REFLECTOR: Transponder Signal Strength Anomaly - Recommendations for Replacement

[Gary T. Ciampa]

All,

I'd like to describe an anomaly that occurs with my current transponder 
and solicit recommendations on a solution.

So: I have an epoxy circuit board dipole transponder antenna that is 
mounted along the right-side of the fuselage, in the nose compartment, 
about twelve inches foward of the canard bulkhead. The anomaly that I've 
encountered is when flying directly away from the radar station and 
somewhere around 40-50NM from the station, the contollers lose my 
transponder signal. I can change my aspect to the station (turning the 
airplane about 30 degrees) and the controllers re-acquire my transponder 
signal. Upon resuming my original course, controllers lose the signal. 
I've tested this scenario with multiple controlling agencies, in several 
cases, doing a 360 while the *accomdating* controller keeps me apprised 
of the transponder status. Additionally, heading towards (or flying 
abeam) a station, I have never had a problem with the controlling agency 
picking up the transponder from one-hundred plus miles, which seems to 
rule out a signal strength problem.

Question:
Is this a generally known problem with pushers? (I'm assuming the 
engine/firewall is attenuating the signal aft of the airplane)

Is an antenna such as the AV-22 a suitable substitute?

I was planning to locate the AV-22 somewhere along the bottom of the 
fuselage, perhaps between the nose-wheel strut and speedbrake. Is this 
satisfactory? (this location is purely for convenience as I happen to 
have the canard off for an inspection and sufficient antenna cable length)

Other recommendations?

Thanks in advance for your advice....

Gary