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? 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 reception won't work without the second antenna for the DSC receiver. But
since it is receive only, it can be any sort of simple antenna, like a CB whip.
I actually use a HamStick, since it can be used as a single band transmit
antenna in an emergency. Works fine on the stern rail since HF is not Line of
Sight limited.
"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? 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!

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!"

How many calls have you intercepted? I've only heard one, that
distress call off the French coast. Those frequencies are sure dead.

On Wed, 12 Nov 2003 05:26:21 -0800, sded wrote:

DSC reception won't work without the second antenna for the DSC receiver. But
since it is receive only, it can be any sort of simple antenna, like a CB whip.
I actually use a HamStick, since it can be used as a single band transmit
antenna in an emergency. Works fine on the stern rail since HF is not Line of
Sight limited.
"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? 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!




Larry W4CSC

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

I haven't actually heard any. All I have done so far is test it by swapping
connectors and listening near the right bands. Doesn't seem to be a high use
item.
(Larry W4CSC) wrote:

How many calls have you intercepted? I've only heard one, that
distress call off the French coast. Those frequencies are sure dead.

On Wed, 12 Nov 2003 05:26:21 -0800, sded wrote:

DSC reception won't work without the second antenna for the DSC receiver. But
since it is receive only, it can be any sort of simple antenna, like a CB whip.
I actually use a HamStick, since it can be used as a single band transmit
antenna in an emergency. Works fine on the stern rail since HF is not Line of
Sight limited.
"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? 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!




Larry W4CSC

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

Well, this is a powerboat. I have a SS forestay holding the mast up that I
could connect to, but the mast is grounded all over. I guess I need to
figure out another antenna to hook up to the DSC receive. The hamstick
sounds like it might be the ticket.

"Larry W4CSC" wrote in message
...
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!"

Since the DSC antenna on the IC-M802 is recieve-only,
i was planning on using the Furuno FAX-5 active antenna
which can be shared for multiple receivers.

The FAX-5 works with the new NX-300
LCD NAVTEX receiver, their more raditional thermal FAX/NAVTEX units,
and the new NAVNET "black box" Navtex/Fax receiver which
speaks (TA DA!!) IP!! it actually has a tiny web
server inside you can use to look at the pix and
the navtex! so how cool is that???

on our new boat, the FAX-5 will serve the Furuno fax/navtex
unit, an ICOM-PC1000 general-purpose receiver, and
the IC-M802 DSC input. 802 XMIT will be on a Digital Antenna
SSB stick with the 802's matching tuner. (AT-401??? i forget)

btw - i forgot to ask the Icom guys at Ft. Lauderdale, but
does the 802 come stock with the high-stability LO ??

-mo

On Wed, 12 Nov 2003 18:54:05 -0600, "Keith"
wrote:

Well, this is a powerboat. I have a SS forestay holding the mast up that I
could connect to, but the mast is grounded all over. I guess I need to
figure out another antenna to hook up to the DSC receive. The hamstick
sounds like it might be the ticket.

The forestay will work if the bottom end of it you're going to hook
the receiver to isn't grounded, too. Radio has a long history of
"shunt-fed" loop antennas, which is what that forestay would become if
you hook the radio between the open, bottom end of it and the ground
the radio is already hooked to, putting the DSC antenna jack actually
in series with the loop.....

Take a piece of coax and put a PL-259 connector on one end of it. On
the other end, strip off the shield and leave the center conductor
exposed but not so it can short to the unused shield. Clip it to
something handy on the bottom of the forestay. Now, plug this PL-259
connector into the regular antenna jack on the M802 and tune the
receiver from 2 Mhz to 30 Mhz, just tune around a wide freq range, and
see how well the forestay acts as a receiving antenna. Don't
concentrate on the strong SW broadcast stations. Listen around to the
weaker transmitters on the ham bands from 3.8-4.0, 7.2-7.3,
14.2-14.35, 21.3-21.45 Mhz. The low freqs will work at night, while
21 Mhz will be dead all night but some active in the daytime, so do it
at different times over a day. See how well it does as a receive
antenna. You'll hear if it sucks right away because you won't hear
normal atmospheric noise if it sucks. Might surprise you....(c;

Nothing lost in a little test but time.



Larry W4CSC

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

On Wed, 12 Nov 2003 21:02:07 -0500, Michael O'Dell wrote:


btw - i forgot to ask the Icom guys at Ft. Lauderdale, but
does the 802 come stock with the high-stability LO ??

Sure. It's the only way to get it to pass the freq accuracy standards
in its type acceptance tests.



Larry W4CSC

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