Hi David! I have this problem with my hand held antenna analyzer too. I figured out that it was picking up AM and FM ( and maybe TV ) broadcast signals and those were interfering with the readings.
I now use my LP-100A RF meter with about 5 watts of RF to get accurate readings. Yes, lugging a QRP radio and RF meter out to the antenna is not near as handy as a small hand held RF analyzer, but at least you get stable, reliable and repeatable results. http://www.eham.net/reviews/detail/5981, http://www.telepostinc.com/lp100.html 73 Lloyd - N9LB -----Original Message----- From: Topband [mailto:[email protected]]On Behalf Of D Rodman MD Sent: Monday, December 03, 2012 10:22 PM To: [email protected] Subject: Topband: Delta Loop vs Antenna Analyzer My 160m antenna died several weeks ago from a bad coax feed line and was restored just Sunday after the contest. I have tried several antenna analyzers and none seem to work with the loop antenna. I designed the antenna for 100 ohm feed and always wanted to put a half wavelength coax on an analyzer to measure R and J to achieve the best match. Calculated series transformer of 50 and 75 ohm coax seems to match the antenna quite well as anticipated. But, no matter how I try with any of my many devices, I can't get the boxes to work with the loop. The readings are not consistent. They just don't seem to like the antenna. Other wire or yagi antennas work as expected. Questions about if others have tried to measure loops or theoretical reasons why the various devices can't read the impedance are obvious and responses welcome. Thanks. David J Rodman, MD Assistant Clinical Professor Department of Ophthalmology SUNY/Buffalo Office 716-857-8654 _______________________________________________ Topband reflector - [email protected] _______________________________________________ Topband reflector - [email protected]
