The BC-939(*) antenna coupler, is not an antenna tuner, it couples the RF from the transmitter to the
antenna only. It does this by presenting a 50 ohm load to the transmitter, and then passing RF on to the
antenna, which can be either an end-fed long-wire configuration, or a 15 foot whip, fed at the base.

Lots of folks that have tried to use these "COUPLERS" have complained that they don't work! I have
found that those individuals, in most cases, did NOT have the manual, that explains how to use the item
properly, and also what types of antennas it works with. The manual calls for a long-wire antenna of about
44 feet, with the end of the antenna brought to the output connector of the BC-939(*). If you are using a
vertical whip, as in a mobile situation, it is ideally suited to a 15 foot whip, fed at the base, and will couple
the signal to the whip over a range of 2 - 18 Mhz. The same is true of the long-wire, the range is 2 - 18 Mhz.

In all instances, a GOOD ground connection is essential, if the rig is setup in a building environment, make sure
you have a good earth ground connection. I use an eight (8) foot ground rod copper clad steel, in the ground
right outside the window of the shack. The ground lead, should be as short as possible, mine is 6 foot long, to
the outside ground rod. I also use a 15 foot whip on my Chevy van, and the ground goes through the main
chassis frame, under a 1/4 inch bolt. Clean the chassis point, and use star washers on both sides of the mount
to the chassis. The ground connection can go to the coax feed point on the left side facing the unit. Beware, the
ground connection is the front most screw terminal.

The unit is ruggedly built and can safely handle 15 RF amps into the antennas described above. Note: if the
coupler is not physically grounded, the center of the handles used to tune the unit WILL be RF HOT! Beware
RF burns are real bad stuff, and hurt like heck. However with proper handling I find both of my units to be
good performers, and a real advantage to the limited antenna space problem.

Here is the military "Line Drawing of the front panel of the BC-939(*) Coupler.

When I go on "Field Day Trips" with the Big Rig I take a portion of the military AN/GRA-4 system. This
system consists of three vertical pole sections, approximately 40 feet tall, guyed with nylon ropes and it
is easily erected by one person in about 40 minutes. I carry a base loading insulator for the system, and
also a 40 foot counterpoise system consisting of 4 wires 44 feet long. I use the center conductor of RG-8/U
coax, as the feed-line and raise the feed line off the ground with 4 foot fencing stakes (made of wood).

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