Well I had an idea.
What if I added metal underneath my FM transmitter.
Well I had an idea.
What if I added metal underneath my FM transmitter.
So I took a sheet of aluminum foil and placed it under the FM transmitter. Without the foil with my radios antenna fully collapsed I would lose the signal at the end of my fence. with a signal meter reading of 2 (about 5db)
(of course if the antenna was stuck out at all the signal would immediately come back with a vengeance)
With the foil ground plane the signal shot up to about a signal meter reading of 3 (-10 db)
This was quite a significant difference. SO i figured, why not add more foil!
SO I added more foil and took another reading. The meter was now reading about 4.5 on the meter (darn near -60 db!)
I'll have to do a signal test tomorrow to see if I get out better. If the backyard proved to be that much different I can only hope its that much different for the neighborhood.
Looks like even a little bit a foil can help get the most out of our little FM miliwatts! More results tomorrow!
The Crow I am glad you opened this subject at this time, because I have been looking at my 4-element cage monopole and becoming concerned that I never designed a ground (other than that supplied by power and audio connection). At 101.9 FM with Wholehouse 2.0 the signal doesn't do very well, but maybe a well planned ground would pick things up.
Alrighty,
Heres the results!
The Verdict, POSITIVE!
The ground plane has made a noticeable change in signal quality.
Improvements are noted
Better Building Penetration
Improved signal distance
Improved ability to resist interference
Improved resistance to multipath
My signal would always abruptly cut off at the stop sign at the end of the street. With the ground plane in place the signal is now, although slightly staticy,listenable over the little bump at the stop sign. I noticed when cruising the side streets the signal had a better time going through the buildings then previously before, and that me walking through the house no longer causes multipath on the signal.
Overall I say a ground plane (even a cheap tin foil one) is a Must need for the part 15 FM broadcaster wanting to get the most out of his miliwatt.
Same reason antennas on cars roofs improve the signal. However in that scenario, the transmitter is connected to ground through it's power connection, so the metal roof is also ground, and forms a decent ground plane.
If your foil isn't connected to good ground, try that and see what happens.
Thank you The Crow for your report. I am convinced now of the need for ground systems designed for the antenna/frequency band being used.
Well, almost everyone else already knew this, but I am just now catching up on ground.
There should be a dedicated course in tech school:
Ground 101
Good grounding is always important, especially for safety, but ground planes (above ground) are a bit different than say ground radials. Higher RF frequencies don't need it so much for good propagation. Cell phones, small handheld transceivers, etc., don't need massive ground connections, but your body can help a little.