Small coils

[D&P-OR]

Which one of these 2 coils is going to be the best "trash working" coil on the F-75 LTD--the 5" DD or the 3X6" concentric?

 

[go-rebels]

I wrote a large write-up comparing these two coils on NASA-TOM's site, which is now down.

Bottom line: Both are equally good and show equivalent depth. The 3x6 that you speak of is really 4x6.5 (commonly the 4x6). The concentric 4x6 IDs bottle caps better but the 5" separates better due to its round shape and beam pattern. The 4x6 covers more than 20% area per sweep, which shouldn't be discounted. In old sites I use the 5"; in newer sites I use the 4x6. For the 1st coil, I'd buy whichever is cheaper, or the first available if you are having trouble finding either.