>>>AA6YQ comments below
-----Original Message-----
From: rtty-bounces@contesting.com [mailto:rtty-bounces@contesting.com]On
Behalf Of Kok Chen
Sent: Friday, April 06, 2012 1:31 PM
To: RTTY Reflector
Subject: Re: [RTTY] software question
On Apr 6, 2012, at 10:11 AM, Ed Muns wrote:
> But, if you are tuning the band
> with AFC enabled you will likely be transmitting off-frequency unless you
> disable AFC or enable NET which is a second function in MMTTY that also
> moves your transmit audio tones to match your received tones. This, of
> course, only works with AFSK transmission which is one of the advantages
of
> using AFSK instead of FSK.
Transmit frequency agility is easiest to implement in AFSK. As Ed mentions,
you simply match the transmit tone pair to the receive tone pair.
However, the use of transmit agility is not restricted to AFSK. It can also
work on FSK.
As long as you have CAT capabilities to offset tune the transmitter, you can
implement transmit agility in FSK. Many transceivers have the ability to
apply XIT through CAT. With the transceivers that don't, you can use A/B
VFOs.
With FSK, the VFO offset stays fixed at the 2125/2295 pair, instead, you
change the RF synthesizer by the amount you wish to move. Just send the CAT
command right before you commence transmission.
>>>DXLab's WinWarbler, which incorporates the MMTTY engine, provides an Opt
button that when clicked QSYs your transceiver so that the selected signal's
Mark and Space tones are on 2125/2295; this also aligns the transceiver's RX
RTTY filter with the signal. Depressing the CTRL key while clicking the Opt
button both QSYs the transceiver and disables AFC, preventing subsequent
"excursions".
73,
Dave, AA6YQ
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