[Amps] Â GS23B Plate load resistance for HF

[Carl]

That might fly in a low activity area but here in the packed NE the crud 
generators are very noticable and annoying. Thats one reason I do most of my 
6M DXing on CW and the other is I cant stand listening to most of the ex and 
likely still current CB no coders on SSB.
If I actually want to have an intelligent "talk" to someone it is around 
50.2 and up on SSB and 50.4 on AM.

Being on top of the highest hill in 20 miles + just aggravates the 
situation. With a very low band noise it doesnt take much crud to cover up 
weak stations.

Carl
KM1H


----- Original Message ----- 
From: "Jim Thomson" <jim.thom at telus.net>
To: <g8on at fsmail.net>; <amps at contesting.com>
Sent: Friday, November 01, 2013 4:24 AM
Subject: Re: [Amps] Â GS23B Plate load resistance for HF


> ## Dunno what the imd was on the 2 holer, 6m amp.  So far nobody has 
> complained.
>
> Jim   VE7RF
>
> -----Original Message----- 
> From: peter chadwick
> Sent: Friday, November 01, 2013 1:16 AM
> To: Jim Thomson ; amps at contesting.com
> Subject: RE: [Amps] GS23B Plate load resistance for HF
>
> Jim,
>
> GS23B tetrode, not a GS35B triode.
>
> What was the IMD on the 2 times GS35B amp?
>
> 73
>
> Peter G3RZP
>
>
> ========================================
> Message Received: Nov 01 2013, 05:31 AM
> From: "Jim Thomson" <jim.thom at telus.net>
> To: amps at contesting.com
> Cc:
> Subject: [Amps]  GS23B Plate load resistance for HF
>
> Date: Thu, 31 Oct 2013 18:54:18 +0100
> From: peter chadwick <g8on at fsmail.net>
> To: TexasRF at aol.com, keepwalking188 at yahoo.com, dezrat1242 at yahoo.com,
> amps at contesting.com
> Subject: Re: [Amps] GS23B Plate load resistance for HF
>
> Assuming 3kV on the plate, 500 volts on the screen and AB1 operation in 
> grounded cathode, I calculate a PEP output of 1540 watts, a dissipation of 
> 1240 watts, efficiency 55% and a load resistance of 1570 ohms - 
> calculation method as per RCA.
> Peak plate voltage when loaded is 3700 volts.
>
> The 4CX1000A has a much bigger allowable plate swing  before the plate 
> current curve starts to bend - which helps the efficiency.
>
>
> 73
>
> Peter G3RZP
>
> ##  are u folks talking about a GS23B..... OR  a GS35B ???      On a 
> buddys 2 x GS35B  6M amp,  we managed to get 5 kw out on 50.125 mhz  with 
> 225 watts of drive  from a FT-2000.
> He could easily bury the slug past 5 kw.   At which point the  10 kw slug 
> was inserted.  The FT-2000 is capable of 250w out on 6m.      Plate V  was 
> aprx  4300 NO load on RX...... and   4150 vdc under load.
> The 150 vdc drop consisted of a 100 vdc drop  from drawing 2A  of plate 
> current  through the 50 ohm glitch Resistor.... + another  50 vdc  drop 
> from the B+  supply.  I had him temp short out the glitch R..to see what 
> the
> real V drop was..... and it was only 50V.    But this was an oddball case 
> where  a 253 lb dahl xfmr was used on one of its lower taps... + a  165 uf 
> filter cap..and 2 ga wire back to the main 200A
> panel.   4150 x 2A = 8.3 kw    5000 /8300 =  60.24 % eff.
>
> ##  carl is correct though.... the  GS35B is like a 4-1000.   Gain goes 
> WAY up when you crank the B+ up.    On my old 4-1000 amps... I would get 
> 600 w out with 2.5 kv under load + 120 w of drive.
> With 4.4 kv under load, and same 120 w of drive.... power increased to 
> 1980 watts out.    Roller coil was optimized in each case to factor in the 
> different plate load Z....and in both cases was tweaked
> for a Q of 8-10  to maximize eff.
>
> ##  4100-4300  under load on a GS35B  is  about the max you can use on a 
> good tube.   Much above that..and you get into trouble.
>
> Jim  VE7RF
>
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