Post subject: Questions about tunable loop antennas
Posted: Apr Mon 09, 2012 3:03 pm
Joined: Aug Tue 30, 2011 11:25 pm Posts: 930 Location: Charlevoix, Michigan, USA
I am thinking about building a 1920's-style tunable loop antenna. I have seen two different types: the kind where all the windings are the same diameter and run parallel to each other, and another where the windings run in a decreasing spiral towards the center.
What are the advantages and disadvantages of each type, putting aside construction complexities?
Is one type "earlier" in time-period than the other?
Was one type used with certain circuits more than others?
Are there any plans available for building each type?
I already have enameled magnet wire. Would one type of loop work better with that kind than the other type of loop? I would likely be using 30-gauge wire, as I have the most of that kind.
Performance of a loop antenna is going to depend somewhat on location. I have never built a spiral (helix) loop. All of mine use parallel wires at the same radius. Lots of old-style loops were spiral wound. See Dave's pages above.