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Here we have a compact antenna tuning unit and SWR bridge that was custom built for the 136 kHz band. It was used with LF receivers and with transmitters running up to 400 watts during the period 1998 and 2001, but it hasn't been used since that time. The unit also includes an antenna switch so that the TX/RX can be switched between either the loop antenna or through to a second antenna. This ATU is intended for use with single turn loops. In my case, I used it with a 200 ft perimeter loop to resonate it to 136 kHz, and to provide a 50 ohm match to the TX and RX. This ATU is not for use with long wires or marconi antennas. This tuner might also perform well on 500 kHz, or at least provide a good starting point. The tuner includes a balun with a 3C85 core; SWR Bridge; 100 uA moving coil meter; power indicator (not calibrated); antenna switch; capacitor strapping field (to 'coarse tune' the loop using a range of large value capacitors); 'trim' switches (to switch in small values of capacitor); and sockets for an optional external variable capacitor (for fine tuning). http://www.alg.demon.co.uk/radio/136/loop_atu.htm http://www.alg.demon.co.uk/radio/136/loop.htm Please see my other adverts for lots more interesting things. (please look at our rules and privacy policy) |
Etta.bryan@machine--tools.com (Etta Bryan) for additional information. This email is used for forwarding to newsgroup user.
