[RTTY] Inrad filters for rtty question

[David Hachadorian]

----- Original Message ----- 
From: "David Ashworth" <fathom at Access4Less.net>
To: <RTTY at contesting.com>
Sent: Monday, March 22, 2004 10:39 PM
Subject: [RTTY] Inrad filters for rtty question


> Enjoyed the last contest and have a question for any
operators that may be
> using a Kenwood TS850.  I seem to have one Kenwood
filter in my radio
> (YK-88SN1).  There are two more empty slots for
filters, one is for the 455
> KHz IF and the other for the 8.83 MHz IF.  As the
contest got going, I used
> the slope tune control to neck down the signals, but
perhaps another filter
> would also help.  I see that Inrad makes several
filters-a 250 for 455 and
> 8.83 and a 400 for 8.83.  Wonder which filter(s)
would be a good choice to
> reduce the adjacent stations but not get too narrow?
Thank you for your
> help, Dave, NC6P.

I use a pair of Kenwood 500's in my 850's
and have never found a need for anything
narrower, either on cw or rtty.

I am always amazed that, on both of those modes,
people routinely call at up to 70 Hz off
frequency. Sometimes, they are even further
off.

With a 500 Hz filter, and 170 Hz shift, a caller
can be up to 165 Hz off freq and you will still
hear both the mark and space tones, so you immediately
know which way to roll the rit.

With a 250 Hz filter and 170 Hz shift, a caller has
to be within 40 Hz for you to hear both tones. Are
you hearing the mark or space? Where IS this guy,
up or down?

I used to have a TS-830 with a pair of Inrad 400's,
and I definitely wouldn't want anything narrower
for cw. That combo was right on the borderline for cw.

I think 500's give you more situational awareness
of what's going on beside you. I don't want to set
up and start cq'ing within 125 Hz of a loud station's
mark or space, which you could do with a 250. I like
to hear what's on both sides. If I am having trouble
copying with a 500 Hz filter, then maybe people are
having trouble copying me, too.

Dave Hachadorian, K6LL
Yuma, AZ























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