Not my experience. 2Tone handles QRM better than the group delay from a
narrow filter.73,Ed W0YK
-------- Original message --------From: john@kk9a.com Date: 2/17/21 17:37
(GMT-08:00) To: cq-contest@contesting.com Subject: Re: [CQ-Contest] RTTY
contesting; filters I am sure that is true on a quiet band. I wish that I could
find a 600hzopening anywhere on 20m in last weekend's contest. Any QRM in my
passbandmakes decoding very difficult. John KK9A Ed Muns w0yk wrote:An IF
bandwidth of 600 Hz is ideal with our modern software decoders.(Narrower
bandwidth introduces phase shift that degrades copy error rate.)Older radios
often don't allow narrow filtering in SSB mode. Yes, you wantto shift such
that the bandpass is centered on whatever tone pair you use. I do like lower
tones and typically use 915/1085 which is less fatiguingover long periods.
OTOH, their TX audio harmonic is still within the normal2 kHz bandwidth for SSB
transmitters when transmitting AFSK. Not a problemfor those of us using FSK.
73,Ed W0YK_______________________________________________CQ-Contest mailing
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