[GreenKeys] rtty 101

[Roy Norris]

Hi Gil,

I'm a Ham radio operator, K4EEG and have operated RTTY for many years.  I 
will try and answer your questions.

1.  Regarding RTTY demodulators:

For many years, Hams and others wishing to copy radio Teletype would use a 
hardware demodulator or "terminal unit aka TU"  .  But with the advent of 
digital signal processing and personal computers, many today use a computer 
program that accomplishes all of the TU functions and more as long as the 
computer is equiped with one of the "Sound Blaster" style audio 
cards.  These programs approach  and in many cases surpass the best of the 
hardware TUs.  Additionally, they also perform the function of decoding and 
presenting the decoded message on your computer screen.

There are a wide variety of programs, some of the best costing $0 up to 
many thousands of dollars depending on what you want to do. The more 
expensive programs copy not only radio teletype (RTTY) but many other 
digital modes such as Pactor, Sitor (ship based messaging and weather), and 
a wide variety of government/military digital modes.

The down side of the software approach is that most of them are not 
designed to run a mechanical machine and output to your computer monitor.

If you want to run a regular Teletype machine on a local loop, you will 
probably need a hardware TU.  The best of these is the HAL ST-8000 in my 
opinion but others favor the Dovetron units (I have both).  The HAL units 
go on ebay for around $400 to $450.  Dovetron units can be picked up on 
ebay for $150 or so and there was a move afoot here on GreenKeys to do a 
group buy of some surplus units at considerably less than that.

Other good hardware TU's include the HAL ST-6000, HAL ST-5000, and the HAL 
ST-5.  These turn up from time to time on Ebay and some of the Ham swap boards.

Currently one of the most popular RTTY programs that does it all for you is 
MMTTY available free at :  http://www.aa5au.com/rtty.html  .  This is also 
an excellent page on getting on RTTY in general.  I don't believe MMTTY 
will run a mechanical machine, however.

There are several Dovetron units currently available on Ebay now : 
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3007323114&category=1502

                                                                 http://cgi. 
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3007165589&category=4671


2.  Receivers:  Once again, a wide choice is available.  To have maximum 
flexibility and copy the most signals, a general coverage shortwave 
receiver would be the most desireable.  Ham receivers are sometimes 
"general coverage" but are often not.  Of course you can copy RTTY on the 
Ham bands with them.

A good site on receivers is 
:  http://members.fortunecity.com/swradios/  and 
http://www.rffun.com/index.htm  and http://www.dxing.com/swrx.htm


3.  Antennas:  Almost anything will work.  The longer and the higher the 
better.  But I have used very successful antennas mounted in my attic or 
disguised as a flag pole in the back yard.  There are some very fine 
"active antennas" available now that require very little space.

A good site that will make you an expert is:  http://www.dxing.com/swrx.htm

Let me know if I can help in any way.  You can reach me via email 
(rnorris@charter.net) or telephone 205 972-0707.

Good luck -- Roy, K4EEG




At 10:38 AM 2/13/2003 -0700, you wrote:
>Hi folks:
>
>You may recall that I know diddly about the radio side of things here, not
>being in amateur radio.  Well, on a technical level I know radio to a
>certain degree, but certainly not at a practical level for rtty work.