[GreenKeys] newbe asking about HAL ST800a's on ebay

[Roy Morgan]

On Jan 2, 2009, at 4:29 PM, <eugene at hertzmail.com>  
<eugene at hertzmail.com> wrote:

>
> Thanks, John. Does seem to be a little limiting without a  
> demodulator in
> it. Drift isn't very attractive either, hi hi
> I do see there is a spare socket for a crystal for another center
> frequency. Wonder if that could be useful.

I have a TIS-3, but it's missing a lot of parts, and has never run  
here.  If I remember the information I have on it:

- the crystals needed to create a different center frequency are low  
frequency units.  on the order of 200 kc.  Those might be hard to  
find, or hard to pay for.  But there are ways around that problem.
- There are four selectable center frequencies in the thing as it is:  
1900, 2000 and 2250 cps, and a "spare" you enable with that expensive  
crystal

> Did TMC make a demodulator to match?

TMC did make two demodulators as I understand it, the CFA-1(tubes) and  
CFA-2 (early transistors).  But I wouldn't say they were meant to  
"match" the TIS.  Many military comm centers were divided into two  
parts: transmit and receive, separated perhaps by tens of miles.  So  
the transmit functions may have had very little receive activity at  
that site.

In any case, I'd like to find a CFA.  The tube one is preferred,  
'cause I can fix it. The transistor one would be ok, too.  I would  
expect the TMC demodulators to perform only moderately well,  
especially when compared to the Dovetron, for instance.  I want one to  
complete an all-TMC RTTY station I have planned.  'Got all the rest of  
what I need.

Roy


Roy Morgan
k1lky at earthlink.net
529 Cobb St.
Groton NY, 13073