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Re: [CQ-Contest] RTTY contesting; filters

To: john@kk9a.com
Subject: Re: [CQ-Contest] RTTY contesting; filters
From: WW3S <ww3s@zoominternet.net>
Date: Wed, 17 Feb 2021 20:56:13 -0500
List-post: <mailto:cq-contest@contesting.com>
I was cranked down to 200 hz and would have gone tighter if I could.....btw, 
congrats John on what appears to be a first place finish, I just couldn’t get 
much going with low power this weekend....

Sent from my iPad

> On Feb 17, 2021, at 8:37 PM, john@kk9a.com wrote:
> 
> 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
> 
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