[RTTY] Well darn...

[David G3YYD]

I would like to make a correction FSK or AFSK is not the best performing
transmitting method. The reason is simple all the good decoders use narrow
filters on both tones and then decode the RTTY signal as two differentially
keyed tones separated by 170Hz. They use AM detection not FM detection
techniques.

Therefore FSK/AFSK spectrum is not the best match for the filtering nor for
the decoding. It is not dissimilar to transmitting narrow band voice FM and
receiving it on an AM receiver. The best transmission is to use a matching
signal which is provided by 2Tone DOOK and by FLdigi RTTY. As an added
benefit the signal is very much narrower too unlike some rigs which transmit
very wide key clicks.

Also once set up as John GW4SKA says once set up audio is the way to go.

73 David G3YYD

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of John Barber
Sent: 13 October 2016 18:51
To: 'Don AA5AU'; 'RTTY Reflector'
Subject: Re: [RTTY] Well darn...

The ALC is the most important but really once set and left alone it's not a
big deal. I use AFSK because it saves messing about changing stuff when I
use other modes that need an audio input.
The spot offset can be set up in N1MM to compensate automatically, giving
accurate frequencies in and out. Each to their own .. let's not start the
whole FSK/AFSK thing going again as FSK IS technically better for RTTY but
either work fine for most folk.
John GW4SKA

-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of Don AA5AU
Sent: 13 October 2016 19:28
To: RTTY Reflector <rtty at contesting.com>
Subject: Re: [RTTY] Well darn...

Thom wrote:
"Besides what is so bad about running AFSK for all this contesting?"
1. Have to keep an eye on your ALC at all times to make sure you don't over
modulate.2. On some radios, you can't use special CW/FSK filters on
receive.3. On some radios, you can't use Twin Peak Filters (TPF).4. Will
have to tune 2.1 kHz from nearly all packet spots to find the station
spotted.5. Spots you send to the Packetcluster will be off by 2.1 kHz for
most everyone else.
That's about it I think.
What is the advantage of FSK?
1. You don't have to worry about 1-5 above.
73, Don AA5AU

 
      From: Thom <ki8w at ki8w.com>
 To: rtty at contesting.com
 Sent: Thursday, October 13, 2016 1:17 PM
 Subject: [RTTY] Well darn...
   
After 3 days of building and re-building a FSK interface between my USB
laptop and my Kenwood TS-480 and not getting Windows 10 to recognize my USB
to Serial adapters, I have given up.

Besides what is so bad about running AFSK for all this contesting?


I would like to know.

73


Thom KI8W




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