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Total 161 documents matching your query.

81. Re: [Amps] low band PA (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Sat, 23 Aug 2014 08:25:02 +0100
Also try http://www.wireless.org.uk/throb.htm, and there's a link there to pictures of an amp by DL4XX. In the G3YMX circuit, it is better to have separate bias adjustment for each transistor. Steve
/archives//html/Amps/2014-08/msg00062.html (7,377 bytes)

82. Re: [Amps] AL80B power meter not working (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Thu, 13 Nov 2014 08:17:22 +0000
A minor point, not really relevant to your test - 1N914 is a 'regular' diode like 1N4148 except that 1N4148 has lower leakage. I mention it only to avoid disappointment should someone grab a 1N914 fo
/archives//html/Amps/2014-11/msg00027.html (7,656 bytes)

83. Re: [Amps] Linearization problem (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Thu, 04 Dec 2014 22:40:15 +0000
And a bonus question: Do you think that the phase distortion in such a class-A-AB-C-E amplifier will be bad enough to still cause poor IMD performance, even while the envelope linearity is excellent?
/archives//html/Amps/2014-12/msg00031.html (8,578 bytes)

84. Re: [Amps] Alpha Input SWR (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Sat, 10 Jan 2015 09:07:36 +0000
For a fixed impedance Hardy's comment is correct. Changing the feeder length alters the phase but not the SWR (ok, there's caveats but they don't apply in an ordinary ham station). If your SWR readin
/archives//html/Amps/2015-01/msg00019.html (7,683 bytes)

85. Re: [Amps] really outrageous amps (score: 1)
Author: Steve <g8gsq72@gmail.com>
Date: Wed, 21 Jan 2015 18:08:07 +0000
Don't overlook the first item here: http://www.qsl.net/yu1aw/Misc/xb_pa.htm Steve http://bear-el.com/ You can get a lot of ideas and how he did various concepts. Scroll down a bit for the master list
/archives//html/Amps/2015-01/msg00194.html (6,800 bytes)

86. Re: [Amps] GS35B GASSY OR ARCING (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Sun, 01 Mar 2015 16:37:48 +0000
My experience was exactly the same. Steve Good news. Dr Alex Gavva is sending me a replacement. He stands behind his tubes and is obviously a good man to deal with. Bob. W4AOS _______________________
/archives//html/Amps/2015-03/msg00002.html (6,487 bytes)

87. Re: [Amps] 4Z4RB HF pallet information (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Tue, 17 Mar 2015 08:19:48 +0000
Is SFR a typo? SRF is a prefix used by Motorola for custom parts. I don't know if Freescale use it for their new generation FETs, or whether M/A Com carried on using it for the legacy line they took
/archives//html/Amps/2015-03/msg00033.html (7,454 bytes)

88. Re: [Amps] more - oil bath GS-35b (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Mon, 30 Mar 2015 08:27:38 +0100
Make sure you don't create a situation akin to a Van de Graaff generator where oil goes through 3kV at the anode, then through insulated pipes to the cooler. A place I worked many years ago trialled
/archives//html/Amps/2015-03/msg00080.html (7,569 bytes)

89. Re: [Amps] more - oil bath GS-35b (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Mon, 30 Mar 2015 22:44:53 +0100
Ooops, that was meant to be 4CX15000. Fluid cooling is efficient, but not that good! Make sure you don't create a situation akin to a Van de Graaff generator where oil goes through 3kV at the anode,
/archives//html/Amps/2015-03/msg00084.html (7,580 bytes)

90. Re: [Amps] 3CX800 grid collet or SK1900 (score: 1)
Author: Steve <g8gsq72@gmail.com>
Date: Mon, 15 Jun 2015 16:18:15 +0100
The grid ring on a 3CX800 is the same size as the screen ring on a 4CX250 so you could dismantle a '250 base to get one. I've done neutralising with grid fingers at UHF but not seen it needed at 2m.
/archives//html/Amps/2015-06/msg00029.html (8,546 bytes)

91. Re: [Amps] Understanding S Parameters (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Wed, 17 Jun 2015 22:17:51 +0100
As it's a 1W transistor, the input capacitance is likely to be less than 1-5nF. Don't get too hung up about three decimal places of accuracy, reflection coefficients anywhere near 1 are prone to huge
/archives//html/Amps/2015-06/msg00046.html (10,855 bytes)

92. Re: [Amps] Amp output power (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Mon, 24 Aug 2015 22:31:06 +0100
If you check at http://www.g8wrb.org/triodes/ there's several data sheets. I came across a copy of the one with 1370W output spec. and copied it to David to host. I believe there was a spell where FC
/archives//html/Amps/2015-08/msg00084.html (9,443 bytes)

93. Re: [Amps] N panel connector screws (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Sun, 04 Oct 2015 08:49:16 +0100
M3 if you're outside the US. Steve What size screws and nuts do typical panel mount female N and UHF connectors use? _______________________________________________ Amps mailing list Amps@contesting.
/archives//html/Amps/2015-10/msg00007.html (7,404 bytes)

94. Re: [Amps] Question about SPE 1.3K-FA amplifier (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Sun, 08 Nov 2015 08:38:10 +0000
Most likely the 'one' transistor is actually one package with two transistors inside it - for example BLF578xr. Steve I notice the SPE 1.3K-FA amplifier is using a single LDMOS transistor to achieve
/archives//html/Amps/2015-11/msg00019.html (8,567 bytes)

95. Re: [Amps] Question about SPE 1.3K-FA amplifier (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Sun, 15 Nov 2015 10:36:35 +0000
Varying bias can optimise IMD at low and medium power levels but once you hit saturated output, I think it has relatively little effect. Steve _______________________________________________ Amps mai
/archives//html/Amps/2015-11/msg00095.html (8,633 bytes)

96. [Amps] Amplifier components (score: 1)
Author: Steve <g8gsq72@gmail.com>
Date: Wed, 18 Nov 2015 17:00:40 +0000
A friend has some health problems and is looking to clear some parts from unstarted projects: 2 x 3CX3000F7 Custom wound transformers: Filament - primary tapped 220-250V, secondary 3.75-0-3.75 at 52A
/archives//html/Amps/2015-11/msg00115.html (7,079 bytes)

97. Re: [Amps] Link to the Ugly Amp (score: 1)
Author: Steve Thompson <g8gsq72@gmail.com>
Date: Mon, 30 Nov 2015 21:45:15 +0000
I have a PSU that matches yours, but you beat me hands down on the amplifier :-) Steve _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.co
/archives//html/Amps/2015-12/msg00003.html (6,840 bytes)

98. Re: [Amps] 8875 (score: 1)
Author: Steve <g8gsq72@gmail.com>
Date: Thu, 3 Dec 2015 18:31:30 +0000
I have a vague memory of seeing two different sorts of 8875, both from Eimac. One with copper anode fins, the other with some form of cast alloy. That could account for a weight difference if it appl
/archives//html/Amps/2015-12/msg00020.html (7,248 bytes)

99. Re: [Amps] worthwhile patents on RF amplifiers? (score: 1)
Author: Steve <g8gsq72@gmail.com>
Date: Thu, 18 Feb 2016 15:37:36 +0000
The first patent number didn't bring anything up for me, so I searched for Mr Dishop, who appears to be president of Dishtronix who, I think, own TenTec and Emtron. Several amplifier patents come up,
/archives//html/Amps/2016-02/msg00048.html (9,683 bytes)

100. Re: [Amps] Filament monitoring - LOOKING FOR ELMER (score: 1)
Author: Steve <g8gsq72@gmail.com>
Date: Thu, 7 Apr 2016 17:46:55 +0100
Don't rule out an intermittent in the heater wiring, socket connections or even inside one of the tubes. A bad joint or dodgy connection will show up as low current and cause a trip. Your guess at th
/archives//html/Amps/2016-04/msg00009.html (8,717 bytes)


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