[Amps] Solid State HF High power linear amps

S. J. Blackwell w5lu at hotmail.com
Mon Mar 28 22:22:36 EST 2005




>
>Yup,
>
>Plus the solid state designs splatter something awful without a filter on 
>the end. Most amateur amps have a switchable filter on the output 
>(switchable between each band)

Not so. The filters are for harmonic control. My 1KW MRF150 amp (2ea 4x150 
amps in PP parallel with combiners beats the socks off all of the standard 
ham xcvrs except some that operate the  outputs class A. This is 
particuliarly true for 5th and higher order IMD.

Most transistors for this frequency range (2-30 MHz) run on 12-18 Vdc and 
just a few higher. The transistors were really designed to be used as a 
single push-pull stage even though they can be split and combined.

Not so . My MRF150's operate at 50 volts.

I agree about the  tube amps can take a hit and keep on ticking. I have kept 
my Alpha 89. (Which also has better IMD expectation than a 4CX800 amps, but 
not much better than the MRF150's higher order IMD. (The ones that really 
mess up the band) The 4CX800' do make the best econonic  sense.


73,
Sam Blackwell, W5LU




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