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Old September 29th 11, 01:15 AM posted to rec.radio.amateur.antenna
Jeffrey Angus[_2_] Jeffrey Angus[_2_] is offline
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First recorded activity by RadioBanter: Aug 2011
Posts: 47
Default LDG Z11 Pro II tuner with an Icom IC-761

On 9/28/2011 7:00 PM, Owen Duffy wrote:
I think your question relates to the connections between the LDG and that
Molex plug.

Was it LDG who supplied the adapter? If so, ask them. Seems a bit silly
that would supply the thing without adequate information on how to use it.

Owen


Well, I did ask LDG and they were kind enough to send me the application
note describing the connections.

And the more I looked into this the more I realized, "You have an
antenna tuner built in into the Icom IC-761."

Homer Simpson moment, "Do-oh!"

However, the specified tuning range of the internal tuner is 16.7
to 150 ohms. The LDG is specified as 6 to 1000 ohms. A bit more
latitude.

OK, "How did I get side tracked like this?"

Earlier this year I got an MFJ Versa Tuner to use with the doublet
antenna. It works fine. But of course, it's manual. (But it does
have a 4:1 balun inside.) So I get the LDG in a swap for some
goodies. No balun inside. Ok, I ordered an MFJ 4:1 current balun.
And those do work a LOT smoother tuning that with the internal
4:1 voltage type the MFJ tuner has.

It was while obsessing over the "talk to the radio" cable for the
LDG that I realized, "Oh right, this is designed for radios that
don't have internal tuners." For example, my Icom IC-726 has the
correct interface to talk to the LDG. I do have the matching AT-150
auto-tuner for the IC-726. That is specified the same as the IC-761
tuner.

Once the balun gets here, the FIRST thing I'm going to do is to
find out if the internal tuner has enough range to deal with my
antenna.

I just love wild goose chases, because in the end, you usually do
learn something useful in the process.

Jeff-1.0
wa6fwi



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