RE: LF: harmonics / LF antenna

["Walter Blanchard" <blanch@pncl.co.uk>]

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.