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101. Re: [Amps] Tubes vs. Solid State (was) Expert Amps 2K-FA: Any Opinions ? (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Sun, 29 Apr 2012 20:43:08 -0400; No, that's an apples to oranges comparison since you want a solid state amplifier to be capable of 65% "headroom". A well designed amplifier using 8 VRF-2933 or a pair of the Motorola/ Phillips 1200; /archives//html/Amps/2012-04/msg00266.html (16,132 bytes)
102. Re: [Amps] Tubes vs. Solid State (was) Expert Amps 2K-FA: Any Opinions ? (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Sun, 29 Apr 2012 21:35:27 -0400; 8 x VRF-2933 or 2 x 1200 W Motorola/Phillips "blocks" are not a 1200W amplifier. 2 x VRF-2933 do 600W brick on the key in the KPA-500. Both configurations I listed will do 2 KW CCS with reserve gain; /archives//html/Amps/2012-04/msg00273.html (13,249 bytes)
103. Re: [Amps] Tubes vs. Solid State (was) Expert Amps2K-FA:AnyOpinions? (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Mon, 30 Apr 2012 17:45:31 -0400; I doubt that ... the solid state devices would not appreciate the die temperatures with vapor phase cooling. However, a small radiator and closed water system would work very well. With a suitable pu; /archives//html/Amps/2012-04/msg00308.html (9,333 bytes)
104. Re: [Amps] SWR increase on SB-220 input (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Tue, 01 May 2012 09:57:53 -0400; You could also have cooked the slug in the coil or warped the coil form depending on the material. There is a fair amount of circulating current in those pi-networks when run off frequency. 73, ...; /archives//html/Amps/2012-05/msg00002.html (7,356 bytes)
105. Re: [Amps] Tubes vs. Solid State (was) Expert Amps2K-FA:AnyOpinions? (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Tue, 01 May 2012 11:31:03 -0400; That doesn't account for thermal resistance (heat transfer between substrate and water). Although the heat transfer issues from substrate to spreader/heatsink are the same in both cases, the issue s; /archives//html/Amps/2012-05/msg00007.html (12,117 bytes)
106. Re: [Amps] Tubes vs. Solid State (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Tue, 01 May 2012 18:16:32 -0400; The point here is that even 10 liters in a system with a small radiator and fan would be more than sufficient. Extend the hoses outside the shack and one has essentially noiseless cooling *and* remo; /archives//html/Amps/2012-05/msg00037.html (11,423 bytes)
107. Re: [Amps] Tubes vs. Solid State (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Wed, 02 May 2012 10:26:28 -0400; Yes, it would. Don't hold your breath ... all of them sere driven away by Measures and his sycophants because they refused to worship accept the heresy of nichrome. The attacks on W8JI were particul; /archives//html/Amps/2012-05/msg00054.html (11,371 bytes)
108. Re: [Amps] Tubes vs. Solid State (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Wed, 02 May 2012 10:29:13 -0400; What is the energy required for phase change? If it's too low you lose the benefit of the reduced boiling point. In addition, the vapors of both are explosive if you have a leak in the vicinity or a; /archives//html/Amps/2012-05/msg00055.html (10,602 bytes)
109. Re: [Amps] amps with vacuum pumps (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Wed, 02 May 2012 11:25:06 -0400; In most cases, heat pipe systems (and that's what one would have with an evacuated vapor system) require a secondary heat exchanger. The low pressure system moves the heat from where it's generated t; /archives//html/Amps/2012-05/msg00058.html (7,658 bytes)
110. Re: [Amps] SB 200 problem (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Fri, 04 May 2012 11:16:45 -0400; No, but you should be able to use a Schottkey diode it would have a similar low forward voltage drop. 73, ... Joe, W4TV _______________________________________________ Amps mailing list Amps@contest; /archives//html/Amps/2012-05/msg00172.html (9,806 bytes)
111. Re: [Amps] LDMOS Solid State Amplifiers (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Sun, 06 May 2012 13:44:45 -0400; I am honestly surprised that nobody has updated the Grandberg 4 x MFR150 design (EB 104) for the VRF-2933. That would make a "single board KW" for 90% Plus of all amateurs ... something within 0.5 dB; /archives//html/Amps/2012-05/msg00221.html (10,792 bytes)
112. Re: [Amps] Solid state amplifiers - big ones (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Tue, 08 May 2012 12:52:31 -0400; With compression greater than 3 dB for full power output it's certainly an IMD generator. To keep it linear and maintain reasonable IMD, the output power would need to be held below 7 KW if not sligh; /archives//html/Amps/2012-05/msg00240.html (8,036 bytes)
113. Re: [Amps] vl2000 (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Tue, 22 May 2012 23:21:56 -0400; No, the amplifier was ready ... Yaesu have decided that they can not sell the amplifier in the US at a profit. The Yen has increased about 20% vs. the US Dollar which would require selling the VL-200; /archives//html/Amps/2012-05/msg00317.html (7,181 bytes)
114. Re: [Amps] Amplified TV Antenna (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Fri, 06 Jul 2012 17:48:23 -0400; Significantly less impulse noise and interference. Also the allocation formulas favored coverage (higher permitted EIRP) in the low UHF channels and penalized coverage (actual signal levels failed t; /archives//html/Amps/2012-07/msg00053.html (10,155 bytes)
115. Re: [Amps] Amplified TV Antenna (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Fri, 06 Jul 2012 22:14:53 -0400; Even high VHF (Ch 7-13) suffers from noise and interference not present in the lower UHF channels. In addition, the propagation/allocation models were seriously flawed - many of those with high VHF; /archives//html/Amps/2012-07/msg00064.html (11,020 bytes)
116. Re: [Amps] Amplified TV Antenna (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Sat, 07 Jul 2012 08:53:27 -0400; Reception of DTV and NTSC is no different at the antenna. Channel scanning is channel scanning and using "cut to channel" Yagis is still "good engineering practice" in multi customer (cable, large ap; /archives//html/Amps/2012-07/msg00087.html (11,765 bytes)
117. Re: [Amps] Amplified TV Antenna (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Sat, 07 Jul 2012 12:03:17 -0400; Also far removed from amplifiers and their operation - more appropriate for a DTV antennas list. A twinlead folded dipole "FM Antenna" (88-108 MHz) is not very good on UHF TV (450-900 MHz). It has a; /archives//html/Amps/2012-07/msg00092.html (14,244 bytes)
118. Re: [Amps] Amplified TV Antenna (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Sat, 07 Jul 2012 14:44:45 -0400; If you are going to erect an external antenna, use the right antenna for the job. In mixed U/V environments, that's a U/V antenna - not a UHF bowtie that just "might" work on close-in VHF signals. If; /archives//html/Amps/2012-07/msg00099.html (17,292 bytes)
119. Re: [Amps] Amplified TV Antenna (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Sat, 07 Jul 2012 16:07:27 -0400; The digital cliff is the perfect vehicle for sloppy design since it allows a system to show a generally perfect picture one moment and nothing the next. It simply hides sloppy system design. Working; /archives//html/Amps/2012-07/msg00105.html (21,044 bytes)
120. Re: [Amps] Overdrive protection (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Thu, 26 Jul 2012 15:11:11 -0400; Of course there is but such a protection circuit would make the amp almost impossible to use with the many rigs have have a horrendous ALC spike on initial key-down. Many of the most commonly used r; /archives//html/Amps/2012-07/msg00277.html (9,274 bytes)

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