How to measure Antenna Spacing

macrafic · #1 03-24-2010, 03:16 PM

Question for you all. When it is said that antennas should be 3' from one another (or 18" or 24" or whatever), how is that measured? From the base of each antenna or from any part of the antenna.

Of particular concern are the bent whip antennas, since the end of the antenna is just under 2' from the base, which is significant when determining your spacing.

Mel · #2 03-24-2010, 03:43 PM

Basic "rule of thumb" is that no metal should be within the length of the antenna from the tip.
i.e. if your antenna is 24" long, there should be no metal or other antenna closer than 24" to that antenna.

Camillo · #3 03-24-2010, 04:26 PM

Little off-topic.
I had to plan 2 COMM's, 1 DME, 1 XNDR, 1 ADF, 1 DME, 1 GPS, 1 ELT.
Headache to let all of them properly distanced in a short plane as an RV.
But I did it. Well, DME is under the tailcone. Obliged me to use an RG142 cable.
I also wondered if distances would have been computed from the most aft/fore metal part of each antenna. I hope slight under-distance will not make the difference.