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We use an antenna tuner to feed our W8JK antenna for use for shortwave
reception for two reasons: 1. The 8JK has a high impedence input so it is fed with 300 ohm ladder line; thus the use of the tuner (in this case) acts as a balanced transformer. 2. The 8JK was "cut" for 20 meters. For use on other frequencies, the tuner acts (with adjustment) as a conjugate match that provides a 50 ohm input to the receiver. Results of the tuner appears to peak signal strength as the impedence of the receiving antenna is transformed by the matching provided by the tuner. Tuners are passive in nature; that is, they require no amplifier electronics and associated power. They may be unbalanced input to balanced output (or vice versa) or unbalanced to unbalanced input/output. Preselectors on the other hand are active devices. They vary in design and may provide matching as well as gain. The selection of the device you choose will depend on the type on antenna system you employ. In any case, good luck! John Sanjaya wrote: I've read and heard both sides of the argument about antenna tuners being great, or not helping at all and are a waste of money. I've been told they are only for shortwave transmitting, and I've been told they work well to improve shortwave reception on faint signals. I've had it suggested to me that I get a pre-selector instead. I can't find anyone who actually experimented with either a tuner or pre-selector... at least none of what I've read and heard was stated as "experience"... rather it seemed like theory or conjecture. Does anyone here actually use a tuner or pre-selector for shortwave listening, and if so, with what results? I'm looking at the MFJ-959C antenna tuner at http://www.universal-radio.com/catal...amps/2574.html Note that it says "for receive only". |
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