20091015.ba v04_n292.bam.20091015 >From ???@??? Thu Oct 15 23:18:45 2009 -0600 Date: Thu, 15 Oct 2009 22:17:44 CST From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4292 Message-Id: <20091016041746.564E8D58BB@srvr1.theporch.com> BOATANCHORS Digest 4292 Topics covered in this issue include: 1) RE: ARRL Antenna Handbook data -- data received! by John Sehring 2) Re: ARRL Antenna Handbook data by "Brian Clarke" 3) Re: ARRL Antenna Handbook data by Rhett George 4) Willing to proof read? by John Sehring 5) TMC-GPR90 by "Guido" 6) Re: TMC-GPR90 by Heinz Breuer 7) Re: TMC-GPR90 by wb3fau@att.net 8) Re: TMC-GPR90 by "P.J. Rovero" 9) Re: TMC-GPR90 by WA5CAB@cs.com 10) "Geezers" by "KEN" 11) Re: TMC-GPR90 by "Guido" 12) RE: TMC-GPR90 by "Singley, Rodger" 13) Re: TMC-GPR90 by John Poulton 14) Re: TMC-GPR90 by wb3fau@att.net 15) Thank You, Mr. R-390 THIEF by "David Stinson" 16) BC-186 by Al Klase 17) R-388 Meter Problem by "Michael Hardie" 18) Re: R-388 Meter Problem by Al Klase 19) LOOKING FOR NC-100A by "WA3GIN" 20) R-388 Meter Problem 2 by "Michael Hardie" 21) Re: R-388 Meter Problem 2 by spr@earthlink.net 22) Re: R-388 Meter Problem 2 by Al Klase 23) Re: R-388 Meter Problem 2 by mac ---------------------------------------------------------------------- Message-ID: <214689.78081.qm@web45610.mail.sp1.yahoo.com> Date: Mon, 12 Oct 2009 16:31:50 -0700 (PDT) From: John Sehring Subject: RE: ARRL Antenna Handbook data -- data received! To: Old Tube Radios MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Thanks to Richard, who emailed me a .jpg of just what I needed! What a great group! My year 2000 ARRL Ant. Hdbk has been wrapped in plastic since I bought in 2001! I just opened it up. So, it's "new" to me, but I will eventually buy the latest one. BTW, have spent a large amount of time modeling the 3 and 4 element 10m Yagi's using EZNEC. They look excellent on the computer & will probably be excellent on the air. It appears to me that they've been thoroughly optimized. I've been doing this sort of thing since 1987 so I hope I've learned how to do a decent job of antenna modeling! 73 from John WB0EQ/VE6 ------------------------------ Message-ID: From: "Brian Clarke" To: Old Tube Radios Subject: Re: ARRL Antenna Handbook data Date: Tue, 13 Oct 2009 17:44:20 +1100 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit You could say the same about the gun - and be just as wrong. It is the human intention and usage, not the machine that makes the criminal act. 73 de Brian, VK2GCE. ----- Original Message ----- From: "mac" To: "Old Tube Radios" Sent: Tuesday, October 13, 2009 8:40 AM Subject: Re: ARRL Antenna Handbook data > Alas, the Zerox machine and it's spawn have made criminals of us > all........... > > Dennis D. W7QHO > Glendale, CA > > > > On Oct 12, 2009, at 2:21 PM, Brian Clarke wrote: > >> I believe that this book is still within its copyright period. Please >> have a careful look at copyright law before you copy any material - >> whether you sell that copy or not. I think you may find that both the >> copier and the person who receives the copy may be indictable. Be >> careful. >> 73 de Brian, VK2GCE. >> >> ----- Original Message ----- From: "John Sehring" >> To: "Old Tube Radios" >> Sent: Tuesday, October 13, 2009 5:26 AM >> Subject: ARRL Antenna Handbook data >> >> >>> Favor please? >>> >>> My ARRL Antenna Handbook is from 2000. It doesn't contain the latest >>> data on Yagi antennas that the newest or newer versions have. >>> Specifically, in Chapter 11, there're 10m Yagi designs for 2 elements >>> and up. >>> >>> In my older Handbook, the 2-element 10m version is missing. Could >>> someone scan or transcribe the data for it & send it to me? >>> >>> Please reply off list. Thanks & happy Thanksgiving! >>> >>> --John WB0EQ >>> >>> >>> >>> >> > > ------------------------------ Date: Tue, 13 Oct 2009 12:12:43 -0400 From: Rhett George To: Old Tube Radios Subject: Re: ARRL Antenna Handbook data Message-ID: <20091013161243.GC6098@ee.duke.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Oct 13, 2009 at 05:44:20PM +1100, Brian Clarke wrote: > You could say the same about the gun - and be just as wrong. It is the > human intention and usage, not the machine that makes the criminal act. > 73 de Brian, VK2GCE. > > - Greetings - This brings to mind that scourge of the Alamo, particularly his last clause. "Manifesto by General Antonio Lopez de Santa Anna, ca 1837 "How could I divert the sword of justice from their heads without making it fall upon my own? Let it be said, if you want, I confess that it is not my opinion that the law was unjust, but can there be no greater blindness than to impute the crime to the dagger and not to the hand that wields it?" 73 Rhett KE4HIH ------------------------------ Message-ID: <617785.91964.qm@web45613.mail.sp1.yahoo.com> Date: Tue, 13 Oct 2009 14:21:47 -0700 (PDT) From: John Sehring Subject: Willing to proof read? To: Old Tube Radios MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Hello All, I'm working on an article for QST/QEX. It involves a bit of ntenna theory, Yagi antenna designs, and the use of EZNEC for antenna modeling. I'd welcome those interested to review this article for me. There's a LOT of accumulated wisdom here & I'd appreciate the opportunity to include that! Pse email me off list if interested. Thanks so much. --John WB0EQ/VE6 ------------------------------ Message-ID: <001401ca4c61$7bdcd850$4400000a@CPQ10443900021> From: "Guido" To: Old Tube Radios Subject: TMC-GPR90 Date: Tue, 13 Oct 2009 20:01:29 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit A stroke of luck allowed a GPR 90 to follow me home today. I never thought that I would see one in this island but your never know. It is complete with cabinet and only one cabinet foot is missing. Now, it is not beautiful and needs a lot of TLC so any recommendations on this one will be welcome. I am just cleaning it right now. I could not let it go for 40 green ones at a used things store. Best 73s Guido Santacana KP4FAR ------------------------------ Message-ID: <4AD517FF.7070407@debitel.net> Date: Wed, 14 Oct 2009 02:14:55 +0200 From: Heinz Breuer MIME-Version: 1.0 To: Old Tube Radios CC: Old Tube Radios Subject: Re: TMC-GPR90 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit A great find . You should go out again and buy a lottery ticket today. 73 de Heinz DH2FA, KM5VT Guido schrieb: > A stroke of luck allowed a GPR 90 to follow me home today. I never > thought that I would see one in this island but your never know. It is > complete with cabinet and only one cabinet foot is missing. Now, it is > not beautiful and needs a lot of TLC so any recommendations on this one > will be welcome. I am just cleaning it right now. I could not let it go > for 40 green ones at a used things store. > > Best 73s > Guido Santacana KP4FAR > > ------------------------------ From: wb3fau@att.net To: Old Tube Radios Cc: "Guido" Subject: Re: TMC-GPR90 Date: Wed, 14 Oct 2009 00:28:01 +0000 Message-Id: <101420090028.25917.4AD51B11000761CD0000653D22230703729B0A02D29B9B0EBF9A0E00CC0D99@att.net> for $40? Geez Guido, what a find! very nice general coverage receiver a true boat-anchor. Now, you need to find the the companion transmitter- GPT-750! Russ. ------------------------------ MIME-Version: 1.0 Message-ID: <61930.1255482618@ct.metrocast.net> To: Old Tube Radios Content-Type: text/plain; charset="utf-8" Date: Tue, 13 Oct 2009 21:10:18 -0400 Subject: Re: TMC-GPR90 From: "P.J. Rovero" Content-Transfer-Encoding: quoted-printable Guido, A decent manual for it will probably cost more than the radio! Congratulations.... P.J. "Josh" Rovero Ham Radio: KK1D ABC: 9277 1985 BMW R80RT Web: http://www.roveroresearch.org On Tue 10/13/09 20:01 , "Guido" laffitte@prtc.net sent: > A stroke of luck allowed a GPR 90 to follow me home today.=20 ------------------------------ From: WA5CAB@cs.com Message-ID: Date: Tue, 13 Oct 2009 22:48:10 EDT Subject: Re: TMC-GPR90 To: Old Tube Radios MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_bbb.5b106d6f.380695ea_boundary" --part1_bbb.5b106d6f.380695ea_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Actually, not quite. :-) $18.00 plus shipping for reprint of the basic plain vanilla GPR-90 manual. If I understood correctly that you got the radio for $40, that was a find. In a message dated 10/13/2009 8:11:04 PM Central Daylight Time, provero@ct.metrocast.net writes: > Guido, > > A decent manual for it will probably cost more than the radio! > > Congratulations.... > > P.J. "Josh" Rovero Ham Radio: KK1D > ABC: 9277 1985 BMW R80RT > Web: http://www.roveroresearch.org > > On Tue 10/13/09 20:01 , "Guido" laffitte@prtc.net sent: > >A stroke of luck allowed a GPR 90 to follow me home today. Robert & Susan Downs - Houston wa5cab dot com (Web Store) MVPA 9480 --part1_bbb.5b106d6f.380695ea_boundary Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * --part1_bbb.5b106d6f.380695ea_boundary-- ------------------------------ Message-ID: <000601ca4cbf$f5e572c0$020fa8c0@yourb27fb1c401> From: "KEN" To: Old Tube Radios Subject: "Geezers" Date: Wed, 14 Oct 2009 06:17:47 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0003_01CA4C96.0C938400" This is a multi-part message in MIME format. ------=_NextPart_000_0003_01CA4C96.0C938400 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Folks, Someone sent a good "funny" story about "Geezers"! I have lost it. Will that person please repeat it for me? Take care, Ken N5CM ------=_NextPart_000_0003_01CA4C96.0C938400 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_0003_01CA4C96.0C938400-- ------------------------------ Message-ID: <003e01ca4cd8$159a96a0$4400000a@CPQ10443900021> From: "Guido" To: Old Tube Radios Subject: Re: TMC-GPR90 Date: Wed, 14 Oct 2009 10:10:27 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="utf-8"; reply-type=original Content-Transfer-Encoding: 7bit Thanks all for the nice comments. I cleaned the GPR yesterday and found a major problem. The power transformer primary is shorted. The transformer was tested with tubes out and a variac to bring it up carefully. Even at less than 90AC it started to blow out the 2 amp fuse. This transformer is a 275-0275 at 100ma, 5V at 3amps and 6V at 5.65A. Anyone got something similar before I plunge into a new one? And it was such a nice find! Best 73s Guido KP4FAR ------------------------------ Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Subject: RE: TMC-GPR90 Date: Wed, 14 Oct 2009 09:28:00 -0500 Message-ID: From: "Singley, Rodger" To: Old Tube Radios R3VpZG8sDQoNClRoZXJlIGFyZSBhIG51bWJlciBvZiBieXBhc3MgY2FwcyBvbiB0aGUgZmlsYW1l bnQgbGluZSB0byBncm91bmQ7IG1ha2Ugc3VyZSB5b3UgZG9uJ3QgaGF2ZSBhIHNob3J0IGhlcmUg YmVmb3JlIHlvdSBjb25kZW1uIHRoZSBwb3dlciB0cmFuc2Zvcm1lci4gIEFsdGhvdWdoIHVubGlr ZWx5LCBhbHNvIGNoZWNrIGZvciBjYXJib24gdHJhY2tpbmcgb3IgYSBzaG9ydCBiZXR3ZWVuIHRo ZSBodiBzZWNvbmRhcnkgbGVhZHMgYXQgdGhlIHJlY3RpZmllciBzb2NrZXQuDQoNCkkgaW1hZ2lu ZSBhIEhhbW1vbmQgMjcwSFggd291bGQgZmlsbCB0aGUgYmlsbCBpZiB5b3UgaGF2ZSB0byBidXkg YSBuZXcgb25lLiAgT2YgY291cnNlIGlmIHlvdSBhcmUgd2lsbGluZyB0byBzd2l0Y2ggdG8gYSBz b2xpZCBzdGF0ZSByZWN0aWZpZXIgc2V0dXAgdGhlbiB5b3UgaGF2ZSBhIGxvdCBvZiBwb3dlciB0 cmFuc2Zvcm1lciBvcHRpb25zIHNpbmNlIHlvdSB3b24ndCBuZWVkIHRoZSA1IHZvbHQgd2luZGlu ZyBhbmQgeW91IGNvdWxkIGFsc28gdXNlIGEgZnVsbCB3YXZlIGJyaWRnZSBzZXR1cCB0aHVzIGF2 b2lkaW5nIHRoZSBuZWVkIGZvciBhIGNlbnRlciB0YXBwZWQgc2Vjb25kYXJ5Lg0KDQpSb2RnZXIg V1E5RQ0KDQo+IC0tLS0tT3JpZ2luYWwgTWVzc2FnZS0tLS0tDQo+IEZyb206IG93bmVyLWJvYXRh bmNob3JzQHRoZXBvcmNoLmNvbSBbbWFpbHRvOm93bmVyLQ0KPiBib2F0YW5jaG9yc0B0aGVwb3Jj aC5jb21dIE9uIEJlaGFsZiBPZiBHdWlkbw0KPiBTZW50OiBXZWRuZXNkYXksIE9jdG9iZXIgMTQs IDIwMDkgOToxMCBBTQ0KPiBUbzogT2xkIFR1YmUgUmFkaW9zDQo+IFN1YmplY3Q6IFJlOiBUTUMt R1BSOTANCj4gDQo+IFRoYW5rcyBhbGwgZm9yIHRoZSBuaWNlIGNvbW1lbnRzLiBJIGNsZWFuZWQg dGhlIEdQUiB5ZXN0ZXJkYXkgYW5kIGZvdW5kDQo+IGENCj4gbWFqb3IgcHJvYmxlbS4gVGhlIHBv d2VyIHRyYW5zZm9ybWVyIHByaW1hcnkgaXMgc2hvcnRlZC4gVGhlDQo+IHRyYW5zZm9ybWVyIHdh cw0KPiB0ZXN0ZWQgd2l0aCB0dWJlcyBvdXQgYW5kIGEgdmFyaWFjIHRvIGJyaW5nIGl0IHVwIGNh cmVmdWxseS4gRXZlbiBhdA0KPiBsZXNzDQo+IHRoYW4gOTBBQyBpdCBzdGFydGVkIHRvIGJsb3cg b3V0IHRoZSAyIGFtcCBmdXNlLiBUaGlzIHRyYW5zZm9ybWVyIGlzIGENCj4gMjc1LTAyNzUgYXQg MTAwbWEsIDVWIGF0IDNhbXBzIGFuZCA2ViBhdCA1LjY1QS4gQW55b25lIGdvdCBzb21ldGhpbmcN Cj4gc2ltaWxhcg0KPiBiZWZvcmUgSSBwbHVuZ2UgaW50byBhIG5ldyBvbmU/DQo+IEFuZCBpdCB3 YXMgc3VjaCBhIG5pY2UgZmluZCENCj4gQmVzdCA3M3MNCj4gR3VpZG8gS1A0RkFSDQoNCg== ------------------------------ Date: Wed, 14 Oct 2009 11:20:25 -0400 (EDT) From: John Poulton To: Old Tube Radios cc: Old Tube Radios Subject: Re: TMC-GPR90 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Guido, and the group, This is an extremely common problem in GPR-90's. I've "gone through" about a dozen of these receivers, and well over half of them had blown power transformers. I've had good success using Transformer Rewinding Service in Orono, ME. Gary does a *great* job and knows these particular transformers all too well, having rebuilt about a half-dozen of them for me. Be sure to ask him to wind the primary for 125V (instead of the original 115V). The other components in the radio will thank you :) So, send Gary your transformer, wait a few weeks, and you're back in business. At $150 or less (you'll have to ask Gary for latest prices), you're STILL way ahead of the curve for this particular receiver. Another fairly common problem that you may encounter: dead crystal at the 2nd mixer. If so, please ask, and I'll send you the specs for this item. It operates in a series- resonant mode. I have the "fixture capacitance" somewhere in my notes. Getting TO the xtal is another story.. it's an 'interesting' problem, but one that's fairly easy to solve :) And, of course, you can download a free manual from: http://jptronics.org/radios/TMC/manuals/ 73, John K4OZY On Wed, 14 Oct 2009, Guido wrote: > Thanks all for the nice comments. I cleaned the GPR yesterday and found a > major problem. The power transformer primary is shorted. The transformer was > tested with tubes out and a variac to bring it up carefully. Even at less > than 90AC it started to blow out the 2 amp fuse. This transformer is a > 275-0275 at 100ma, 5V at 3amps and 6V at 5.65A. Anyone got something similar > before I plunge into a new one? > And it was such a nice find! > Best 73s > Guido KP4FAR > > -- ------------------------------ From: wb3fau@att.net To: Old Tube Radios Cc: "Guido" Subject: Re: TMC-GPR90 Date: Wed, 14 Oct 2009 23:38:23 +0000 Message-Id: <101420092338.686.4AD660EF00097F9F000002AE22243323629B0A02D29B9B0EBF9A0E00CC0D99@att.net> You might try Fair Radio Sales, a tranny from a SP-600 might be a good sub? Russ. ------------------------------ Message-ID: <6724E8AFF35F42E5A931D2DD7F3F703F@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: Thank You, Mr. R-390 THIEF Date: Wed, 14 Oct 2009 21:53:12 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit I had two nice, 6-foot Navy gray R-390 mounting racks in my yard in Nevada, Texas. The heavy steel 4-square ones with the solid bottoms. One even still had its nomenclature plate. I made the mistake of saying I was going to work out a trade on one of the local Dallas repeaters (stupid me) :-\. Well, they walked away one dark night. Lots of other things a common thief would want were untouched; he took only the racks. So.... if you see an R-390 person bragging about his two new racks, please tell him that, when he gets through pimping his mother to Mexican sailors for ten pesos each, he might drop me an email and let me know how he likes his racks. He'll be back.... thieves always over-reach... This is Texas.... my 12-gauge will be waiting..... ------------------------------ Message-ID: <4AD77903.5030008@ar88.net> Date: Thu, 15 Oct 2009 15:33:23 -0400 From: Al Klase MIME-Version: 1.0 To: Old Tube Radios Subject: BC-186 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Gang, A recent rearrangement of the radio collection has me considering waking up my BC-186. This is the TRF-autodyne receiver that is part of the SCR-178 mule-pack station. My set was partially modified, and has octal sockets where the 30's are supposed to go. I have replacement sockets, but there are some other problems lurking here. RF transformer, T-2, Type C-134, has an open winding and is resisting coming out of its can. Does anyone have a spare? For that matter, are there other coils for this receiver beyond the 2400-3700 KC range? I'm also in the market for the 5-pin power connector. Nice pix on NS1W's page if you're curious: http://people.csail.mit.edu/sw/html/NS1W/scr-178.html Thanks, Al -- Al Klase - N3FRQ Jersey City, NJ http://www.skywaves.ar88.net/ ------------------------------ Message-ID: From: "Michael Hardie" To: Old Tube Radios Subject: R-388 Meter Problem Date: Thu, 15 Oct 2009 16:33:11 -0700 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit The meter on my R-388 does not respond to any strength signal. The meter works normally with the meter switch in the output position. With the meter switch in the input position the meter deflection is zero with RF gain wide open, and as the RF gain is decreased to zero the meter deflection goes proportionally to 100, position of the AVC switch has no effect. Resistance and voltage measurements around V110 and V111 are normal, the tubes have been checked OK. The alignment is dead on so far as I can tell, same indications on all bands, reception of stations is fine, except the meter stays at zero. Any help on where to go from here will be appreciated. The bench has the usual test gear. Mike VE7MMH ------------------------------ Message-ID: <4AD7B767.5070206@ar88.net> Date: Thu, 15 Oct 2009 19:59:35 -0400 From: Al Klase MIME-Version: 1.0 To: Old Tube Radios CC: Old Tube Radios Subject: Re: R-388 Meter Problem Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit And, the receiver works normally, i.e. has normal AVC action with the AVC switch in the "ON" position with RF GAIN wide open? I doubt it. The fact that the meter responds to the RF GAIN controls says to me that the meter circuit is functioning properly, Do you see AVC voltage on the V111 side of the switch? Bad switch? Al Michael Hardie wrote: > The meter on my R-388 does not respond to any strength signal. The > meter works normally with the meter switch in the output position. > With the meter switch in the input position the meter deflection is > zero with RF gain wide open, and as the RF gain is decreased to zero > the meter deflection goes proportionally to 100, position of the AVC > switch has no effect. Resistance and voltage measurements around V110 > and V111 are normal, the tubes have been checked OK. The alignment is > dead on so far as I can tell, same indications on all bands, reception > of stations is fine, except the meter stays at zero. Any help on > where to go from here will be appreciated. The bench has the usual > test gear. > > Mike VE7MMH -- Al Klase - N3FRQ Jersey City, NJ http://www.skywaves.ar88.net/ ------------------------------ Message-ID: <60F8FC4EF36D43D680B80D5DC1C6D2FE@ToughBookLaptop> From: "WA3GIN" To: Old Tube Radios Subject: LOOKING FOR NC-100A Date: Thu, 15 Oct 2009 20:04:21 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0074_01CA4DD2.AF2AA940" This is a multi-part message in MIME format. ------=_NextPart_000_0074_01CA4DD2.AF2AA940 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Please contact direct. Thanks, dave wa3gin ------=_NextPart_000_0074_01CA4DD2.AF2AA940 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_0074_01CA4DD2.AF2AA940-- ------------------------------ Message-ID: From: "Michael Hardie" To: Old Tube Radios Cc: "Al Klase" Subject: R-388 Meter Problem 2 Date: Thu, 15 Oct 2009 18:48:21 -0700 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit Thanks Al for your suggestion, the problem is almost certainly AVC related. Using an RF generator at 10 Mcs a signal can be heard at a fraction of a microvolt at the antenna terminal, so the sensitivity is OK. But there's no AVC action until around 50 uV with the meter indication starting to deflect with the AVC action starting. I guess there are two possibilites, either AVC voltage is late being developed or the voltage is being drained off by a leaky cap or something similar. Are there any "usual suspects"? Mike VE7MMH ------------------------------ Message-ID: <24129362.1255658970468.JavaMail.root@elwamui-milano.atl.sa.earthlink.net> Date: Thu, 15 Oct 2009 22:09:30 -0400 (EDT) From: spr@earthlink.net To: Old Tube Radios Subject: Re: R-388 Meter Problem 2 Cc: Al Klase Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Mike, If the receiver has delayed AVC, the delay voltage is probably determined by a resistive divider. You might wish to check those resistors to see that they are still reasonably accurate. I've also had a radio with poor avc action and a strong signal overload problem in which a 20 pF mica cap from detector diode plate to ACV rectifier diode plate was essentially open. Good luck! /scott -----Original Message----- >From: Michael Hardie >Sent: Oct 15, 2009 9:48 PM >To: Old Tube Radios >Cc: Al Klase >Subject: R-388 Meter Problem 2 > >Thanks Al for your suggestion, the problem is almost certainly AVC related. >Using an RF generator at 10 Mcs a signal can be heard at a fraction of a >microvolt at the antenna terminal, so the sensitivity is OK. But there's no >AVC action until around 50 uV with the meter indication starting to deflect >with the AVC action starting. I guess there are two possibilites, either >AVC voltage is late being developed or the voltage is being drained off by a >leaky cap or something similar. Are there any "usual suspects"? > >Mike VE7MMH > ------------------------------ Message-ID: <4AD7E3FD.1030904@ar88.net> Date: Thu, 15 Oct 2009 23:09:49 -0400 From: Al Klase MIME-Version: 1.0 To: Old Tube Radios CC: Old Tube Radios Subject: Re: R-388 Meter Problem 2 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Mike, You may want to read this (my website): "RECOGNIZING AND DEALING WITH AVC PROBLEMS" http://www.skywaves.ar88.net/commrx/Maintenance/agc.htm Lod luck, Al Michael Hardie wrote: > Thanks Al for your suggestion, the problem is almost certainly AVC > related. Using an RF generator at 10 Mcs a signal can be heard at a > fraction of a microvolt at the antenna terminal, so the sensitivity is > OK. But there's no AVC action until around 50 uV with the meter > indication starting to deflect with the AVC action starting. I guess > there are two possibilites, either AVC voltage is late being developed > or the voltage is being drained off by a leaky cap or something > similar. Are there any "usual suspects"? > > Mike VE7MMH -- Al Klase - N3FRQ Jersey City, NJ http://www.skywaves.ar88.net/ ------------------------------ Message-Id: <57A8CA3F-E08F-4B12-BCA1-9F766E28FC8D@aol.com> From: mac To: Old Tube Radios Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v936) Subject: Re: R-388 Meter Problem 2 Date: Thu, 15 Oct 2009 21:14:03 -0700 Mike asks are there any "usual suspects?" Good question. The AGC circuit in the R388 (and 51J3) includes no less than two triodes, 11 resistors and 6 caps. In addition, almost impossible to trace out and visualize when looking at the schematic in the TM. A schematic for the 51J3 from Sams Photofact lays the circuit in a MUCH better way. Looking at the circuit, it appears that the rectified signal from the last IF stage would have to reach a peak value of 5 or 6 volts before AGC would cut in but don't know what this would equate to at the antenna input. Best to get hold of a manual (I only have schematics), check out just what the AGC specifications are and go from there. Dennis D. W7QHO Glendale, CA On Oct 15, 2009, at 6:48 PM, Michael Hardie wrote: > Thanks Al for your suggestion, the problem is almost certainly AVC > related. Using an RF generator at 10 Mcs a signal can be heard at a > fraction of a microvolt at the antenna terminal, so the sensitivity > is OK. But there's no AVC action until around 50 uV with the meter > indication starting to deflect with the AVC action starting. I > guess there are two possibilites, either AVC voltage is late being > developed or the voltage is being drained off by a leaky cap or > something similar. Are there any "usual suspects"? > > Mike VE7MMH ------------------------------ End of BOATANCHORS Digest 4292 ******************************