[AMPS] Zener screen supplies

[Peter Chadwick]

Incidentally, whatever the advantages or disadvantages of using zener diodes to
regulate the screen, if you are going to drive an amp from a TS2000, it wouldn't
appear to matter what you do from the linearity viewpoint. 

The latest Radio Communications has a review of the TS2000: 

3rd order products at the 100 watt level at HF are at best -28dB relative to
tone (-22dB rel PEP) with 5th order best at -50dB relative to tone 
(-44dB rel PEP). 

Worst case figures at HF are  -26dB rel tone (-20dB rel PEP) for 3rd order and
-36dB rel tone (-30dB rel PEP) for 5th order.

On 50 MHz, it's a stunning -21dB rel tone for 3rd, and -31 rel tone for 5th.

On 70cm at 52 watts PEP out, it's -22 dB rel tone on 3rd, and -36dB rel tone on
5th.

Receiver performance isn't that impressive, either.

We've been saying here for some time that IMD performance of transmitters is
better than the amplifiers. Maybe that statement now needs a caveat..........


73

Peter G3RZP




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