[SECC] Survey

[K4SB]

Guys, regarding Gary's survey of how to hook up external Rx antennas,
the rig modification is very simple.

Basically, all you have to do ( and this is for rigs without the Rx
feature ) is to add ( if not already there ) 2 phono plugs to the back
of the rig. If you find there are unused plugs ( such as phone patch,
ect. ) that you are not using, simply disconnect the wire to that
plug.

Now, most rigs have a grounding bolt and nut on the rear. If this
opening is anywhere near the TX/RX relay, relocate it to some other
place, and place a phono plug there.
Otherwise, get out the drill and make a hole for a phono plug. Now, at
this point, we have 2 unused phono plugs on the rig.

At the relay, unsolder the wire going to the first RF stage. This is
simple to find as it is the one which will show continuity with the
main antenna plug. ( assuming you don't have the rig on and in
transmit Hi )

Solder that wire ( and it's usually a very small piece of coax ) to
one of the phono plugs. Mark this phono plug "1". Solder a similar
piece of coax from the OTHER phono plug to the relay where you removed
the original wire. Mark this plug "2"

And that's it! Well, as far as the mods go.

Now, make up a jumper and connect it to the 2 phono plugs and the rig
is right back where it started. The route is 1st RF to phono plug 1 to
phono plug 2 to relay, and to 1st RF.

OK, to use external antennas, get a 3 or 4 position A/B switch from
Radio Shack. The type used to switch TV inputs, ect.

Remove the shorting loop, and connect a cable from the phono plug 1 to
the COMMON of the A/B. Connect a second cable from the A/B to the
phono plug 2. At this point, we are right back where we started.
Selecting "A" will act the same as the loop between the phono plugs
did, you are receiving from the Transmit antenna, and everything is as
before. However, and let's say this switch has A, B, and C positions.
"A" is our 'Normal" position. But, by connecting an external antenna
to either the B or C positions and selecting either will route the the
external antenna directly to the first RF. So, we now have normal, and
RX ant 1 on B, and RX ant 2 on C.

It is CRITICAL that you have the common of the A/B box routed to the
plug which has the new cable connecting to the T/R relay where you
removed the wire.

Want more external antennas? Get another A/B box, and route position B
of Box 1 to the COMMON of A/B 2. The remaining positions of A/B 2 all
go to external antennas.

BTW, the explanation is about 100 times as complicated as the actual
work.

73
Ed

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