[BC] AM transmitter lightning sensitivity issue

[Craig Healy]

>  From what I am gathering from other sources, this
> "storm sensitivity" appears to be a characteristic
> of this particular transmitter.  But I wanted to throw
> this out there to see if others have experienced a
> similar problem, what they may have done to help
> minimize or solve it or offer suggestions as to what
> else I should consider.

One of my clients has a Nautel Jazz 1000 and did have an older SX-1 backup.
When storms came around, neither would stay on even if the power was dropped
to a hundred watts.  Snowstorms also caused this.  And, it's in a flood
plain and occasionally has the river water up above the tower base
insulators.

The older RCA BTA-1R1 just ignored all this stuff and only tripped off when
there was a direct strike.

What I ended up doing is modifying a dummy load into an attenuator of about
5.5db.  That's now between the backup transmitter and the system.  With that
in place, there has not been an outage or even a blip.  At 5kw that would be
a much more involved fix, but if you have a kilowatt backup available, it
may be worth a try.  The attenuator was a normal Harris model, and the
additional resistors came from a surplus shop.  I think they were 100 ohm.
It's a situation where some coverage is better than no coverage.

I can dig up the schematic, if desired.  It was a simple build, taking maybe
an hour.  The replacement Jazz 1000 is perfectly happy running into that
with zero VSWR shown.

Craig Healy
Providence, RI