[Scanner] notch filter

[Edmund F Leavitt]

A number of years ago the ARRL ran an article on a very compact
asymmetrical notch filter that is available from a fellow in Florida.  I
bought one and have found it to be excellent at protecting receivers (and
transceivers as well) from pager interference.  At the time I had a 152.8
MHz system roughly a quarter mile from my location.  It beat up
mercilessly on receivers.  The filter I chose provides a very deep notch
that is steeper on one skirt than the other.  I have swept it with
various test equipment and found it to exceed the advertised specs.  

In the years since I bought mine, the vendor has expanded his line of
products, and now has included graphs generated with an HP network
analyzer on his web site for the skeptical. 

 In short, he offers sharp filters, with very low insertion loss, in a
ultra compact package.  I recommend them highly.   I specifically asked
for one where the tuning screws were not cemented in place so I can
retune them to fit the situation.   If you do not have adequate test
equipment to properly retune such devices, get the standard product that
is 'factory tuned' and cemented to prevent accidental misalignment.


http://www.parelectronics.com

On Sun, 12 Jan 2003 13:28:01 -0600 Scott Millick <smillick@wamusa.com>
writes:
> I have a nearby paging freq that is a problem when it overloads my 
> scanners 
> on VHF. Is there anywhere that a notch filter for one freq can be 
> purchased?
> 
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> 


****************************************************************
Edmund Leavitt                   Ph:    253 582-5034 
Ham/MARS/SHARES:       KA7UKN / AFA5AH / KPS654 
Lakewood, WA                   N 47: 09'   W122: 31'