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41. [Amps] Hot Switching (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 15 Nov 2002 08:17:14 +0000; It depends on the combination of the transceiver, the amp and the voice. Basically it's a race against time between the transceiver and the amp. The amp gets its PTT from the transceiver, and it then; /archives//html/Amps/2002-11/msg00240.html (12,946 bytes)
42. [Amps] Output Safety Choke Value (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 15 Nov 2002 10:28:56 +0000; Probably when TV doorknob caps were pushed beyond their limits. But it is a real risk - although the probability is low, the consequences of B+ voltage getting onto the antenna line could be very nas; /archives//html/Amps/2002-11/msg00243.html (9,308 bytes)
43. [Amps] Hot Switching (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 15 Nov 2002 09:57:57 +0000; It seems to be a crossover from CB amps, via the "bricks" intended for amateur VHF-FM hand-helds that don't have a PTT output. But from there, RF-actuated switching seems to have trickled down into a; /archives//html/Amps/2002-11/msg00244.html (7,983 bytes)
44. [Amps] Hot Switching (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 15 Nov 2002 16:45:39 +0000; The Ameritron and some Alphas use PIN diode QSK, which is very fast and will work fine... if the transceiver timings will let it. I wonder if that's due to the very long spring arm - probably the har; /archives//html/Amps/2002-11/msg00256.html (10,167 bytes)
45. [Amps] SB220 T/R relay substitution (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 15 Nov 2002 16:25:35 +0000; On the 746 in all modes, it's about 12-14ms between the first key-down/PTT and the start of RF output. The HSEND/VSEND outputs on the DIN accessory sockets are the fastest for amp control, and they g; /archives//html/Amps/2002-11/msg00257.html (8,774 bytes)
46. [Amps] Re: Hot switching (score: 147): Author: Ian White <g3sek@ifwtech.co.uk> (Ian White); Date: Fri, 15 Nov 2002 23:09:49 +0000; Sorry, wrong callsign: www.k6xx.com -- 73 from Ian G3SEK; /archives//html/Amps/2002-11/msg00265.html (6,315 bytes)
47. [Amps] skin effect (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 4 Oct 2002 21:08:33 +0100; You're pretty much right. The skin effect keeps the RF current on the surface of the whole stranded bundle, so as each strand dives into the braid the current has to hop across onto strands that are; /archives//html/Amps/2002-10/msg00037.html (9,159 bytes)
48. [Amps] How light can you make a 500W amplifier? (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Mon, 14 Oct 2002 22:30:39 +0100; Take a look at www.uksmg.org and find your way to G3WOS's description of his 8877 DXpedition amp for 6m that fits into a pilot's carry-on case - complete with 115/230V mains supply. If he can manage; /archives//html/Amps/2002-10/msg00135.html (9,616 bytes)
49. [Amps] Vishay/Dale Glitch Resistors (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Thu, 24 Oct 2002 14:19:17 +0100; Try the Ohmite 20 series. Any physically long vitreous enamel type should be OK - connect 10 ohm or 15 ohm resistors in series to build up the required wattage and surge voltage capability. 20-30 ohm; /archives//html/Amps/2002-10/msg00248.html (7,533 bytes)
50. [Amps] Bird 1000H slug adjustment? (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Sat, 26 Oct 2002 23:30:45 +0100; Does anyone know how to adjust a Bird 1000H slug (1kW 2-30MHz)? It's reading only 400W when a known good slug reads 1000W, but there seem to be no trimpots or other adjustments inside. -- 73 from Ian; /archives//html/Amps/2002-10/msg00276.html (7,814 bytes)
51. [Amps] Bird 1000H slug adjustment? (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Sun, 27 Oct 2002 11:51:21 +0000; Thanks to everyone for all the suggestions. The good slug is not mine, so I can't open it up. However, this morning I finally got the brain into gear, and checked the DC resistances of the bad and go; /archives//html/Amps/2002-10/msg00279.html (9,387 bytes)
52. [Amps] Bird 1000H slug adjustment? (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Mon, 28 Oct 2002 08:45:15 +0000; My guess too, though it may have been a special for Bird. I'll try that. Good point. In the 1000H there's a fixed 2.102K resistor in series with a 20.3K (where do they get these weird values?). Doesn; /archives//html/Amps/2002-10/msg00289.html (9,163 bytes)
53. [Amps] Glitch resistors (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Sun, 1 Sep 2002 11:02:00 +0100; The metal clad power resistors are not suitable for glitch-resistor service. The resistor-to-case voltage rating isn't high enough, and the metal case greatly increases the risk of end-to-end arcing; /archives//html/Amps/2002-09/msg00001.html (8,994 bytes)
54. [Amps] Glitch resistors (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Mon, 2 Sep 2002 14:09:45 +0100; Any will do from the glitch point of view, but the 50R ones will drop less voltage and generate less heat than the 75/80R ones. 50R is probably on the high side of the normal range of values, unless; /archives//html/Amps/2002-09/msg00011.html (8,200 bytes)
55. [Amps] Computer Grade Electrolytic Capacitors vs. Radial (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Thu, 5 Sep 2002 13:07:55 +0100; I haven't checked that example, but one "gotcha" in the Duncan program is that the default results in the tables include the power-on cycles where current can be very high. The solution is to set the; /archives//html/Amps/2002-09/msg00036.html (9,401 bytes)
56. [Amps] Computer Grade Electrolytic Capacitors vs. Radial (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Thu, 5 Sep 2002 23:49:11 +0100; I was alerted by some totally screwy results in another area. Seems right to me. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/; /archives//html/Amps/2002-09/msg00043.html (8,648 bytes)
57. [Amps] al80a (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 2 Aug 2002 09:08:54 +0100; Take care about the glitch diode. In an SB-1000 (same animal) that someone else had "pre-repaired", I had weird meter readings on 160m until the glitch diode was replaced with a 1N5408. It turned out; /archives//html/Amps/2002-08/msg00015.html (10,981 bytes)
58. [Amps] al80a (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Fri, 2 Aug 2002 23:39:32 +0100; I didn't even try. If you think about it, such a measurement is well-nigh impossible in that location, which is very hard to get to and bathed in an intense RF field. You've also mentioned several ti; /archives//html/Amps/2002-08/msg00030.html (12,196 bytes)
59. [Amps] al80a (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Sat, 3 Aug 2002 08:53:27 +0100; While rooting around inside the SB-1000, I checked the carbon resistor in the paralytic choke... good as new. The RF choke and bypass caps were there as standard. Since the screwy meter readings were; /archives//html/Amps/2002-08/msg00038.html (10,411 bytes)
60. [Amps] al80a (score: 147): Author: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK); Date: Sat, 3 Aug 2002 15:31:25 +0100; I'm aware of that, so I unsoldered the resistor and measured the value... good as new. There are thousands of amps, of many different kinds, that seem to work fine with 0.001uF. That evidence has a l; /archives//html/Amps/2002-08/msg00041.html (8,277 bytes)

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