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21. Re: [Amps] drive power (score: 1): Author: rgroh@swbell.net; Date: Mon, 19 Mar 2007 20:50:45 -0700 (PDT); I think the problem being alluded to is a burst of RF (at full output) from the transmitter/transceiver which happens before the ALC can cut in and reduce it to the proper level. If the designer does; /archives//html/Amps/2007-03/msg00229.html (9,290 bytes)
22. Re: [Amps] Surge resistor (score: 1): Author: rgroh@swbell.net; Date: Wed, 21 Mar 2007 08:03:09 -0700 (PDT); Lost the original contents of your message but I think this might be some information of value regarding the surge resistor. I took a quick look at Eimac's 'Care and Feeding of Power Tubes' applicati; /archives//html/Amps/2007-03/msg00278.html (7,623 bytes)
23. Re: [Amps] Fw: Support For the Bean Pusher (score: 1): Author: rgroh@swbell.net; Date: Sun, 15 Apr 2007 18:32:26 -0700 (PDT); I'm not so sure the ' bean counters' should get all or even much of the blame (I also remember the Mantz TV story or urban folklore or whatever). I've been a design engineer for over 40 years - mostl; /archives//html/Amps/2007-04/msg00154.html (7,985 bytes)
24. Re: [Amps] New Guy, Old 813 amp (score: 1): Author: rgroh@swbell.net; Date: Fri, 27 Apr 2007 22:14:42 -0700 (PDT); Possibly because the unterminated input meant that feedback (i.e. output reflected back to the input port via the tube capacitance) was having a much greater effect than with a lower impedance tuned; /archives//html/Amps/2007-04/msg00353.html (13,250 bytes)
25. [Amps] Bird (like) 43 element available (1 W, 105-120 MHz) (score: 1): Author: Bob and Bettina Groh <rgroh@swbell.net>; Date: Thu, 28 Jun 2007 10:53:53 -0500; Prior to putting this plug in on EBAY, I thought I would see if anyone on the lists is interested. This is NOT a BIRD element (it lacks the Bird name, etc on the label) - no manufacturer is listed an; /archives//html/Amps/2007-06/msg00172.html (7,278 bytes)
26. [Amps] Looking for details on UTC Special Series transformer (seemessage) (score: 1): Author: Robert Groh <rgroh@swbell.net>; Date: Wed, 4 Jul 2007 07:03:39 -0700 (PDT); Cleaning up the basement some more and preparing to sell off some 4-1000A RF decks. I am looking for some idea of what the power transformer output current specifications might be. The only informati; /archives//html/Amps/2007-07/msg00028.html (6,842 bytes)
27. [Amps] Question about 4-1000A operation (score: 1): Author: Robert Groh <rgroh@swbell.net>; Date: Sat, 14 Jul 2007 22:43:17 -0700 (PDT); Well, I've got a bit of a problem and would like some opinions. Another ham tried out one of my 4-1000A tubes and reports the following: Filament fine, tube lights up fine He ran it with filament onl; /archives//html/Amps/2007-07/msg00236.html (6,733 bytes)
28. Re: [Amps] AL-811H maximum Ip (score: 1): Author: rgroh@swbell.net; Date: Wed, 22 Aug 2007 11:53:49 -0700 (PDT); A very nice explanation, Tom! A nice tutorial (which I am going to save). Bob, WA2CKY Jan, I strongly disagree with the advice you have been given. The short term current really doesn't matter at all; /archives//html/Amps/2007-08/msg00146.html (10,182 bytes)
29. Re: [Amps] SB-200 circuit breakers (score: 1): Author: rgroh@swbell.net; Date: Sun, 26 Aug 2007 16:07:20 -0700 (PDT); The breakers are thermally activated - the heat being generated by the current passing through the mechanism. The trip time is related to the current AND the time - with a big current, the breaker wi; /archives//html/Amps/2007-08/msg00194.html (8,655 bytes)
30. Re: [Amps] Load Pulling (score: 1): Author: rgroh@swbell.net; Date: Wed, 12 Sep 2007 08:17:32 -0700 (PDT); Oh, boy, this is a difficult question. First off, with a 2 MHz (i.e. period = 500 ns) narrow (i.e. 20 ns wide for a duty cycle of 4%), you have very rich harmonic generator with (if my memory serves; /archives//html/Amps/2007-09/msg00125.html (10,205 bytes)
31. Re: [Amps] HELP-SB-200 meter (score: 1): Author: rgroh@swbell.net; Date: Tue, 18 Sep 2007 07:31:39 -0700 (PDT); You can scan it into a photo image file and then print that. With the image, you can use some of the photo editing programs to clean up the image, invert black and white, etc, etc. As for the meter i; /archives//html/Amps/2007-09/msg00188.html (8,488 bytes)
32. Re: [Amps] HELP-SB-200 meter (score: 1): Author: rgroh@swbell.net; Date: Tue, 18 Sep 2007 07:59:34 -0700 (PDT); Excellent idea! I almost wish I had a meter to try your package on. Your program really seems to fit the bill - nice! 73 Bob Bob wrote (in part): Lot easier to use a program written to do the desired; /archives//html/Amps/2007-09/msg00191.html (7,810 bytes)
33. [Amps] FS: High voltage RF switches (score: 1): Author: Robert Groh <rgroh@swbell.net>; Date: Mon, 24 Sep 2007 19:42:34 -0700 (PDT); Cleaning up the basement and ran across an assortment of high voltage high current RF switches I used many years ago (early 70's) in some antenna coupler design development. I put some pictures up on; /archives//html/Amps/2007-09/msg00242.html (7,807 bytes)
34. Re: [Amps] looking for source of air flow switch (score: 1): Author: rgroh@swbell.net; Date: Sat, 29 Sep 2007 09:59:30 -0700 (PDT); Try google for 'surplus airflow switch' and you will get a lot of hits. They range from sophisticated to very simple (e.g. a sensitive microswitch with a blade where the blade sticks in the air strea; /archives//html/Amps/2007-09/msg00489.html (8,175 bytes)
35. Re: [Amps] Flashover and QSK board in TT Centurion (score: 1): Author: rgroh@swbell.net; Date: Mon, 1 Oct 2007 07:22:55 -0700 (PDT); I am certainly not an expert on HV and high power amps but I certainly could guess that you had an low impedance (e.g. an arc someplace - maybe in the tube? or across air between components or across; /archives//html/Amps/2007-10/msg00008.html (9,850 bytes)
36. Re: [Amps] CB Amps or full spectrum??? (score: 1): Author: rgroh@swbell.net; Date: Wed, 10 Oct 2007 09:46:12 -0700 (PDT); The tube one's would probably (i.e. 'might') have fewer harmonics. Part of that is because a tube amplifier is inherently a fairly highish Q due to matching from hiZ to 50 ohms. Transistor amplifiers; /archives//html/Amps/2007-10/msg00099.html (13,271 bytes)
37. Re: [Amps] TenTec Titan 425 HV filter caps (score: 1): Author: rgroh@swbell.net; Date: Wed, 10 Oct 2007 20:30:02 -0700 (PDT); I don't think you are overlooking anything - usually going to the equipment manufacturer costs you more because they have additional markups. My only recommendation would be that you use a 105 degC r; /archives//html/Amps/2007-10/msg00120.html (8,357 bytes)
38. Re: [Amps] Trimming the transmission line (score: 1): Author: rgroh@swbell.net; Date: Thu, 11 Oct 2007 19:19:59 -0700 (PDT); Yes. Although to generalize Barry's statements a bit, restricting the feedline to a certain length 'moves' the antenna impedance to a different impedance which is easier for the transmitter to handle; /archives//html/Amps/2007-10/msg00148.html (9,312 bytes)
39. Re: [Amps] EF Johnson Roller Inductor (score: 1): Author: rgroh@swbell.net; Date: Mon, 29 Oct 2007 21:24:35 -0700 (PDT); Bob, Take a look at this web page - Cardwell now makes the old EF Johnson line: http://www.cardwellcondenser.com/PAGES/md04g.html Lists only the standard parts and the 229-203-3 you refer to must hav; /archives//html/Amps/2007-10/msg00267.html (7,968 bytes)
40. Re: [Amps] Testing 8874s (score: 1): Author: rgroh@swbell.net; Date: Fri, 2 Nov 2007 12:52:40 -0700 (PDT); Barrie, There have a number of nice sources for information on hi-potting tubes etc. Here is one that addresses your question rather nicely: http://www.nd2x.net/k8cu-HV-tester.html 73 Bob, WA2CKY I w; /archives//html/Amps/2007-11/msg00027.html (10,562 bytes)

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