John Bradley wrote:
>
>
> AFSK sends diddles , as in MIXW. Nice sounding? well..
>
> JOhn
> VE5MU
Any serious "routine" (see it as a program or a combination of lever
movements) generates "didles" whenever there is no message to be
transmitted.
"Cheapo" computer programs omi
That pesky FSK RTTY
Thanks Danny and Rick. So, before sound cards, I used an old fashioned TNC
and a rig that would only do AFSK not FSK. How did that work ? One thing I
did not like about the TNC days was that when sending RTTY it did not generate
any of that nice sounding RTTY diddles.
AFSK sends diddles , as in MIXW. Nice sounding? well..
JOhn
VE5MU
- Original Message -
From: Andrew O'Brien
To: digitalradio@yahoogroups.com
Sent: Sunday, February 25, 2007 10:19 AM
Subject: Re: [digitalradio] That pesky FSK RTTY
Thanks Danny and
Thanks Danny and Rick. So, before sound cards, I used an old fashioned
TNC and a rig that would only do AFSK not FSK. How did that work ? One
thing I did not like about the TNC days was that when sending RTTY it did
not generate any of that nice sounding RTTY diddles. Will that now be the
Originally RTTY was strictly FSK. The frequency was actually shifted +/-
170 Hertz. This was by either shifting the VFO or switching between two
crystals. At the far end a discriminator recovered the FSK modulation.
When RTTY operation shifted to computers or more modern terminal
devices, an
In the "old days" the VFO was shifted by mechanically switching a
smaller capacitor in and out across the VFO tuning capacitor. This is
probably why mark high was the standard, since adding capacitance would
pull the frequency lower for the space tone.
Today we are mostly using synthesized VFO'
OK, I think I get it but..
> With FSK, there is no setting up of the drive levels from the sound card
> since you are basically switching the frequencies from inside the rig.
>
tell me more about the above. How does the switching of frequencies
generate tones heard at the other end.
Andy,
The main advantage with FSK is that you have the ability (with some
rigs) to use certain filtering specific to RTTY. My ICOM rig has
superior filters that are double humped and shaped for the 170 tones. I
can not use them on AFSK, but due to the requirement of needing another
COM port an
OK, my cable for my Microkeyer should arrive in a day or so My new
rig provides for FSK RTTY as opposed to the AFSK my old rig has been
providing for the past 18 years. I have seen many post over the past
few years about FSK, but have paid little attention. It seems though
that many have some
