On Wed, 12 Nov 2003 06:29:48 -0600, "Keith"
wrote:

As I understand it, the secondary DSC receive antenna hookup on the 802 is
optional. I don't have one hooked up, but I was wondering what everyone
thought about the utility of this. Is it really optional?

No, it's not optional. I asked Icom where we were supposed to put
another antenna on a small sailing vessel. The stupid thing needs a
TR relay!

What is the
benefit of having a second receive only antenna? What won't work if I don't
hook one up. I just cringe at having to put yet ANOTHER antenna up there!

DSC scanning (the DSC button that scans all the DSC HF freqs) won't
work without it.

I don't have another antenna on Lionheart for it. I'm using the open
end of a shroud that's not grounded at the chainplate in fiberglass,
sort of shunt-fed the mainmast. After hooking it to the shroud, I
plugged it into the regular receiver jack on the Icom to see how well
it receives. Seems to be a good receiving antenna, so I'm using that
for DSC receive.

I think the thinking of a separate antenna is because of the tuner.
If you have the main antenna jack through the tuner on, say, 8 Mhz,
it's a lousy receive antenna on 12 or 4 or any other band. So, they
provided a separate jack for DSC receive. I don't like it, but it
sounds logical. I did get one distress call on it when I left it
scanning all night. Its DSC lat/long was off the coast of France, so
I guess the shroud works fine....(c;

Disconnect the shroud and measure the resistance between the boat's
ground and the chainplate you took it off of. Ours is open, no
connection. The mast is grounded, so hooking DSC to this chainplate
effectively makes a loop antenna from the chainplate, up the shroud,
down the mast and back to the radio through the ground system. At the
feed point where you hook the CENTER CONDUCTOR to the chainplate, do
NOT connect the shield to anything, just seal it off and leave it
open. All the shield does in my hookup is shield the receiver from
the NMEA broadband data interference back at the nav station by hiding
the antenna wire from it inside the coax. It's called a Faraday
Shield. Seems to work great aboard Lionheart, but your mileage may
vary. There aren't many stations using DSC for calling, it seems.
They're probably on Marisat...(c;



Larry W4CSC

"Very funny, Scotty! Now, BEAM ME MY CLOTHES! KIRK OUT!"