[1000mp] Question to those using the INRAD Roofing filter

William Diamond wjdiamond at sbcglobal.net
Thu Aug 19 22:07:13 EDT 2004


Thanks for the info folks...

           WILLIAM J. DIAMOND
          ROGERS, ARKANSAS USA

        HAM RADIO OPERATOR WRØT
 VISIT MY NEW RADIO ROOM REVISED 7-04, AT
           www.wjdiamond.com

       DIGITAL PHOTOGRAPHY SITE IS AT
http://pages.sbcglobal.net/wjdiamond/index.html


-----Original Message-----
From: 1000mp-bounces at mailman.qth.net
[mailto:1000mp-bounces at mailman.qth.net]On Behalf Of Thomas Beltran
Sent: Thursday, August 19, 2004 8:47 PM
To: All about Yaesu 1000mp
Subject: Re: [1000mp] Question to those using the INRAD Roofing filter





> Could someone please tell me what a "roofing" filter is ??   I am not
> familiar with that term.
>
It is essentially the First IF filter, setting the maximum bandwidth for the
radio.  In the Mark V, like George's (and mine) with the Inrad Front-End
mod, the Roofing filter mod replaces that front-end mod.  The mod goes after
the stock, 12 khz. 4 pole crystal filter.  It is a 4 khz., 6 pole crystal
filter, with a small amp that more than compensates for insertion loss.
Since it sets the maximum bandwidth, one must use the sub-receiver to listen
to FM.

About all I can say about the filter is that my radio sounds much "cleaner."
And, when other hams in the area are on the air (usually 17 meters), I have
to tune within a few khz. before I get the de-sensing - prior to the mod, I
would get the de-sensing within 15 - 18 khz., so that is quite an
improvement.  In other words, I actually have to hunt a bit :)  I live in
the San Fernando Valley (NE of downtown Los Angeles), and I have quite a few
neighors who run the legal limit.  I almost never use the noise blanker, but
recently, the occasion arose, and it seemed to work very effectively.  Tom
W6EIJ




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