buzz of > a vibrator in the old Fairlane, so what gives? > As a novice back in '69, I bought an old Gonset SW converter for a > car radio at a hamfest. I asked the guy if he had the power supply for > it. He said "there isn't one, it uses battery tubes." It was full of > 12AU7s et al........ > There were a series of tubes designed especially for use with 12 volt plate supply. This was popular in the early 60's. A lot of the sets were hybrids too. If I remember correctly most, if not all, of these sets were hybrids - that is they used tubes in the RF/IF/DETECTOR stages and the audio was solid state to develop the necessary power. There were circuits using some of the more common tube types also, but most used tubes specially designed for low voltage supply. My 1960 Rambler American had such a radio. 73 de Bob, K9EUI ------------------------------ End of GLOWBUGS Digest 22 *************************  --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.023" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.023" GLOWBUGS Digest 23 Topics covered in this issue include: 1) Spiderweb coils and 12v tubes by kellymed@tmxbris.mhs.oz.au (Murray Kelly) 2) Running low voltage to plate by Jeffrey Herman 3) GB: Points to Ponder by joe@westonia.com (Joseph Cooper) 4) Re: GB: Points to Ponder by HAMRLUND@aol.com 5) Re: GB: Points to Ponder by "Tony Stalls (K4KYO)" 6) IF Transformers by "James P. Rybak" 7) Re: GB: Points to Ponder by Steven Wilson 8) Re: Running low voltage to plate by steve@hi.com (Steve Byan) 9) Re: GB: Points to Ponder by "Tony Stalls (K4KYO)" 10) us and them vs them and us by johnmb@nando.net 11) Re: GB: Points to Ponder by Bob Roehrig ---------------------------------------------------------------------- Date: Sun, 19 Nov 95 13:56:28 AES >From: kellymed@tmxbris.mhs.oz.au (Murray Kelly) To: glowbugs@theporch.com Subject: Spiderweb coils and 12v tubes Message-ID: <635@tmxbris.mhs.oz.au> There was an interesting article in the recent Amateur Radio magazine which is printed by the WIA here. The WIA is very old - founded 1910. Hence the name - Wireless Institute of Australia. I get tired of explaining what wireless is. Anyway, this fellow was using spiderweb coils instead of helical coils and tophats to shorten element lengths on a beam. Claimed it was most successful. My copy is out on loan so I can't quote any numbers (if indeed there were anything other then empirical figures) but if there are, I will send them when it returns. I also have an Audiovox car radio that came in my Alfa Giulia Sprint '64. It is self seeking on BCB and 41m. It is all 12v tubes and two TO3 output transistors. I exchanged it for a transistor receiver after gatting it back from the shop with a flat battery so often. The mechanics would turn it on and forget it. The current drain was much more than they were used to! I too have read that tubes run quite well on 12v even if the specs are for (say) 200v. Amazingly tough. And we push the volts the other way too! Q:. Can anyone explain to me the pros and cons of using a triode power tube 'passive grid'? An old timer told me they used to drive 810 tubes with a grid resistor of 300R from a step up (75:300) transformer. He claimed it didn't need neutralising. I thought this was a little queer and I was sceptical and never followed it up, but it sounds interesting. 'Specially as I have a 10W rig on 20m and a dipole in the attic. SSB, that is, and there are no gentlemen on 20 in that part of the band! Cheers to all. Murray Kelly. vk4aok. ------------------------------ Date: Sat, 18 Nov 1995 20:51:46 -1000 >From: Jeffrey Herman To: Glowbugs List Subject: Running low voltage to plate Message-ID: There is an interesting thread on BA about 12V tubes (in the older broadcast band car radios) and how other tubes that require upwards of 300V can operate at much lower voltages and still provide much gain. I find this truly remarkable. Anyone have any stories on here about running *much* lower than required voltage to the plate of a tube? Jeff NH6IL ------------------------------ Date: Sun, 19 Nov 95 12:19 EST >From: joe@westonia.com (Joseph Cooper) To: glowbugs@theporch.com Subject: GB: Points to Ponder Message-ID: I've got another general question here to ask the group, but before doing so I just wanted to talk about my interest in the group and what I hope to accomplish here. I'm one of the 'young guys' in the group (mid 40's) and came into ham radio during the '70s when tube tech was becoming xmit only. Since then I've learned my solid state theory (even to the point of buying the idea that these little holes are what makes transistors work) and my day job is working with 'leading edge' PC Computers in the support end (hardware and end user technical support). I've come back to tubes and a lot of other 'old technology' because I've come to feel that 'old' does not mean obsolete, and that there are a lot of loose ends that were not tied off, but rather were dropped when 'new' things came into being. Frankly most of the time that things were droped was due to economic reasons (cheaper to make)than any rational reason. Most of the time we have been 'sold' on ideas that the new stuff was better, based on marketing peoples arguments, rather than on real facts. Now I'll be the first to admit that I often get sentimental about the good old days, particularly since they are over and exist only in my imagination. Still and I have found that 'good is good and bad is bad' no matter what time period we are looking at. And there was some really good things being worked on in tube tech that needs to be re-visited and revived if possible. The Audio crowd has been doing this with high end amps and bringing back a full hi-fi sound as a result. Anyway, I will be raising some issue like the spider web coils and other topics that are not directly releated to tubes, but in my mind part of the same issues. So why am I talking about this in this group and not boat anchors ? Well because I feel that the Glowbugs are the experimenters and builders. BA is for the maintenance and restoration of a particular group of manufactured equipment from a particular time period. Nuff said for now. I promise my next post will be on electronics and not philosophy. =================================================================== * 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: Sun, 19 Nov 1995 12:51:49 -0500 >From: HAMRLUND@aol.com To: joe@westonia.com, glowbugs@theporch.com Subject: Re: GB: Points to Ponder Message-ID: <951119125148_86399600@mail04.mail.aol.com> In a message dated 95-11-19 12:26:04 EST, joe@westonia.com (Joseph Cooper) writes: >Steam Railroads see, your not all forgotten. one of my loves also. ************************************************************** CONTACT: Robert Fowle.......Hamrlund@aol.com Ph.517-789-6721............................................... 1215 Winifred....Jackson, Mich. 49202-1946 | | ---|---|---> The HAMMARLUND Historian | | Historical Information -- Manuals -- Technical Material ************************************************************** I'm looking for anything by HAMMARLUND: literature --------> spec sheets, sales flyers, sales catalogs files ----------------> from: factory, service stations, authorized dealers manuals ---------> factory or military accessories ----> speakers, clocks, xtals, xtal boxes, anything face plates------> for sp-200/400/600 series' recievers ------------------------------ Date: Sun, 19 Nov 1995 14:07:55 -0500 (EST) >From: "Tony Stalls (K4KYO)" To: Joseph Cooper Subject: Re: GB: Points to Ponder Message-ID: Hi Joseph, On Sun, 19 Nov 1995, Joseph Cooper wrote: > I've come back to tubes and a lot of other 'old technology' because I've > come to feel that 'old' does not mean obsolete, and that there are a lot > of loose ends that were not tied off, but rather were dropped when 'new' > things came into being. Frankly most of the time that things were droped > was due to economic reasons (cheaper to make)than any rational reason. > Most of the time we have been 'sold' on ideas that the new stuff was > better, based on marketing peoples arguments, rather than on real facts. "Obsolete" is in the eye of the beholder. Although I hesitate to use this example, take the argument that CW should be dropped from amateur radio because its detractors claim it's "obsolete". If it's so out of place, then why, according to an ARRL survey, do 54% of the membership operate CW? Also, try telling Trek, Cannondale, and Schwinn that bicycles are obsolete. That being said, recall the old Univac computers and all their thousands of tubes (12AT7's I think). Perhaps tubes are obsolete in that application. They're probably obsolete in with respect to all the microprocessor based gizmos coming out of Japan these days, that is if somebody really needs all that stuff. None of the receivers from the Land of the Rising Sun perform fundamentally as well as my R-390A. > Now I'll be the first to admit that I often get sentimental about the > good old days, particularly since they are over and exist only in my > imagination. I'll always remember when actor James Mason was being interviewed and made reference to the "good old days". The interviewer asked it the "good old days" were really better and he replied, "Of course they were! I was young then." God rest his soul. :-) > Still and I have found that 'good is good and bad is bad' no matter what > time period we are looking at. And there was some really good things being > worked on in tube tech that needs to be re-visited and revived if possible. > The Audio crowd has been doing this with high end amps and bringing back a > full hi-fi sound as a result. Are the "high-end" audio types really doing that, or are they just elitists? Have you read the high-end newsgroup? I don't think that most have any earthly idea what they're doing, but have literally bought into the philosophy and are paying $100 each for VT-4C's and thousands for tube amplifiers because they're chic. Let's don't get started on this though. > Anyway, I will be raising some issue like the spider web coils and other > topics that are not directly releated to tubes, but in my mind part of the > same issues. Well, I find that interesting and we discussed it at our QCWA chapter meeting yesterday as a direct result of it having been brought up on the Glowbugs. I'll be looking forward to more! > So why am I talking about this in this group and not boat anchors ? Well > because I feel that the Glowbugs are the experimenters and builders. BA is > for the maintenance and restoration of a particular group of manufactured > equipment from a particular time period. Conard has pretty much confirmed that the Glowbugs is for friendly people with the love of traditional tube type gear as the glue that holds us all together. Experimenting, building, fixing, painting, vintage aircraft, recounting personal recollections, and so on appear to all be welcome topics here. I seriously doubt that we'll see the off topic bullying that we've seen in other venues. > Nuff said for now. I promise my next post will be on electronics and not > philosophy. Don't worry about it!! As far as I'm concerned, if you have something to say you feel is of interest to these folks, say it! (Right Conard?) 73, Tony K4KYO ------------------------------ Date: Sun, 19 Nov 1995 12:31:04 -0700 (MST) >From: "James P. Rybak" To: glowbugs@theporch.com Subject: IF Transformers Message-ID: I am looking for some 1600 kc and 460 kc IF transformers and BFO transformers. Please give me a shout if you have any to sell. I'd prefer the larger ones (about 1-1/4" square) but will take the smaller ones (about 3/4" square) if that is all that is available. I am not particular about the brands. I don't think that makes much difference. Jim Rybak W0KSD ------------------------------ Date: Sun, 19 Nov 1995 11:57:19 -0800 (PST) >From: Steven Wilson To: Joseph Cooper Cc: Multiple recipients of list Subject: Re: GB: Points to Ponder Message-ID: Hi Joseph and the group of glowbugs. Like you I make my living from the modern day solid devices. My shack is a mixture of "glowbugs" and solid state devices. Like Tony I find my R390A and Drake 4B to stand up to the present day rice boxes. Not as many "bells and whisles", but technical they can pull a signal out of the mud with the best. They are also very stable for something designed and built over 30 years ago. Size and heat doomed the tubes. Many of the old designs are better than modern day boxes. The packet tnc-2 on rtty can not begin to stand up to the older tube designs. It is often the fault of the designer. I am often called in to fix a design that keeps dieing in the field. It is also apart the fault of the present day - hurry up and ship direction that is given to the newer designers/engineers. Some times the more critical parts of the design are given up to the newest engr in the group. i.e. power supplies. Often the case is designed before the guts then it becomes the problem to fit everything in.. I just revievied a software proposal where it was clear that the firm doing the proposal expected to have to up grade the software which was really firmware.... Also may of today's designs are copycat. i.e. the output capacitor in almost all qrp rigs is a 100 uf or larger. When you see 22 to 47 uf someone took the trouble to actually look at the freq response curve, but not always. hi . So with either tubes or solid state.... The solution is to design for the application... Some of the old tube sets were designed around this fact. Perhaps we can come up with some good glowbug xmitters here on the list that do that, with the result being a combo of tubes and transistors. It is really hard to beat a FET keyer. hi de stan ak0b ------------------------------ Date: Sun, 19 Nov 95 16:56:43 EST >From: steve@hi.com (Steve Byan) To: jherman@hawaii.edu Cc: glowbugs@theporch.com Subject: Re: Running low voltage to plate Message-ID: <9511192156.AA20358@edvac> I have a schematic for a code practice oscillator that uses a type 30 tube with two dry cells for the filament supply *and* for the plate supply. The voltage drop across the heater supplies the plate voltage. Regards, -Steve steve@hi.com ------------------------------ Date: Sun, 19 Nov 1995 16:58:18 -0500 (EST) >From: "Tony Stalls (K4KYO)" To: Steven Wilson Subject: Re: GB: Points to Ponder Message-ID: On Sun, 19 Nov 1995, Steven Wilson wrote: > Size and heat doomed the tubes. Many of the old designs are better than > modern day boxes. Since we're waxing philosophical, what if solid state and LSI chips had been somehow bypassed and all those old designs had been improved upon. I wonder what today's tube designs would have been like. > Also may of today's designs are copycat. i.e. the output capacitor in > almost all qrp rigs is a 100 uf or larger. When you see 22 to 47 uf > someone took the trouble to actually look at the freq response curve, but > not always. hi I don't doubt that. One of my (favorite) arguments alleging that the Japanese manufacturers jave been unfairly competing and conspiring against the (mostly now defunct) US amateur radio industry, who of course were not allowed to collobroate, had to do with the old multi-mode 2 meter rigs, the Kenwood TS-700 and the Yaesu FT-227. (The model numbers are from memory and may not be exactly correct.) I had the Kenwood rig and a friend had the Yaesu, so we did a side-by-side comparison and discovered the circuit diagrams to be almost identical, down to the component values. The other possible explanation, although probably not in the example that you cite, is that the circuit is designed around available components. Folklore tells it that the reason that Wozniak and Jobs selected the radically non-standard disk operating system for their first Apples was because they could get the chips less expensively. Although I'm really a hack-designer (that means I rarely know what I'm doing), I frequently make do with what I have on hand. If it works, I pass what I have along as-is. I'm sure that happens with people who do know what they're doing too. Interesting food for thought! 73, Tony K4KYO ------------------------------ Date: Sun, 19 Nov 95 17:27:10 EST >From: johnmb@nando.net To: glowbugs@theporch.com Subject: us and them vs them and us Message-ID: <9511192227.AA29576@merlin.nando.net> re: "bullying" There are many of us who subscribe to both the BA list and this one. Besides the obvious fact that both lists run on the same machine, and exist because of the benevolence of the same provider, it would be really nice if members who seem to have axes to grind about listowners, politics, or phases of the moon could do so off line, and refrain from raising the blood pressure of others who are not so emotionally involved. I'm only here for the hollow state talk. :-) I know _I'd_ thank you very much.... /john wb5oau/4 ------------------------------ Date: Sun, 19 Nov 1995 18:04:27 -0600 (CST) >From: Bob Roehrig To: "Tony Stalls (K4KYO)" Cc: Multiple recipients of list Subject: Re: GB: Points to Ponder Message-ID: As far as I can tell, back in the "old" days, experimenters were looking for the best coil design, that is, the ideal way to reduce losses. I can't say wether the spider web design was really any "better" than many other designs. I think that using a realatively large wire diameter and reasonable material for the forms should suffice without getting really exotic in the coil design. In some cases it may be ideal to reduce the distributed capacitance, but I would think a decent solenoid type coil would work as well as a spider web or honeycomb design for most applications. If you look back in old QST's, there was a lot of competition in the ads for "low loss coils". The funny thing is that because most of the "tuners" built back then were regenerative, much of the loss would be negated by the inherent high Q derived from the regenerative circuit anyway and probably no matter what coil design was used, the performance of the set was probably always about the same. de Bob, K9EUI ------------------------------ End of GLOWBUGS Digest 23 *************************  --simple boundary Content-Type: text/plain; charset=US-ASCII; name="GLO-POR0.024" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="GLO-POR0.024" GLOWBUGS Digest 24 Topics covered in this issue include: 1) Re: us and them vs them and us by af852@rgfn.epcc.Edu (William R Colbert) 2) One thing leads to another/chicken lips by MIKE SANDERS 3) Re: GB: Points to Ponder by Kevin J Pease 4) Re: Running low voltage to plate by Stan Skelton 5) Re: Running low voltage to plate by Jeffrey Herman 6) Re: Running low voltage to plate by rdkeys@csemail.cropsci.ncsu.edu 7) Re: Running low voltage to plate by mjsilva@ix.netcom.com (michael silva) 8) Re: Running low voltage to plate by rdkeys@csemail.cropsci.ncsu.edu 9) Re: Running low voltage to plate by "Tony Stalls (K4KYO)" 10) Re: Running low voltage to plate by Bill Sorsby 11) Re: Running low voltage to plate by rdkeys@csemail.cropsci.ncsu.edu 12) RF Chokes by "James P. Rybak" 13) Re: RF Chokes by Bob Roehrig 14) RE Tube failure by MODSTEPH@ACS.EKU.EDU ---------------------------------------------------------------------- Date: Sun, 19 Nov 95 18:05:44 MST >From: af852@rgfn.epcc.Edu (William R Colbert) To: glowbugs@theporch.com Subject: Re: us and them vs them and us Message-ID: <9511200105.AA09589@rgfn.epcc.Edu> I guess I missed something - just as well, I do agree in principle John. Now for a related item : I went to the Socorro, NM hamfest yesterday, and not too much in the way of glowing equipment, There was a good collection of keys for sale (NW2F- I think) had lots of Vibroplex and other bugs plus some J-38s and sounders for sale. Nice to see a lot of those set up in one place. There was a beautiful G2DAF receiver on display (marked not for sale) and it was built by AB5J, formerly ZS6KP (I think the calls are correct - didn't take notes at the time). That receiver looked as if it jumped off the pages of the RSGB Handbook of 1968. Another item that may have been for sale (bids were sort of solicited) was a MINT - new out of the box Collins 75A receiver, with speaker and with a little printed history. It was on the same table as the G2DAF receiver and I think my preference was the HB receiver. I left after a couple of hours - so don't know if any other items of interest came in. Oh there was a Tuna Tin QRP xmtr there also. 73, Ray, W5XE, El Paso, Tx ------------------------------ Date: Sun, 19 Nov 1995 22:38:33 -0600 >From: MIKE SANDERS To: glowbugs@theporch.com Cc: Philw7xk@aol.com Subject: One thing leads to another/chicken lips Message-ID: <199511200435.WAA03602@basic.net> Howdy All, A short while ago NH6IL requested info on the lil 6T9 tx. I wrote him as I had built one "by the book" some time back. When I remembered I had given it to a friend I decided to check with him and see if he still had it. He did, it was gathering dust and he would be glad to give it back to me. We met Saturday afternoon and I got the lil tx from him along with a Heath AR-3 rx. The doggone lil rx works and can be cleaned up and tuned up nicely (for what it is and was). The chicken lips as Don Merz puts it, are the missing front panel, knobs and cabinet for the lil rx. I know, I know, fat chance right? Well, I gotta ask anyway. Anyone got any of the afore mentioned laying around? .......I haven't tried out the tx yet, but I have reason to believe it will work fine. The 40 meter coil is in it and I have (somewhere) the 80 meter coil. It should be on the air soon. All 6 or 7 watts of it as I remember. E-mail ks0f@basic.net. 73, Mike ------------------------------ Date: Mon, 20 Nov 1995 08:32:36 -0600 (CST) >From: Kevin J Pease To: Multiple recipients of list Subject: Re: GB: Points to Ponder Message-ID: Kevin J Pease WB0JZG Mt Juliet, TN. mm1001.theporch.com On Sun, 19 Nov 1995, Bob Roehrig wrote: > > If you look back in old QST's, there was a lot of competition in the ads > for "low loss coils". The funny thing is that because most of the "tuners" > built back then were regenerative, much of the loss would be negated by > the inherent high Q derived from the regenerative circuit anyway and > probably no matter what coil design was used, the performance of the set > was probably always about the same. > Well I disagree with the above statment about coil Q not being a large factor in regenerative receiver performance. From experience it is a big factor. The Q-multiplier multiplies the Q useing positive feedback. The Q multiplier amplifies the siganl at resonance but does not atenuate the others. The higher the Q the sharper the peak at resonance and the lower the interfering signals before that peaking. The high Q coils atenuate off frequency signals. This makes the peaked signals even more interference free. Haveing bult manny receivers geting high Q coils has always provided better performance. ------------------------------ Date: Mon, 20 Nov 1995 10:03:57 -0800 (PST) >From: Stan Skelton To: Jeffrey Herman Cc: Multiple recipients of list Subject: Re: Running low voltage to plate Message-ID: I too am interested in hearing from anyone running tube rigs from low voltage sources....waiting with baited breath... 73's Stan...VE7SKT ------------------------------ Date: Mon, 20 Nov 1995 08:29:38 -1000 >From: Jeffrey Herman To: Stan Skelton Subject: Re: Running low voltage to plate Message-ID: On Mon, 20 Nov 1995, Stan Skelton wrote: > I too am interested in hearing from anyone running tube rigs from low > voltage sources....waiting with baited breath... > 73's Stan...VE7SKT This opens up a whole new world of tube QRP possibilities! Imagine not needing the *lethal* HF supply. This might add to tube longevity, too (although as I understand, most tube failure occures from the filament burning up). Jeff NH6IL ------------------------------ Date: Mon, 20 Nov 1995 14:21:26 -0500 (EST) >From: rdkeys@csemail.cropsci.ncsu.edu To: jherman@hawaii.edu Cc: rdkeys@csemail.cropsci.ncsu.edu (), glowbugs@theporch.com Subject: Re: Running low voltage to plate Message-ID: <9511201921.AA120850@csemail.cropsci.ncsu.edu> > > On Mon, 20 Nov 1995, Stan Skelton wrote: > > I too am interested in hearing from anyone running tube rigs from low > > voltage sources....waiting with baited breath... > > 73's Stan...VE7SKT > > This opens up a whole new world of tube QRP possibilities! Imagine > not needing the *lethal* HF supply. This might add to tube longevity, > too (although as I understand, most tube failure occures from the > filament burning up). > > Jeff NH6IL > Look on page 349 of Loomis' ``Radio Theory and Operating'', 1925, and you will find in figure 293 a very nice simple tickler coil transmitter using a UV201A and 22.5 volts of B battery. It is basically a keyed regenerative detector! Back in the WWII days, when my OM was doing radio work at the University of California War Research Lab, Point Loma, they used to use BC-221 freq meters as transceivers around amongst some of the fellers there by keying in the antenna lead. Open and pump for transmitting, close and listen for receiving. That is what I was basically pushing as a minimal rig for the Hartley Rallye, although I opted for a full loose coupled series tuned parallel plate feed Hartley design using a 6/12SN7 or any simple receiving triode like a 6J5 or a 6C4 or even a 955 acorn. Now, to just get the folks to finish whipping one up for the Hartley Rallye.....(:+}}..... 73/ZUT DE NA4G/Bob ------------------------------ Date: Mon, 20 Nov 1995 11:39:03 -0800 >From: mjsilva@ix.netcom.com (michael silva) To: glowbugs@theporch.com Subject: Re: Running low voltage to plate Message-ID: <199511201939.LAA24199@ix7.ix.netcom.com> Jeff wrote: >...This might add to tube longevity, >too (although as I understand, most tube failure occures from the >filament burning up). Hmmm, I've always heard this was mostly just a problem with series-strung heaters, due to the large current surge on power-up. Maybe some of you with more experience can tell us: what are the most common tube failure modes? Low emission? Shorts/leakage? Dropping hot tubes while swapping out? 73, Mike, KK6GM ------------------------------ Date: Mon, 20 Nov 1995 15:15:04 -0500 (EST) >From: rdkeys@csemail.cropsci.ncsu.edu To: jherman@hawaii.edu Cc: rdkeys@csemail.cropsci.ncsu.edu (), glowbugs@theporch.com Subject: Re: Running low voltage to plate Message-ID: <9511202015.AA120968@csemail.cropsci.ncsu.edu> > > On Mon, 20 Nov 1995, Stan Skelton wrote: > > I too am interested in hearing from anyone running tube rigs from low > > voltage sources....waiting with baited breath... > > 73's Stan...VE7SKT > > This opens up a whole new world of tube QRP possibilities! Imagine > not needing the *lethal* HF supply. This might add to tube longevity, > too (although as I understand, most tube failure occures from the > filament burning up). > > Jeff NH6IL > Pass transistor tubes such as the 6AS7G, 6080, 6336, and one more that I can't remember right off have tremendous reserves of emission at low plate voltages. Hence, at 24 volts, they make spunky oscillators, if you can get enough feedback to make them oscillate. The 6AS7G does oscillate easily. The 6080 and 6336 are a bit troublesome. But, if all else fails, then plop a 6SN7 back in the same socket and aways youse goes, even on 12 volts plate. Beware of currents of the 6AS7G, 6080 and 6336 going as high as 350 or 400 ma with both triodes tied together as one, with voltages as low as 48vdc on the plates. 73/ZUT DE NA4G/Bob ..now just start building! ------------------------------ Date: Mon, 20 Nov 1995 16:00:08 -0500 (EST) >From: "Tony Stalls (K4KYO)" To: Stan Skelton Subject: Re: Running low voltage to plate Message-ID: On Mon, 20 Nov 1995, Stan Skelton wrote: > I too am interested in hearing from anyone running tube rigs from low > voltage sources....waiting with baited breath... > 73's Stan...VE7SKT Me too... Power transformers are in such short supply these days, making do with what's available is going to force me into exactly this situation. 73, Tony K4KYO ------------------------------ Date: Mon, 20 Nov 1995 15:20:56 -0600 >From: Bill Sorsby To: glowbugs@theporch.com Subject: Re: Running low voltage to plate Message-ID: <199511202120.PAA13024@dlep1.itg.ti.com> At 03:04 PM 11/20/95 -0600, Tony Stalls wrote: > >On Mon, 20 Nov 1995, Stan Skelton wrote: > >> I too am interested in hearing from anyone running tube rigs from low >> voltage sources....waiting with baited breath... >> 73's Stan...VE7SKT > >Me too... Power transformers are in such short supply these days, making >do with what's available is going to force me into exactly this situation. > >73, >Tony >K4KYO > > For what it's worth, I can offer a point of comparison for doing away with the power transformer. I have both a National NC-57M and an NC-57. They appear to have essentially the same performance, although the NC-57M is an AC-DC radio using about 110 volts for B+, while the NC-57 uses 250 or 300 volts for B+. The tube complement is similar, although not identical. The primary difference in the tubes is that the NC-57M uses some tubes with higher filament voltages, although a number of tubes, including the RF tubes are identical, 6SG7's, 6SN7, 6H6. The voltage regulator tube is 90 volts in the NC-57M and 150 volts in the NC-57. I'm sure the biasing resistors are different between the two, but my recollection is that the circuit diagrams between the two are nearly identical for much of the receiver. Regards, Bill Sorsby, N5BU bill.sorsby@dlep1.itg.ti.com ------------------------------ Date: Mon, 20 Nov 1995 16:53:15 -0500 (EST) >From: rdkeys@csemail.cropsci.ncsu.edu To: j38@clark.net Cc: rdkeys@csemail.cropsci.ncsu.edu (), glowbugs@theporch.com Subject: Re: Running low voltage to plate Message-ID: <9511202153.AA121169@csemail.cropsci.ncsu.edu> > On Mon, 20 Nov 1995, Stan Skelton wrote: > > > I too am interested in hearing from anyone running tube rigs from low > > voltage sources....waiting with baited breath... > > 73's Stan...VE7SKT > > Me too... Power transformers are in such short supply these days, making > do with what's available is going to force me into exactly this situation. > > 73, > Tony > K4KYO FEOI (new acronym For EveryOne's Information)...... My experiences over the past 20 years with Glowbugs (mostly hartleys and regenerators) has made me a firm believer in the utility of small sealed lead acid batteries for globugging use. I find the 7 and 10 ah sized 6/12 volt ``gel cells'' (band nomenclature because they are really just plain sealed lead acid batteries from Yuasa, Panasonic, etc., if one reads the manuals on them), when placed in sets of batteries to give 24 or 48 volts in small wooden trays (cut from what sorts of scrap wood I can muster up) works most magnificently for all filament and B+ uses. Hook up several trays as required. Using low plate voltages on oscillators require that careful attention to grid biasing be used (like play with the grid tap on the oscillator coils etc.). Using low plate voltages on detectors and audio tubes usually requires that good throttle control of regeneration be had AND some means of adjusting the feedback ticklering turns is usually advantageous. I get mine for a dollar a battery from the local junque recycling emporium in scrap, and if the batteries are relatively fresh, they work fine at low currents in receiver or transmitter use. They will usually last for several years on the bench. They are expendable at that price. Other than that, GO FOR IT...... news at 11, Hartleys running on the Globugging QRG of 1805khz on 200 meters and down, at 10 EST....etc., etc. 73/ZUT DE NA4G/Bob ------------------------------ Date: Mon, 20 Nov 1995 14:33:05 -0700 (MST) >From: "James P. Rybak" To: Glowbugs Subject: RF Chokes Message-ID: Should the self-resonant frequency of an RFC be above or below the frequency of operation? By how much? Thanks Jim Rybak ------------------------------ Date: Mon, 20 Nov 1995 16:06:26 -0600 (CST) >From: Bob Roehrig To: "James P. Rybak" Cc: Multiple recipients of list Subject: Re: RF Chokes Message-ID: On Mon, 20 Nov 1995, James P. Rybak wrote: > Should the self-resonant frequency of an RFC be above or below the > frequency of operation? By how much? I always try and have it below the lowest frequency of operation. By the way, according to the books, it is the SERIES RESONANT point that should be avoided. That is where the impedance is minimum and the choke looks like a short. The series resonant frequency can be determined by shorting the ends of the choke together and measuring resonance with a grid dip meter. I distinctly remember having problems with a couple of National RF chokes. One was in the plate of a pair of 4-125's I had on 80 meters. The choke was resonant there and would "blow" out the winding at the top of the form. Another choke was resonant in the 15 meter band. So I always check the self resonance of chokes - especially if they are to be used in transmitters. I also learned the hard way not to wind transmitting chokes on PVC. They can get hot enough to melt the form! 73 de Bob, K9EUI ------------------------------ Date: Mon, 20 Nov 1995 17:15:21 -0500 (EST) >From: MODSTEPH@ACS.EKU.EDU To: glowbugs@theporch.com Subject: RE Tube failure Message-ID: <01HXVGZOQVVO002HPU@ACS.EKU.EDU> For me the most common failure is low emission, followed by internal shorts (in the tube, dummy - keep my shorts out of this!). Filament failure is rare by comparison to these other two. 73, Al N5AIT modsteph@acs.eku.edu ------------------------------ End of GLOWBUGS Digest 24 *************************  --simple boundary--