Total posts : 45366
I’m sure many are interested in the effect of an elevated ground plane. Hope you can report some definitive results soon.
I vaguely remember your original post about your elevated antenna but can’t easily locate it. You mention you may have a tuning problem. This triggered a sensitive spot. I get the impression that many part 15 enthusiasts don’t quite grasp the importance of tuning an antenna. I’m not saying this about you! Just siezing the opportunity to disseminate a little info to everyone.
Short vertical antennas (this is the terminology for our part 15 restricted crippled antennas) have by their nature a very sharp tuning peak. If they are tuned just a little off frequency, range will drop dramatically. The tuning peak is similar to what you experience with an analog-tuned AM radio receiver. As you turn the dial, the signal peaks and then goes away quickly. Likewise, if you don’t tune your antenna to its absolute peak, your range will go away quickly.
Because each transmitter user has a unique installation with respect to height, ground and who knows what, tuning is unique for each installation. Any deviation from the manufacturer’s recommended installation can cause tuning problems.
You absolutely MUST tune to the pronounced peak as indicated by your transmitter’s meter output or by a field strength meter reading. If you don’t get that pronounced peak or you get some sort of gradually rising reading, but not a peak, something is WRONG. Go no further. Fix whatever is wrong with your installation before proceeding.
[quote:83038dd471=”broadcastman”]Thanks for asking.
I haven’t had much time to work on it.
I did try adding 5 radials in the position it is in and then retuned it buy it did not help. I think I do need some help with tuning, though.
I am going to move it as soon as I can to the center and put in some radials and find someone to help tune it, and if that does not work, I don’t know what I will do, as I was expecting a lot more than I am now getting.[/quote:83038dd471]