I attended Contest University at Dayton last year and the RTTY expert
suggested he found that too narrow a filter compromised the decoding.
It seemed to work best when the filter was a little wider. He suggested
500Hz and 250Hz only in the presence of strong QRM. He did NOT like the
dual-tone filtering in the K3 or Icom's twin-peak filter.
It is on slide 3 of the Advanced RTTY Contesting presentation available
in the Files section on the Contest University website.
Buck
k4ia
K3# 101 KX3 #715
On 2/16/2015 12:47 PM, [email protected] wrote:
David Moes
VE3DVY
Since I find that the 8 pole 250 Hz filter is really a bit wider I
tell my K3 in filter setups its 300hz It works fine for me this way
including on RTTY
During the WPXRTTY this weekend I had good luck copying weak signals
right beside a power house signal using the 250hz filter.
--- Original message ---
Subject: Re: [Elecraft] K3: best roofing filter on RTTY
From: Jim's Desktop <[email protected]>
To: <[email protected]>
Date: Monday, 16/02/2015 9:49 AM
The narrowest filter I have in both receivers is the 400 Hz one. I
borrowed a K3 that had a 250 Hz filter in it once and tried it on RTTY.
It works, but it's right on the margin of being too narrow. If someone
is using one of the older Packet TNC's that have RTTY mode in them (they
used 200 Hz shift instead of 170 and there are still a lot of them out
there) it's really hard to get them tuned in with a 250 Hz filter,
especially in weak signal/selective QSB situations. The 400 Hz filter
doesn't seem to have that limitation though it does let slightly more
noise in (easily handled with the DSP filters anyway.
Jim - W0EB
On 2/15/2015 11:35 PM, David Cole wrote:
Hi,
I ordered and use the 400 for RTTY, I suspect the 250 is a bit to
narrow.
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