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

Re: HRD and two radios: was dual IC-706 station

Quoting Wayne Estes <w9ae@charter.net>:

> Bruce Robertson wrote:
> Is anyone aware of another program that does linear tracking with two 
> radios?
> Wayne replies:
> SatPC32.  One program graphically tracks satellites and tunes two 
> radios.  I'm not sure if Ham Radio Deluxe does this, but SatPC32 polls 
> the CAT interface of the radio that you tune, to automatically track the
> VFO of the second radio.  Functionally, it turns two radios into a 
> "satellite transceiver".

Thanks for this. For some reason, I wasn't able to find this function in
the Demo version. I shall look harder.

However, I also intend to persist in using Ham Radio Deluxe and help
testing this feature. I think HRD is a very important program for Amsat
members to nurture. As the "Swiss army chainsaw" of CAT, it puts satellite
operation on the desktop of every user who downloads it. So many hams have
2m and 70cm built into their radios that they're just a click away from
hearing AO-51 for the first time.

> George Abbott wrote:
> I was told that they [IC-706] lack the necessary sensitivity for SSB 
> signal detection in the vhf and uhf bandwidths.
> Wayne replies:
> ALL ham transceivers lack sensitivity in the VHF and UHF bands.  That's
> why we use low noise preamplifiers at the antenna when we need to 
> receive weak signals such as satellites.

In case George was referring to the FT-817s, I'll add here that with runs
of cable that produce less than .5 dB loss and a 4 element 144 yagi, a
FT-817 hears VO-52 reasonably well without a preamp.  Similarly, I *can*
hear FO-29 without a preamp using my 8-ele 435 yagi and a < .5 dB run of
cable, but the preamp adds quite a bit. In my case, because of the low
cable losses, both preamps are in the shack. 

One counter-intuitive result of the noise figure math is that it really
doesn't matter how crummy the radio's specs are if you're using
mast-mounted preamps. 

However, even if one can hear signals without preamps, there's another
great reason to have them: ferreting out QRM. Without the preamp on 144, I
found that VO-52 was hit-and-miss. Some passes I'd hear, others I wouldn't.
It turned out my CRT computer monitor was a major hash generator, and when
it was in sleep mode it would go silent. By raising the noise floor to just
below S1, a preamp makes local QRM like this visible. If I have S5 noise
from my darn ethernet router, I know VO-52 will not be coming through.

73, VE9QRP

Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org