TheRadioBoard

Has anyone had experience with this commercial loop antenna?

I am a bit skeptical as it covers all bands with "no tuning."

http://www.highgainstore.com/rf_pro1b_loop_antenna.html

Seems like a lot of money ($446) for a loop and pre-amp

Rich

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Homebrew Radio ex-Silicon Valley

Possibly related:


Circuit and details:
http://lz1aq.signacor.com/docs/wsml/wid ... ntenna.htm

As qrp-gaijin notes, it's a shorted turn acting like a voltage probe. The balanced amp makes electrically induced noise common-mode. The Moebius loop doesn't seem to make a big difference over the competition (according to the Clifton Labs tests), and I didn't see any patents listed, so there's no new art here. With such low radiation resistance, most of the cost probably goes into making low-ohmic-resistance, weather-resistant connections to the loop. The preamp should be a piece of cake. A CATV transistor like the 2N5109 would do for most of the gain, and a FET input stage would handle impedance transformation.

Note that the preamp uses 20 V (for high IMD performance) at 240 mA, or nearly 5 W. That correlates with a high-current bipolar amp stage. I'm sure you could duplicate this antenna for a lot less than $400.

73,

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http://kr1s.kearman.com/
http://qrp.kearman.com/

The HDLA antenna made by Charly Hardt is a similar antenna. Charly is a well known German dealer for SWL's and DXer's supply.
http://www.activeloop.de/html/english.html
I own the HDLA3 and I am able to recommend it. I use it in my garden or mobile/portable. I am about to buy another HDLA for my attic, probably a HDLA12.

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73 de Fritz

--
<b>Radio geht ins Ohr, Fernsehen ins Auge.</b>
<i>Robert Lembke (1913-1989)</i>

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