Re: [RTTY] Question

["David G3YYD" <g3yyd@btinternet.com>]

Fred

If you want to know more about RTTY then have a look at Chen W7AY web site
and in particular this bit of his website
http://www.w7ay.net/site/Technical/RTTY%20Transmit%20Filters/index.html

Also Andy Flowers K0SM has a very good article on actual TX bandwidths at
his web site:
http://www.frontiernet.net/~aflowers/k3rtty/k3rtty.html

The first thing to know is FSK on most radios have no filtering and as you
will see form Andy's web site have very wide signals. The exception to this
is the Elecraft K3. The second thing is that correctly adjusted AFSK when
used with a good radio has a narrow TX bandwidth without compromise to
received performance. If you use MMTTY then the default setting are not good
use TX band pass filter on and 512 taps.

Many rigs which have too large a AFSK input signal will produce 2nd harmonic
output that will cause QRM to other amateurs. This is totally avoidable by
attenuating the sound card output by about 20dB, a 10K series resistor and a
1K resistor to ground will do this for you. Also make sure that the tone
frequency is above 1500Hz so the SSB filter in the radio will attenuate any
harmonic distortion to levels that are unlikely to cause QRM to others.

73 David G3YYD

-----Original Message-----
From: RTTY [mailto:rtty-bounces@contesting.com] On Behalf Of Fred Souto
Maior
Sent: 17 May 2014 20:23
To: rtty@contesting.com
Subject: Re: [RTTY] Question

Can someone pse tell me how many kcs are used by a RTTY signal ??
This is relative to people operating split and receiving up 1 Khz.
Usually the TX frequency of the DX station is QRMed by the callers just 1
and some times less then 1 up. And if we have a local stn calling it's
impossible to get a decent signal from the DX. Why not put the RX frequency
2 or 3 up ??

Fred - PY7ZZ



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