[AMPS] LP Filter Performance

[km1h@juno.com]

On Tue, 30 Mar 1999 13:38:39 +0100 Peter Chadwick
<Peter_Chadwick@mitel.com> writes:
>
>steve says:
>
>	>I've not modelled it, but I think the load on the output side 
>of a
>	>harmonic filter will have insignificant effect (a few dB in 
>typ.
>30+) on
>	>harmonic attenuation with most filter topologies.
>
>
>Depends on the filter and the actual load impedance at the frequency 
>in
>question. You can lose as much as 20dB of attenuation - although the
>likelihood of that much is probably on a par with winning the lottery  
>-
>unless it just happens to be a situation where Murphy works overtime.

I believe it was John Belrose who wrote in QST Technical Correspondence
several years ago. He measured and reported that the topology as used in
ham LP filters had a minimal effect on performance at to at least a 2:1
VSWR. 

I would be concerned with high VSWR on 10/15M.

I'll bring in a ICE filter to work and play on the network analyzer with
various resistive loads.

73  Carl  KM1H

>
>Peter G3RZP
>
>
>
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