[TowerTalk] Prop pitch magnetic reed switch

[Peter Chadwick]

Mel said:

 >It appears  the contacts are sticking... or it is possible the switch
itself has become magnetized?  Maybe just enough to hold them closed until
subjected to a slight vibration?  If so, is it possible to degauss the
switch?<

My experience with reed switches is that sticking is often caused by  too
much current, or a reactive load which las led to arcing and the formation
of a 'pit'  on the reeds, and then mechanical sticking. The best answer is
replacement. How much current is it switching? If the load ends up very
capacitive because of long leads and RF by passes, consider putting a
resistor in series with the reed, right up at the contacts.

The old telephone exchange in the village about 5 miles away used to be reed
relay based, and it was very prone to having a the reed feeding my line get
stuck after any close thunderstorm. Funnily enough, now there's a
semiconductor SLIC on the end of the line, we don't get any problems (touch
wood!)

73

Peter G3RZP