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References: [ +from:4cx250b@miamioh.edu: 327 ]

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281. Re: [Amps] W8ZR Autotune Amplifier Progress Report (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Sat, 26 Dec 2020 07:39:52 -0800; Having used both gear-reduced stepper motors and rotary solenoids on a hard-to-turn band switch, I find the rotary solenoid is easier to implement, but the stepper motor solution is the more elegant; /archives//html/Amps/2020-12/msg00069.html (16,450 bytes)
282. Re: [Amps] Distilled water in a dummy load ? (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Sun, 21 Feb 2021 12:46:18 -0800; My instinct is that mineral oil would be a better coolant than distilled water, with no corrosion issues. You can buy it at any pharmacy, and while it isnt rated at quite as high a temperature as tra; /archives//html/Amps/2021-02/msg00026.html (9,168 bytes)
283. Re: [Amps] QRO HF2000 input SWR adjustments (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Sun, 14 Mar 2021 17:23:51 -0700; Sounds like its been tweaked for CW operation. It shouldnt be hard to retune the inputs for a compromise at the middle of each band. So long as your transceiver can handle a 2:1 mismatch, there shoul; /archives//html/Amps/2021-03/msg00005.html (7,752 bytes)
284. Re: [Amps] Looking for Alpha 87A expertise (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Tue, 16 Mar 2021 08:42:58 -0700; As an addendum to Pauls informative post, my own QSK circuit (QST June 2015, and http://www.w8zr.net/homebrew/) has a lock-on feature that keeps the amplifier locked on-line until RF from the exciter; /archives//html/Amps/2021-03/msg00017.html (11,609 bytes)
285. Re: [Amps] QRO HF2000 tank coil Q question (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Tue, 23 Mar 2021 16:45:56 -0400; Jim raises an issue which has troubled me lately, and that is whether the added expense and headaches required to build a bandswitched pi-L tank circuit is justified by the modest gain in harmonic at; /archives//html/Amps/2021-03/msg00033.html (9,067 bytes)
286. Re: [Amps] 89 Alpha schematic (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Sun, 4 Apr 2021 17:50:15 -0700; Clearly theres an error in the schematic. So far as I can tell, the fuse should be in series with R10, the surge-limiting resistor. Its purpose is not to protect R10, but to protect the amplifier in; /archives//html/Amps/2021-04/msg00012.html (9,492 bytes)
287. Re: [Amps] Alpha 87A Won't Transmit (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Wed, 7 Apr 2021 18:50:41 -0400; In my experience, UHF connectors, especially spices, often develop corrosion and intermittent connections on the inner conductor. Ive discovered that if I undo a PL259 and look at the mating S0239, I; /archives//html/Amps/2021-04/msg00019.html (7,856 bytes)
288. Re: [Amps] Alpha 87A Won't Transmit (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Thu, 8 Apr 2021 09:44:58 -0400; Thanks, Rob, thats a very informative link. After years Of arguing against crimp connectors, Ive finally been persuaded to change my mind. What did the trick are the next generation PL259 connectors; /archives//html/Amps/2021-04/msg00023.html (9,136 bytes)
289. Re: [Amps] Topband: PL259 type connectors for RG11 (score: 1): Author: Jim Garland <4cx250b@miamioh.edu>; Date: Thu, 8 Apr 2021 15:18:58 -0600; I agree completely with Frank about the virtues of the DXE-PL259CS8U Next Generation UHF PL259 connectors. (Actually, I pretty much always agree with Frank, whatever the topic.) One thing I especiall; /archives//html/Amps/2021-04/msg00032.html (10,790 bytes)
290. [Amps] PL259 Connector Debate (score: 1): Author: Jim Garland <4cx250b@miamioh.edu>; Date: Fri, 9 Apr 2021 15:17:35 -0600; Hi Tim and the group, There are many ways to skin a cat, and I applaud your technical prowess (and patience!)in successfully assembling hundreds of PL259 connectors. That said, many of us still strug; /archives//html/Amps/2021-04/msg00059.html (8,849 bytes)
291. Re: [Amps] Alpha 87A Power Supply Question (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Tue, 4 May 2021 07:24:58 -0700; I believe the appropriate hookup depends on the circuitry. As already noted, the guiding principle is that return current should always be through neutral, and never through ground. This is an import; /archives//html/Amps/2021-05/msg00008.html (19,070 bytes)
292. Re: [Amps] Alpha 87A Power Supply Question (score: 1): Author: Jim Garland <4cx250b@miamioh.edu>; Date: Tue, 4 May 2021 16:59:24 -0600; This is an interesting discussion of a topic that recurs frequently. I agree with Jim K9YC that house wiring should preferably bond the Neutral circuit to Ground at the service entrance, and nowhere; /archives//html/Amps/2021-05/msg00016.html (16,111 bytes)
293. Re: [Amps] Alpha 87A Power Supply Question (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Wed, 5 May 2021 17:01:19 -0700; Hi Jeff and Jim, I happily defer to your greater knowledge of electrical codes, about which I know very little. I also understand that amateur equipment powered off 240VAC should have four conductor; /archives//html/Amps/2021-05/msg00022.html (19,235 bytes)
294. Re: [Amps] Swan Mark 1 on 160 meters (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Wed, 30 Jun 2021 18:51:52 -0400; Normally, toroids are self-shielding, which means they are hard to couple into inductively. In a bandswitched amplifier, the inductive loop coupling into the toroid is normally created by the wiring; /archives//html/Amps/2021-06/msg00036.html (9,091 bytes)
295. [Amps] Vacuum Relay Question (score: 1): Author: Jim Garland <4cx250b@miamioh.edu>; Date: Sun, 25 Jul 2021 10:17:30 -0600; I'm repairing lightning damage to a 160m matching network at the base of my 80m 1/4 wave vertical, and am using a Kilovac H-16 (basically same as a Jennings RB3) DPDT vacuum relay in the network, wh; /archives//html/Amps/2021-07/msg00070.html (7,313 bytes)
296. Re: [Amps] Vacuum Relay Question (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Mon, 26 Jul 2021 07:29:22 -0700; Im open to your suggestion, Rob, but dont understand it. What do you mean by low v high current setup? The matching network is in a very compact weatherproof enclosure at the base of a 70 foot self-s; /archives//html/Amps/2021-07/msg00072.html (9,107 bytes)
297. Re: [Amps] Vacuum Relay Question (score: 1): Author: Jim Garland <4cx250b@miamioh.edu>; Date: Mon, 26 Jul 2021 11:13:14 -0600; Hi Rob, I agree with everything you say. I'm afraid didn't make clear the purpose of my matching network. It does just what you suggest: when on 80m circuit routes the transmitter directly to the b; /archives//html/Amps/2021-07/msg00074.html (8,877 bytes)
298. Re: [Amps] Drifting Power (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Sat, 16 Oct 2021 09:23:11 -0700; Im not aware of any vacuum tube RF power amplifiers that are sensitive to room temperature changes. However, if fixed load capacitors heat up under full RF power, a frequent occurrence, that can affe; /archives//html/Amps/2021-10/msg00072.html (10,592 bytes)
299. Re: [Amps] Triode Amps (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Fri, 3 Dec 2021 05:44:54 -0800; My favorite too. One of my Eimac 8877s has a 1974 date code, still full output. 73, Jim w8zr Sent from my iPhone _______________________________________________ Amps mailing list Amps@contesting.com; /archives//html/Amps/2021-12/msg00033.html (9,468 bytes)
300. Re: [Amps] Triode Amps (score: 1): Author: MU 4CX250B <4cx250b@miamioh.edu>; Date: Fri, 3 Dec 2021 07:05:31 -0800; I'm using a Chinese 8877 in an Alpha 9500, and am very satisfied with it. I've compared it to an Eimac 8877 and find the performance almost identical, the sole difference being that the Chinese versi; /archives//html/Amps/2021-12/msg00035.html (8,919 bytes)

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