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81. Re: [Amps] A One Tube Radio (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Mon, 21 Jan 2008 15:36:03 -0500; This is probably not the right place to discuss the nanotube receiver. However, the resonant properties of nanotubes are being used in the anti-cancer work by K3TUP as profiled in the current issue o; /archives//html/Amps/2008-01/msg00136.html (9,777 bytes)
82. Re: [Amps] MLA-2500 (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Fri, 25 Jan 2008 12:06:05 -0500; The issue that kills the tubes in that amp is over drive and overheating the grid, not "parasitics." Due to the transverse cooling the 8875 is rated for 300 watts plate dissipation (not 400 like the; /archives//html/Amps/2008-01/msg00180.html (11,469 bytes)
83. Re: [Amps] RF Parts Channel; Television Broadcast Equipment (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Mon, 18 Feb 2008 16:06:02 -0500; There will be very little of use coming out of the old TV transmitters. Even the tube transmitters have been solid state to the final for many years - typically 1200 - 1600 watts at VHF (feeding tetr; /archives//html/Amps/2008-02/msg00121.html (10,421 bytes)
84. Re: [Amps] IC2KL ACC cable (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sat, 8 Mar 2008 12:13:59 -0500; They are Molex. I don't have the exact part numbers any more but they are available from Newark Electronics. If you have the 2KL/AT500 on the bench you will be able to measure the connectors and get; /archives//html/Amps/2008-03/msg00077.html (8,662 bytes)
85. Re: [Amps] Need source of connectors and/or cables forYaesu FT-1000D-to-FL-7000 rig (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Thu, 20 Mar 2008 11:18:57 -0400; Note, the FT-1000D uses the DIN8/262 and not the more common DIN8 plug. The FL-7000 requires a Molex connector details (Molex part number) for the plug and pins are available at www.n4ats.com. In add; /archives//html/Amps/2008-03/msg00186.html (8,912 bytes)
86. Re: [Amps] ALS-600 Blowing Out Finals (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sat, 29 Mar 2008 10:01:36 -0400; Many of the "modern" transceivers have excess IF gain and use the ALC circuit for power control. Due to time constant issues (the manufacturer wants the radio to reach full power instantly) these tr; /archives//html/Amps/2008-03/msg00333.html (9,262 bytes)
87. Re: [Amps] Replacing 811A with 572B (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Wed, 9 Apr 2008 20:23:40 -0400; Why waste the money ... four 572Bs are half again to twice the price of four 811s. The 572B will not provide any more gain or power output than the 811 unless you modify the power supply for about 40; /archives//html/Amps/2008-04/msg00122.html (8,712 bytes)
88. Re: [Amps] Replacing 811A with 572B (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Wed, 9 Apr 2008 22:58:44 -0400; If the AL-811A plate voltage runs that high it is exceeding the "Maximum Plate Voltage" rating for the 811A tube and is a bad design. The RCA data sheet calls for 1500 V maximum in ICAS service and; /archives//html/Amps/2008-04/msg00129.html (11,484 bytes)
89. Re: [Amps] Replacing 811A with 572B (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Thu, 10 Apr 2008 00:12:49 -0400; I consider the question to be one of replacing 811A with 572B in general. Except for the unique case where the high voltage is above the 811's ratings, the answer is still "not worthwhile." The fila; /archives//html/Amps/2008-04/msg00133.html (11,877 bytes)
90. Re: [Amps] Replacing 811A with 572B (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Thu, 10 Apr 2008 00:22:46 -0400; The only difference is plate dissipation. Operated at 1250 volts on the plate and not overdriven, 4 x 811A have more than enough plate dissipation for service at 800W PEP output. The most likely fai; /archives//html/Amps/2008-04/msg00134.html (12,601 bytes)
91. Re: [Amps] Tube suggestion needed - 6 and/or 2M ~500W level with800-1kv on plate? (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sat, 21 Jun 2008 18:04:45 -0400; If you really want to use the GLA-1000 on six meters consider converting it as a monoband amplifier with EL-509s. Yes, the 509 is a sweep tube but Far Circuits has a replacement circuit board, you sh; /archives//html/Amps/2008-06/msg00162.html (13,184 bytes)
92. Re: [Amps] Bill Orr comment (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Wed, 23 Jul 2008 17:50:14 -0400; Depends on what Orr means by the statement ... if he means that the output (amplifier + feed through power) will be at least twice the power dissipated in the tube, he's probably accurate at "two ti; /archives//html/Amps/2008-07/msg00220.html (11,679 bytes)
93. Re: [Amps] Dentron MLA2500 SWR Question (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Fri, 1 Aug 2008 18:26:33 -0400; While you're in the area of the bandswitch also look at the padding capacitors ("doorknobs") since they are notorious for thermal drift with high current. A bad padder would also be consistent with; /archives//html/Amps/2008-08/msg00006.html (15,961 bytes)
94. Re: [Amps] IMD and driving power (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sun, 31 Aug 2008 10:00:00 -0400; This is one of those "general rules" that is very wrong when it comes to solid state transceivers. Almost all modern power transistors have a "saddle shaped" IMD curve. When power output is reduced; /archives//html/Amps/2008-08/msg00192.html (8,954 bytes)
95. Re: [Amps] IMD and driving power (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Tue, 9 Sep 2008 10:20:53 -0400; That's true enough. Unfortunately, as you also point out in your presentation, most transceivers do not offer 24, 32, or 48 volt amplifiers capable of 200 in class B and 50 to 60 watts in class A. A; /archives//html/Amps/2008-09/msg00076.html (11,992 bytes)
96. Re: [Amps] Ameritron AL-82 Questions (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Mon, 15 Sep 2008 01:02:58 -0400; The one reported issue with all of the Ameritron amps is some concern with the output Circuit and RTTY. There have been a few reports about the 80 meter coil overheating and deforming when run at ful; /archives//html/Amps/2008-09/msg00138.html (10,817 bytes)
97. Re: [Amps] SB-220 saga continues (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sun, 9 Nov 2008 10:20:04 -0500; The keying line (PTT relay) in the SB-220 is +120 V DC. The contacts of the "Linear" or "Send" relays in most transceivers can not handle the voltage and current "spike" generated by the high voltage; /archives//html/Amps/2008-11/msg00069.html (10,386 bytes)
98. Re: [Amps] SB-220 saga continues (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sun, 9 Nov 2008 12:24:10 -0500; Nearly all of the current crop of transceivers (including FT-9000, FT-2000, IC-756ProIII, IC-746Pro, TS-2000, TS-870, TS-570, etc.) still include an optional relay output. However, they are generall; /archives//html/Amps/2008-11/msg00073.html (13,703 bytes)
99. Re: [Amps] L4B Keying (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Thu, 13 Nov 2008 11:00:05 -0500; The Dahl catalog shows the filament transformer having 5VCT and 22 V secondaries. With a half-wave rectifier, capacitor filter and 2.2K bleeder, I would estimate the voltage on the coil to be around; /archives//html/Amps/2008-11/msg00151.html (7,498 bytes)
100. Re: [Amps] rx noise? (score: 1): Author: "Joe Subich, W4TV" <w4tv@subich.com>; Date: Sat, 6 Dec 2008 13:53:37 -0500; Check the bias switch (relay, transistor, ?). If cutoff is not being applied in receive, the tube will generate wideband noise ("shot" noise). 73, ... Joe, W4TV ______________________________________; /archives//html/Amps/2008-12/msg00126.html (10,909 bytes)

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