Build Your Own FM Antenna___________________________  


In the last two years, I've found approximately three DIY designs for building your own FM antenna, since I don't model them myself. I wanted something roughly equivalent to the discontinued APS-13. It's the best consumer-grade antenna I've found, in terms of gain and front-to-back ratios. Quite a few radio stations offer some excellent designs, but they're narrowly focused on a particular frequency.

So, here are the links.

 
Antennas and Theory in General  

The (old) Cebik site had some great information: one, two, and three.

http://sumtechantenna.freeservers.com/ is a great Australian site. The ZL105 antenna is the FM version. However, this particular antenna is centered at about 105 mhz. For the US, the author of the site said to multiply all the dimensions by 105/98, or 1.07, to center it at 98 mhz. He said rolloff is different at high and low ends, so the center point can be adjusted easily with the math. His other antennas also require some conversion to work with the US bands.

Brian Beezley's site is another excellent read. He models quite a few antennas for gain and reception characteristics, including the APS-13.

Another great site, much information about TV and FM antennas from KYES in Alaska.

More useful, basic information. Covers HDTV primarily, but it applies to FM reception as well.

 
Materials  


These are places that offer the most reasonable prices on pieces for your new creation, assuming you can't find something local. I'd like to know about better attachment hardware options. DXEngineering has the goods, but it's for the trade, not necessarily for the DIY market.

Texas Towers: 6061-T6 aluminum tubing. Best prices I found, though they don't have 0.25" round stock.

AirParts, Inc.: Aluminum tubing

DX Engineering: Some connectors, clamps, baluns, cables, etc.

Ken Wetzel's low-loss balun construction.

 

 

 

25mar12