A 100mw TX capable of asymmetry modulation mounted in weatherproof box using a 3m base loaded or helical loaded whip over 16 or 32 stiff aluminum tube radial plane 10 ft diameter each radial being of equal length and opposite orientation to another radial and being stiff tubing prevents drooping. This should allow elevated install to perform like a ground mounted TX while being elevated above ground and radials should not radiate in this config and be in a sense a true elevated non radiating ground system. Power and audio can be rf filtered at am frequencies and ground can be filtered for am while allowing for DC ground for static and lighting protection. While the non radiating ground plane will act as a ground for TX monopole to work against
I think this idea sounds good. I'm not sure whether or not it would work (I'm new to radio, so I'm unsure about a lot of things). I hope it would work because I found a perfect location for my radio station. It even has a 60 foot radio tower (It used to be the home of WOBO-FM before they moved in 1996). If I had a chance to set up there, I'd need an idea like this. The FCC would probably shut me down with a 55 foot ground wire.
kc8gpd, I like the idea and it makes sense to me, but I have a question.
If you had that antenna, and an inspector saw it, what do you think he would think?
no clue. someone try it and see what happens. to me the plane should be considered ground since it is designed along with all lead up wires to not radiate only to act as a return for the main monopole to work against as if it were at dirt level.
since the power/audio and ground to dirt would have am frequencies suppressed via filtering they will not act as radiators.
What transmitters meet the specifications for this project, and how high up would be a good height?
any 50 ohm 100mW input to final tx with a LPF on output. basically a traditional base loaded or helical loaded monopole over a artificial ground plane with MW RF filtering on the audio / power inputs and some kind of MW RF filtering on static drain / lightning ground wire.
the point is to keep power /audio / ground lead / ground plane from radiating while still performing their respective functions in an elevated installation.
I think what's needed is clear definition of "ground lead" by the FCC instead of the guess work.
So far to date, there is no clear definition. Just a lot of debate and concept designs that may or may not be legal.
RFB
Yes, RFB, there is our stumbling block.
And also, I get the impression if I've listened correctly to past inspections, that some elevated installations get approved while others get shut down. That's confusing.
But I take a position that if MY elevated installation got approved, that from that day forward I could believe that whatever it was I did was correct, even if someone else got shut down for the very same setup.
If I am right in the impression I have, the whole thing is a lottery.
But I take a position that if MY elevated installation got approved, that from that day forward I could believe that whatever it was I did was correct, even if someone else got shut down for the very same setup.
Unless a future FCC inspector of such an installation has a different assessment of that system than whoever approved such, originally.
That's when things are not fair, rich, when the second opinion over-rules the first.
How can a part 15 operator ever know how to get a fair outcome?
There have been so many posts written in earnest concern over the grounding issue, the part 15 stations really want to do it right.
How can this ground vs height problem be resolved so folks at least know what is ok and what is not?
Do we need to occupy the FCC?
That's when things are not fair, rich, when the second opinion over-rules the first. How can a part 15 operator ever know how to get a fair outcome?
All of us are subject to the enforcers of the law, as such entities detect/evaluate/judge us at a given time.
As an analogy, some auto drivers may not be ticketed by a police radar measurement showing a speed of X miles above a posted limit.
But that doesn't mean that such persons are immune to penalties by the law enforcement process for measurements above that same speed limit, for future infractions.
So if unlicensed operators in the U.S. wish to avoid all possibility of FCC actions related to Part 15, they need to understand and observe the technical realities that apply.
Sorry to be blunt, but sometimes that is needed.
With speed limits the posted number is specific.
With part 15 in regard to grounding in the situations under discussion, there is nothing specific in the rules whatsoever.
As for the audio/power lead ground
question - can't you just throw
another radial out the other side
to cancel it out?
Man, am I full of weird ideas.
And as mentioned before - my Part 15
station is low key, and my publicity
campaign is just word of mouth. I
feel that's it's safe that way. I
have had listeners, and the station
is just one of a bunch of other stations
on the dial.
Time to go to bed. Gee, I said that
about 10 minutes ago in another thread.
Bruce, DRS2