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Total 130 documents matching your query.

101. Re: [Amps] HV MOSFETs for RF (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Wed, 10 May 2017 14:31:56 +0000 (UTC)
"Problem is, the typical 140 db MDS of today's xcvrs is rendered useless, since the noise floor in urban areas is way higher than that." Yes, this is why those of us in rural areas need an amp more t
/archives//html/Amps/2017-05/msg00105.html (9,339 bytes)

102. Re: [Amps] HV MOSFETs for RF (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Thu, 11 May 2017 17:26:35 +0000 (UTC)
What is that flaw in most 100W radios, Manfred? 73, Cathy N5WVR _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2017-05/msg00111.html (8,696 bytes)

103. Re: [Amps] new amp race (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 21 May 2017 03:23:17 +0000 (UTC)
I'd blame this more on sunspot lows than egos. Egos have always been with us, but we are seeing unprecedented poor solar conditions. Every cycle since 1958 has been weaker than the one before. Even
/archives//html/Amps/2017-05/msg00196.html (9,642 bytes)

104. Re: [Amps] new amp race (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 21 May 2017 18:27:34 +0000 (UTC)
Sure you can. You have a certain amount of $$$ (or whatever your local currency is) to spend on improving your station. Each dollar can be spent on raising transmit power, raising antenna gain, or ra
/archives//html/Amps/2017-05/msg00212.html (9,270 bytes)

105. Re: [Amps] new amp race (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 21 May 2017 18:50:57 +0000 (UTC)
Because it feels like "do as I say, not as I do." A person who owns an amp is telling other hams not to buy one. If it's so useless, why does the poster have one himself? If the advice were "put up
/archives//html/Amps/2017-05/msg00213.html (9,580 bytes)

106. Re: [Amps] new amp race (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 21 May 2017 19:01:52 +0000 (UTC)
90% of my operation is at night. Retirement is a long way away. 20 is occasionally great, but I spend far more time on 40, 80, and 160, and I'd like to spend more time on 30. Bingo, Jim has nailed it
/archives//html/Amps/2017-05/msg00214.html (10,794 bytes)

107. Re: [Amps] new amp race (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 21 May 2017 23:34:45 +0000 (UTC)
Bill, My QTH is riddled with antennas, so I'm hardly going to object to advice to build a few more. :-) There are pieces of a 2-meter Quagi and a tribander VHF/UHF quad out on the workbench right now
/archives//html/Amps/2017-05/msg00229.html (9,706 bytes)

108. Re: [Amps] new amp race (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 21 May 2017 23:41:23 +0000 (UTC)
The 10 dB assumed that it was replacing an antenna that wasn't high enough to perform well, so some of that gain comes from the tri-bander pattern, and some from the 70 ft height. But that requires
/archives//html/Amps/2017-05/msg00230.html (8,841 bytes)

109. Re: [Amps] Tube amps are not a thing of the past (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Mon, 5 Jun 2017 12:43:41 +0000 (UTC)
Yes, ham gear needs to be based on the RF PA equivalent of the 2N2222 and 2N3055; devices that have many uses, are fully mature, and won't be readily obsoleted by new tech. We may need to see solid
/archives//html/Amps/2017-06/msg00037.html (8,365 bytes)

110. Re: [Amps] LDMOS availability (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Mon, 5 Jun 2017 18:49:38 +0000 (UTC)
Just because people keep buying them doesn't mean they'll continue to be made. Many products are replaced with a next-generation, not-necessarily-backward-compatible product while demand is still str
/archives//html/Amps/2017-06/msg00055.html (7,929 bytes)

111. Re: [Amps] 3-500Z cool down time (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Tue, 6 Jun 2017 14:04:07 +0000 (UTC)
Given that ceramic tubes appear to last longer on the shelf with less leakage than glass, it's a shame that there isn't a ceramic tube in the price/performance range of the 3-500Z. It would be well w
/archives//html/Amps/2017-06/msg00079.html (10,351 bytes)

112. Re: [Amps] Nice new japanese tube amp (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Tue, 6 Jun 2017 14:07:32 +0000 (UTC)
Jim has a different idea of a "bargain" than I do. :-) $10K for a ham radio item is enough to make me gasp for air. _______________________________________________ Amps mailing list Amps@contesting.c
/archives//html/Amps/2017-06/msg00080.html (7,192 bytes)

113. Re: [Amps] 3-500Z cool down time (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Tue, 6 Jun 2017 15:14:26 +0000 (UTC)
Kim, It's generally recognized that glass tubes have poor shelf life due to slow leakage. I have heard many reports of this from people I trust. They will last much longer if the plate gets hot at le
/archives//html/Amps/2017-06/msg00082.html (12,221 bytes)

114. Re: [Amps] 3-500Z cool down time (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Tue, 6 Jun 2017 16:52:56 +0000 (UTC)
The point is that you can't count on them working after prolonged storage. You may get lucky, or not. So, I think it depends on the individual tube.   73 Charlie N8RR   ______________________________
/archives//html/Amps/2017-06/msg00090.html (8,515 bytes)

115. Re: [Amps] LDMOS availability (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Wed, 7 Jun 2017 13:20:06 +0000 (UTC)
That was my initial reaction too, but several people on the list pointed out a range of commercial markets where linear operation is important, so this may be less of an issue than I thought. 73, Cat
/archives//html/Amps/2017-06/msg00107.html (8,483 bytes)

116. Re: [Amps] Ten-Tec Titan 10 Meter Input SWR (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 11 Jun 2017 14:27:00 +0000 (UTC)
Bill, I'm puzzled at the idea that changing "the impedance the transceiver sees" wouldn't affect SWR. Isn't SWR the ratio between the impedance seen at the measurement point vs. the desired impedance
/archives//html/Amps/2017-06/msg00150.html (9,247 bytes)

117. Re: [Amps] Ten-Tec Titan 10 Meter Input SWR (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Sun, 11 Jun 2017 14:35:31 +0000 (UTC)
Luck has nothing to do with it. The calculation is described in Chapter 26 of the ARRL Antenna Book, "Coupling the Line to the Antenna". The material originally came from an article on series-section
/archives//html/Amps/2017-06/msg00151.html (8,342 bytes)

118. Re: [Amps] SB220 step start blows fuses (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Mon, 26 Jun 2017 12:28:59 +0000 (UTC)
Any time the fan doesn't start immediately after power-up, shut down your SB-220 **immediately**. You may have a short, and if the breakers/fuses don't blow, you will smoke the power supply very quic
/archives//html/Amps/2017-06/msg00274.html (8,088 bytes)

119. Re: [Amps] Machlett 3-500z (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Mon, 24 Jul 2017 15:50:52 +0000 (UTC)
The general rule today is that you can either new tubes from China, or New Old Stock (NOS) leftover from product in the US, Russia, or elsewhere. Brands don't matter much in this world. At most, they
/archives//html/Amps/2017-07/msg00095.html (8,041 bytes)

120. [Amps] Amplifier lifetime (score: 1)
Author: Catherine James <catherine.james@att.net>
Date: Wed, 4 Oct 2017 15:05:28 +0000 (UTC)
I expect my SB-220 will be operating for my entire ham radio lifetime. And I'm not retired, so that will be decades. I fire it up at least once a month to keep it gettered. I expect my AL-811H will a
/archives//html/Amps/2017-10/msg00044.html (8,258 bytes)


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