----- Original Message -----
From: Riley Williams <[EMAIL PROTECTED]>
Subject: Re: Any Plans For Data Radio's?
> Hi David.
>
> > Sorry if this is slightly off topic? I am new to the list
> > but have been a linux fan and ham for a long time. I have
> > seen several emails on the list about plans for TNC's /
> > packet modems, etc.
>
> > Does anyone know of any plans for data only radios (xcvrs)?
>
> Depends what you mean by "data only radios"...
>
> If you mean "radios that can't be used for anything other than
> data" then there's no such thing - any radio can be converted to
> work with data, and likewise can be converted to work with voice
> as well.
Aren't you being a bit perdantic Riley. But then again, from listening to
you via VHF repeaters in the UK, that wouldn't be you otherwise! ;-)
The guy means data radios. IE: Transceivers that have been designed
specifically for the transmission of digital data. As radio amateurs we have
a hands on ability to butcher wireless equipment to do virtually anything we
want, providing the basic design will allow us. Take a design that uses no
voice demod chip, ie: MC3356 instead of a MC3357 (or is it the other way
around).
One has af out, the other has raw data out. The pinouts are similar, but not
the same. Yes you could mod a rig based around the data chip to do voice,
easy on TX, lots of work, if not really worth it, for the RX.
In Europe Motorola used to market a box called the MC-Micro. A synthesized
rig that came in two basic variants - voice and data. The data version could
pass up to 16Kbit/sec with 12.5KHz filters fitted. It was/is a very good
basis for a 9K6 RUH compatible transceiver. A few of them have filtered out
of the commecial world into hands of radio hams, but not many. (I keep
looking!).
> If you mean "radios that can be used for packet radio at 300 or
> 1200 Baud" then just about any radio can be used for that without
> modification.
That's not data, that's damn near semaphore man!
> If you mean "radios that can be used for packet radio at 9600
> Baud or above", then yes, most existing radios require some
> modifications to be made before they can be used for this
> purpose. However, there is a radio on the market that is (or at
> least was) specifically designed for use with 9600 Baud packet on
> the 70cm band, and it was made by one of the major manufacturers
> of ham radio trannies. I don't have the details to hand though.
And 9600baud is old-hat too.
I think that David wants plans for the type of radio that can be used for
38K4 and up. Your basic amateur, indeed commercial spec land mobile voice
radio needs a lot of IF work if you are going beyond 50KHz bandwidths. There
are many designs available, for 70, 23, and 13cm. If you find the homepage
of the Slovenian national radio society, you will find links to their data
experts. They have designs for complete systems that handle 1.222MBit/sec on
13cm, as well as designs for 70 & 23cm.
Then there's the Derbyshire IP Group's web page that details 70 & 23cm data
transceivers suitable for up to 128Kbit transmission.
Check out BayCom's homepage for more designs. Their latest parallel port
based modem works at up to 600Kbit/sec.
If you look closely, you will find many designs from all over the world.
Try these : http://lois.kud-fp.si/hamradio
and http://www.dutch.nl/bdj/index.htm
There. That's better.
Regards
Rob G1ZPU / GB7ZPU
