[Amps] suppressors

Steve Thompson g8gsq at eltac.co.uk
Thu Jul 12 07:01:34 EDT 2007



c.s. wrote:
>          There has been , in the past, much discussion about parasitic 
> suppressors in this list.!! What I'd like to see is a comparison between 
> the "nichrome" and the " copper" wire suppressors , in actual use by 
> actual people!! I've used both and have not seen much difference between 
> the two.!!!  Currently I'm testing both and haven't found much 
> difference in 10 mtr. performance!!!
You probably won't see much difference on 10m - the suppressor should be 
adding 1-3 ohms in series between the plate and tune C. The circuit 
impedance is typ. 2-4k, so the power loss is a few tenths of a percent.

To me a measure of 'goodness' of a suppressor is the ratio of series 
resistance it adds between the plate and tune-C at 30MHz and 100MHz. 
I've just spent an idle hour making and measuring a number of 
suppressors to give different values of R at 30MHz, using copper and 
nichrome for the inductor part. In every case so far, copper gives 
better 'goodness'.

Steve


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