[CQ-Contest] RTTY contesting; filters

[john at kk9a.com]

I am sure that is true on a quiet band. I wish that I could find a 600hz
opening anywhere on 20m in last weekend's contest. Any QRM in my passband
makes 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 want
to 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 fatiguing
over long periods.  OTOH, their TX audio harmonic is still within the normal
2 kHz bandwidth for SSB transmitters when transmitting AFSK.  Not a problem
for those of us using FSK.

 

73,

Ed W0YK