W aircraft antenna explanation

[K6JEK]

A private pilot friend of mine came by with a picture of an aircraft com antenna, "Bob Archer's W"  How can this work? he asked.  Although the feed wasn't obvious I guessed it was a dipole and said that bending the ends of dipole doesn't have much of an effect on performance.

But I can't really answer how it works because it's not just the ends that are bent.  It bends right in the middle.  It doesn't really look like a W either.  I might have been able to fumble my way through an explanation of something that really is a W. 

Take a look at this thing?  How does it work?

[KD6VXI]

http://home.hiwaay.net/~sbuc/journal/bob_archer.htm

Dipole, bent to fit.

That "assembly" you see attached is a gamma, of some sort.

--Shane

[K6JEK]

http://home.hiwaay.net/~sbuc/journal/bob_archer.htm

Dipole, bent to fit.

That "assembly" you see attached is a gamma, of some sort.

--Shane

Thanks.  That makes sense.

[KM1H]

I designed and built many like that, at one of my jobs, for microwave frequencies. Several were on a PC board and that center part was a stub tuned to match them all to a 50 Ohm line. Etched on board power dividers and phasing lines were easy at 5.8 gHz. One of the prototypes I made is at the 120' level of the big tower for 8 years for my Internet link.

Carl
KM1H