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161. Re: [Amps] SB-200 on WARC (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Wed, 23 Nov 2005 08:54:28 -0800; Possibly not on 17 M. But in any case you can check this with a grid dip meter. Temporarily solder a jumper across the choke and then (with power off, of course) look for a resonance. If it is within; /archives//html/Amps/2005-11/msg00459.html (7,016 bytes)
162. Re: [Amps] FL-21200B (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Tue, 06 Dec 2005 08:24:50 -0800; This sounds like a *real* VHF parasitic! Does the amplifier have parasitic suppressors? If so, check that the resistors aren't open or very high in value. -- 73, Vic, K2VCO Fresno CA http://www.qsl.n; /archives//html/Amps/2005-12/msg00048.html (7,491 bytes)
163. Re: [Amps] Emailing: hf_millinium (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Mon, 12 Dec 2005 08:22:43 -0800; It's very attractive. But it's a manually tuned and bandswitched amplifier for about $4K. Why do we need another one? I would like to see a completely automatic unit for no more than $3K. This almost; /archives//html/Amps/2005-12/msg00135.html (7,951 bytes)
164. Re: [Amps] Antenna traps (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Tue, 13 Dec 2005 14:29:02 -0800; You have two problems in making traps: current and voltage. I made some using 5KV doorknobs (for 160/80) and exploded the doorknobs at less than legal power. This was a result of heating as a result; /archives//html/Amps/2005-12/msg00154.html (8,102 bytes)
165. Re: [Amps] Designing the Cleanest Linear with RF Negative Feedback (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Thu, 15 Dec 2005 12:32:38 -0800; As a CW operator, I don't have to contend with wide SSB signals. But a big problem with strong local signals, both CW and SSB, is phase noise generated in the low level exciter stages. I suggest that; /archives//html/Amps/2005-12/msg00190.html (9,398 bytes)
166. Re: [Amps] Ohmite thick-film resistor L measurement (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Mon, 19 Dec 2005 16:47:25 -0800; Unless the reactance is greater than about 650 ohms, you should be able to use an MFJ or similar antenna analyzer -- it will tell you R and Z (or L). Am I missing something? -- 73, Vic, K2VCO Fresno; /archives//html/Amps/2005-12/msg00270.html (6,922 bytes)
167. Re: [Amps] Purpose of cathode resistor? (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Wed, 28 Dec 2005 09:33:14 -0800; My non-expert guess: if the fuse blows, it prevents the filament transformer secondary from rising to a very high positive voltage, possibly exceeding it's insulation rating. -- 73, Vic, K2VCO Fresno; /archives//html/Amps/2005-12/msg00353.html (7,602 bytes)
168. Re: [Amps] Calibrate a panel meter? (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Wed, 28 Dec 2005 12:28:50 -0800; Most older or surplus meters were calibrated for a steel panel. When you use them on an aluminum panel, they read wrong....I *think* they read low in a non-ferrous panel, but I can't swear to it (som; /archives//html/Amps/2005-12/msg00363.html (8,225 bytes)
169. Re: [Amps] Is solid Cu 600VAC house wire, good for tank toroids? (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Fri, 06 Jan 2006 07:40:37 -0800; Alex Eban wrote: ....or put a little differently: " we are too poor to afford cheap things". No, seriously, the E_H antenna is using PVC insulated house wire in its matching networks at the kilowatt; /archives//html/Amps/2006-01/msg00212.html (8,740 bytes)
170. Re: [Amps] Clean -vs- Unclean (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Mon, 09 Jan 2006 11:03:23 -0800; Yeah, and a car salesman once told me not to buy a particular model because it would generate too much interest on the part of attractive young ladies. Believe me, if it's being discontinued it's for; /archives//html/Amps/2006-01/msg00295.html (8,882 bytes)
171. Re: [Amps] new mobile amps from THP (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Wed, 11 Jan 2006 09:05:26 -0800; The FETs in the prototype that I saw were running at, I think, 60V. The unit had a built in AC supply and is rather large (but only weighs 36 pounds). I don't think it's suitable for mobile use. -- 7; /archives//html/Amps/2006-01/msg00341.html (8,345 bytes)
172. Re: [Amps] Input Network? (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Tue, 17 Jan 2006 20:56:03 -0800; Type 2 material is spec'd for use up to 10 MHz. A T68-6 would be more usual for 28 MHz. I think about 7 turns would be right (0.24 uh). Whether this is the cause of your problem, I'm not sure. If the; /archives//html/Amps/2006-01/msg00441.html (7,019 bytes)
173. Re: [Amps] Silly (use of) variac question (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Thu, 19 Jan 2006 21:15:14 -0800; The green wire should go to the chassis of the amp. It does not connect to the variac (unless the variac is in a box which you could ground too). The black and white wires go across the whole variac; /archives//html/Amps/2006-01/msg00474.html (7,812 bytes)
174. Re: [Amps] Silly (use of) variac question (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Thu, 19 Jan 2006 21:23:28 -0800; On re-reading this, I should add that it might be a good idea to connect the ground wire to the body of the variac (even if it isn't in a box) as well as the chassis of the amp. That way if there is; /archives//html/Amps/2006-01/msg00475.html (7,844 bytes)
175. Re: [Amps] Building or Buying a Tuned Input Network (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Mon, 23 Jan 2006 08:45:43 -0800; This idea keeps coming up. In my opinion, the *only* advantage of this solution (unless you are building a completely automatic amplifier a la 87A) is that it avoids the need to calculate input pi-ne; /archives//html/Amps/2006-01/msg00537.html (11,309 bytes)
176. Re: [Amps] Building or Buying a Tuned Input Network (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Mon, 23 Jan 2006 10:51:34 -0800; You're quite right. I thought about this, but made the suggestion that I did because it worked for me. These circuits are very non-critical, and if you can adjust the inductance and one capacitor it; /archives//html/Amps/2006-01/msg00543.html (10,479 bytes)
177. Re: [Amps] Building or Buying a Tuned Input Network (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Mon, 23 Jan 2006 11:24:18 -0800; There is some available inductance variation by squeezing/separating the turns on thre toroid. As I said, I had good luck making the input capacitor variable and the output fixed, but one could certa; /archives//html/Amps/2006-01/msg00547.html (9,930 bytes)
178. Re: [Amps] 3-500 / 4-400 cooling (09/10/2005) (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Sat, 28 Jan 2006 15:22:17 -0800; Something to keep in mind is that, in addition to insufficient cooling, one cause of this can be weakened clips in the tube socket, causing poor electrical contact. The pin gets hot, which may actual; /archives//html/Amps/2006-01/msg00651.html (7,318 bytes)
179. Re: [Amps] Super buy on the Bay! (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Fri, 03 Feb 2006 07:13:59 -0800; The guy claims that it works on 40-20-15-10 meters. Yeah, look at that 40-meter tank coil in there! -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ______________________________________________; /archives//html/Amps/2006-02/msg00052.html (7,737 bytes)
180. Re: [Amps] Pin Diodes (score: 1): Author: Vic K2VCO <vic@rakefet.com>; Date: Wed, 08 Mar 2006 09:14:49 -0800; I just want to add my own anecdotal evidence and prejudices here. I had an Alpha 86 (apparently updated) for a couple of years with absolutely no PIN diode problems, and I operate QSK cw exclusively,; /archives//html/Amps/2006-03/msg00210.html (8,966 bytes)

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