Thanks for the quick reply Dan.

Have you updated the FLARM to the latest firmware (6.60)?
Yes. Both units are running 6.60
What kind of coax did you use to connect the antennae to the FLARM and how long are the runs?
Aviation quality and about three meters
Have you tried a factory reset of the FLARM?
Yes. Its just back from being reset. But they admit they didn't check the freq performance.
Does the towplane have a metal tint on the plexiglass windscreen?
No

I haven't ever seen the frequency offset move that quickly.

We had a FLARM CORE in the club which went for repair and the transmit section was replaced; it could only be seen for 100m or so. Now, range like all the others (OGN ranges of greater than 40 km).

A great resource is the forum for the OGN; it is at https://groups.google.com/forum/#!fo...nglidernetwork . Details on joining it are at http://wiki.glidernet.org/contact .

Cheers
Dan

I have sent the above data to the OGN people but no reply from them as yet either.

Paul