At 14:59 10/05/01 Thursday, Andy wrote:

The local Non Directional Beacon here, EAS at Southampton Airport on
391.5kHz, puts out strong odd order harmonics.  The fifth harmonic on
1957.5 actually caused QRM once.  The third harmonic is masked by a
local broadcast station at my QTH, but would probably be a problem to
listeners nearer the airport.

Does anyone know the internal design of these NDBs- wouldn't surprise me
if they drive a squarewave to their (what looks to be rather small)
antenna.  In which case how do they generate the AM ?

Maybe they're still using a T1154 - they were notorious for this problem!

Walter G3JKV.