[BC] am receiver for monitoring at a 20 KW site.

[RichardBJohnson at comcast.net]

You are going to need a well shielded receiver and I do not think they are made anymore! If you can get your hands on an old Hammarlund Super Pro that still works, you are halfway there. In the "olden days" when we needed something special like this, we'd build our own.

If it was my task, I'd start by getting a metal box or make a wooden one, completely lined with metal screen or aluminum foil. Then I'd add a line-filter that is "grounded" to the metal box. The idea is to shield the receiver of your choice so it receives nothing at all.

Then, I would make two tuned loop antennas, fed with 75 ohm coax, with its connector connected to the metal box. One of the antennas would be inside the box, and the other would be outside, oriented to the station you want to receive. Old fashioned 360 pF compression tuning capacitors are still available. They would tune the loops. The loop antennas have a one turn loop that is connected to the coax. The rest of the loop antenna consists of enough turns (loops) of wires to resonate with your tuning capacitor. You can "wind" the loop antenna on a piece of Masonite with a bunch of saw-cuts, just like they did in the "olden" days. Do not try to use a feri-loopstick. It will be nonlinear in high fields and cause cross-modulation.

Cheers,
Richard B. Johnson
Book: http://www.AbominableFirebug.com/

----- Original Message -----
From: "Lotus Engineering" <loteng at lvradio.com>

Can anyone recommend a reasonably priced AM receiver that can set at a 20 KW AM site and monitor a 5 KW AM station about 1.5 miles away without having a lot of bleed through?