On Tue, 11 May 2004 02:37:46 GMT, tony roberts
wrote:

Thanks very much for all the advice.
It looks as though loop antenna is most likely, with radio interference
as the second most likely. I'll fly it with everything shut off to see
if the problem persists, to help narrow it further.

To respond to the questions that were in some responses,
if a fly a 360 the needle tracks the NDB if I am near it, but not if I
am several miles away.

Nospam asked if my crab angle was 30 degrees. No. If the NDB were ahead
of the nose the needle pointed at 330, regardless of whether the NDB was
at 300 degrees or 40 degrees.

Thanks again for all the advice - I'll post the solution when I have it

Tony

As has alrady been suggested it may be interference, since it works
close to the NDB.

You say ' the needle tracks the NDB if I am near' so have you listened
to the audio out of the ADF receiver? Maybe you can identify some
interference.

Sounds like a similar problem, we had, which was due to alternator
noise (a whining noise which varies with engine RPM). In our case an
alternator decoupling capacitor had not been fitted with the
replacement alternator which did not have an inbuilt suppressor.




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