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[Amps] Amplifier for 630 meter band

To: <amps@contesting.com>
Subject: [Amps] Amplifier for 630 meter band
From: "Jim Thomson" <jim.thom@telus.net>
Date: Fri, 10 Nov 2017 12:50:26 -0800
List-post: <mailto:amps@contesting.com>
Date: Fri, 10 Nov 2017 08:01:03 -1000
From: Merv Schweigert <k9fd@flex.com>
To: amps@contesting.com
Subject: Re: [Amps] Amplifier for 630 meter band

<Lot of work for naught..   the power limit on 630M is 5 watts and even 
with a very poor antenna
you only need 100 to 200 watts to get 5 out of the antenna.   A single 
or two MOSFET amplifier
will do that no problem and will fit in a mini-box.

NO3M has converted a SB-1000 think it was,  he used it under his 
experimental license which has
higher power limits.   Google NO3M and there are pictures or some info.
There are a couple others on line that converted tube amps. Almost none 
use them now.
MOSFET amps are doing 80 to 90 percent efficiency,  why waste a tube amp 
at 50 to 60
percent.
No high voltage,  no fans,  much better ways to go these days, 
especially on 630M

73 Merv K9FD/KH6


##  what config are they using to achieve 80 to 90 % eff ??   Is it class D or 
E or similar ? 

##  68-70%  eff  on 40m is easy, in class AB on any GG triode...ditto with 80 + 
160m..
And thats in  SSB linear mode.  Increase the bias V a bit, till idle current is 
down to just 10-25 ma,
and eff will go up even more... like typ 74-80 % eff. 

##   You can NOT  run a GG triode at zero idle current in class B,  or  with
more bias V,  still zero idle current, but now class C, or u will get key clix 
on CW.  

##  if u only run  5 watts  ERP, nobody is gonna hear you at the best of times. 
 You cant
work em, if they cant hear you. 

Jim   VE7RF


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