ELT and Comm antenna placement

[Greg Bockelman]

I need to install an ELT antenna on my Stinson. As I understand it, the ELT antenna should not be placed within 36 inches of the Comm antenna. However, there is already a mounting location on the airplane but it is 33 inches aft of the Comm antenna. How critical is this spacing? It is possible to get about 43 inches spacing but there isn’t sufficient support there unless I put some sort of doubler there. However, doing that is rather problematic.




Now, as far as the ground plain goes, mine is about 4 feet long by about 6 inches wide. Is that sufficient?

 

[Bell206]

How critical is this spacing?

The 33 should be fine. A quick check for bleed over into other freqs should double check it.

Is that sufficient?

I usually follow the OEM guidance. but 6 inches seems a bit narrow. There are formulas to figure the size out for maximum antenna performance.