eBay and other sources list a range unpowered (not active) antennas for general-coverage use. These are electrically-short whips or loops that are ostensibly impedance-matched to 50-ohm coax and feed the 50-ohm antenna input of receivers. They boast flat response from kilohertz to maybe 30 megs. Does anyone here have actual experience with these, to the extent that you can judge the relative performance against long-wire or active antennas? Any info on what sort of matching network is used on these would be welcome too.
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The Radio Board.org
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I'll be a way for a few days but will definitely fire this up before or during the coming weekend. That translated blog is interesting, and brings up a point I'd wondered about; that is, the length of the lead-in. The antenna comes with what looks like 20-30 feet of RG58, and the instructions don't touch on additional length. That's probably enough to get out of a noisy home environment, but not enough for a roof mount here. I would think that, "matched" to a 50-ohm line or not, additional cable capacitance would tend to negate the advantage of any passive impedance-matching in the sealed antenna base mount. I ran across a rather comprehensive overview of active E- and H-field antennas at g8jnj.net that seems to answer a number of questions.