[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Alinco HT was MIR?

At 11:22 AM 9/5/99 -0400, you wrote:
>  if you can find the descriminator output of the handy's
>demodulator, then you can receive the 9600 baud Pacsats.
>I just added a small connector to my $88 Alinco UHF HT to bring out the
>discriminator and it lookos like it willl make a great little portable
>9600 baud PACSAT handheld (with the corner reflector).

I'll be very interested to see how this works out.  There are two reasons 
that most FM radios won't do 9600 baud satellite receive.  One, of course, 
is the need to tap the discriminator.  The other is that the IF filters are 
not wide enough.  I remember when the major manufacturers were first coming 
out with dual band FM units that claimed to be able to do 9600 out of the 
box.  I walked around Dayton one year looking at the specs on all of these 
and found that the IF filtering was often less than 12 kHz.  The IC 207H, 
for example, advertises the -6 dB points are at 12 kHz.  The Yaesu FT-90 is 
the same.  Back then, some of these radios had filters that were even narrower.

I remember when I started working digital satellites with an FT 736, 
everyone was swapping out the standard IF filter (I think it was 15 kHz) 
with 20 or 30 kHz filters.  Partly that was because one of the digital 
satellites (I think it was UO-22) had some frequency stability problems, 
but I think the problems may have existed with other birds as well.  I am 
not familiar with anyone who successfully got any of these "9600 baud 
ready" radios to work on the 9600 baud satellites without modification, 
though if I'm wrong I'd sure love to hear about it.

So, I guess what I'm saying is that I think that an awful lot of people 
(including me!) would be extremely interested to hear of the results of 
your experiments with the Alinco.  Please post the outcome regardless of 
whether it works or not.

73, John W2FS

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org