[1000mp] INrad Collins vs Yaesu Collins 500 Hz Filter for 1000MPs

[Ian White, G3SEK]

Earl W Cunningham wrote:
>
>"Has anyone measured or judged any difference in performance between
>these guys?"
>==========
>The INRAD and the Yaesu Collins 500 Hz mechanical filters are 
>identical. I recommend the INRAD 400 Hz crystal filter for the 455 kHz 
>I.F. to avoid the broad skirts of the mechanical filter.
>

The INRAD 400Hz filter makes a dramatic difference to the sub-RX, 
because that one filter is all the skirt selectivity you have.

I found the Collins filter almost useless in the sub-RX because its 
skirts are so broad. The much steeper skirts of the INRAD filter really 
bring the sub-RX to life for CW and RTTY, both as a second RX and for 
spotting in split pileups.

Imagine you're listening to CW at 700Hz in the center of the passband. 
Interfering signals at 200Hz and 1200Hz will be at least 30dB weaker 
through the INRAD filter, and signals further down the skirts are weaker 
still. Data for both filters are on the INRAD website - but the 
important thing is that you can *really* hear it!


-- 
73 from Ian G3SEK