AVT for RTTY?
20 messages in this thread
Paul,
I recently read your comments about using the AVT with the Overview
option board. I recently purchased my first Receiver and an AVT at
practically the same time, so I am new to both the SWL hobby and the AVT.
Could you give me an idea as to the cost of the Overview board?
Also, do you know if a terminal program exists to allow the AVT to to
decode RTTY and Morse transmissions? I would assume this would be a piece
of cake for the AVT, since it does fax.
Nick
Nick,
The AVT manual contains the Overview Systems phone number. You might
want to give Tim a call for more information on the Overview board. The
board is in the $100-$125 range.
As far as the AVT_Master software is concerned, you may want to talk to
Ben Johnson over on AMIGAVENDOR (Black Belt Systems) since he is the
author. RTTY and Morse transmissions do not fall into the category of video
transmissions. The AVT system is a video system. There are other solutions
available for less money for morse and rtty.
Cheers, Paul (WA1OMM)
er… "Ben Williams". Used to be Ben Blish, but I have never been (yet,
anyway, as Obie-wankenobie once said) Ben Johnson. :^)
Otherwise, right on the money.
BBS->Williams.Ben[AA7AS]
OK, Ben, guess this bell tolls for you… Since, as I understand it, both
fax and RTTY operate using frequency-shift keying, and since AVT does a
super job with fax, could software be written to allow AVT to decode RTTY?
Or am I overlooking something obvious? I am very much in the learning
stage here and would appreciate any light you could shed on the theory
behind AVTs operation.
Nick
No, you're not overlooking anything major. Here are some issues to
consider, though:
Most RTTY demodulators have pretty extensive filtering before the
demodulator. It helps them "see" the RTTY signal regardless of CW and
QRN/QRM near (even very near) the signal.
The AVT has to "see" FSK input from 1000 hz to 2300 hz with no breaks. So,
it's got no filtering. This means that it would be subject to rather severe
noise interference.
Finally, I think we'd have to write a RTTY mode into the demodulator,
because it's doing some really weird things to the incoming audio to hadle
wide-band signals somewhat better. It could probably *do* RTTY now, but it
might screw up at 110 baud ASCII due to the signal munging it does.
Otherwise, sure. :^)
BBS->Williams.Ben[AA7AS]
Thanks for the clarification…guess the AVT isn't real well-suited to act
as a RTTY demodulator after all. Say, since Black Belt Systems is the
number 1 Amiga developer of radio-related products, perhaps there is a
place in your lineup for such a device? An inexpensive RTTY and Morse
decoder built around a FSK demodulator/tone decoder ic? I saw something
like that in a recent issue of Popular Electronics for the peesea. Ok, so
it probably wouldn't be your next HAM-E! I'd buy it.:^)
Nick
We appreciate the input, but somehow, I doubt it. :^) The RTTY demodulators
on the market (PK-232, KAM) (You'll notice I carefully left out the
MFJ-1278, which I consider to be class "A" junk) are extremely high
quality, feature laden, computer-type independant, and very reasonably
priced. We are in the process of producing support software for these, and
I expect we'll stick to that tack for a while.
Sorry about that; but we just don't see the market for an el-cheapo
decoder… and after FCC, it wouldn't be all that cheap anyway.
Best thing to do, if you can, is home brew one.
BBS->Williams.Ben[AA7AS]
Ben,
I'd be very interested in any software you might produce for the AEA
PK-232. Is it safe to assume that you'll announce availability of such a
product here?
Darron, NR0Y
It's safe. :^) In the meantime, get CoComm – it's configurable, and there
are specific configures already available that drive the PK 232. And CoComm
is free to CIS users. See DL6, AmigaVendor.
BBS->Williams.Ben[AA7AS]
Thanks, Ben, I'll check it out.
Darron
Oh, well….just a thought. Guess I'll investigate the units you
mentioned, especially if Black Belt is developing support software for fax
, etc. Do you recommend one unit over the others (PK-232 vs. KAM)?
Nick
I _personally_ like the PK 232 better, it has more support for the
inquisitive SWL/HAM. THe KAM has dual ports. You have to decide which you
want more.
Oh, yeah. :*) The PK-232 has a LOT of neat LEDs on it that tell you what
it's up to. I like that a lot. The KAM is a "box".
BBS->Williams.Ben[AA7AS]
Thanks for your recommendation. Sounds like its the PK 232 for me.
Flashing LEDs are my _life_!
Me too. :^) You know about our "SoftPanel" product? 32 LEDs for the front
panel of your Amiga? You're talking to one of the original
BlinkenFlashenSpitzenSparken kids.
Hi Ben, I wanted to tell you that my James Blish collection is getting
bigger (Old amazings) and that I was confused by the thread. Isint the AVT
the premere FAX machine????
More or less, yeah. You can get more resolution than the stock amiga
hardware offers with it – but it's not 100% supported (yet). You have good
taste in SF authors. :^)
I would be it as well except that I've sunk money into a UTU.
Paul,
Thanks for your reply. I must say you have me intrigued…may I ask
what you are referring to when you mention "other solutions available for
less money for morse and rtty"? Do you mean a hardware/software
combination for the Amiga?
Nick
Well, Kantronics, AEA and others make TNCs (terminal node controllers) that
have CW and RTTY demod capability with appropriate filtering. All you need
to do is connect your Amiga to them as you would with any modem.
Software is your favorite terminal program.
Cheers, Paul (WA1OMM)
Thanks for your reply, Paul. I am investigating the units you mentioned.
Sounds like Black Belt will be doing some support software, which suddenly
makes owning one a much more attractive proposition to me!
Nick