[BC] AM transmitter lightning sensitivity issue

[Thomas G. Osenkowsky]

>Harris does have a tech note (AM-409-TLH) that addresses this issue through
modification of the >VSWR detect circuitry to increase the time constant of
detection and reduce the VSWR sensitivity >threshold.  I have been hesitant
to implement it mainly because we presently experience occasional >blown PDM
amplifier fuses and/or FETs when the transmitter does experience a storm.
To >bulletproof the VSWR detection circuitry may increase this failure rate.

The "TLH" stands for Terry L. Hollenberg, former
Field Service Supervisor at Harris. I was the first
SX-1 to install this mod. Change the word "may"
in your last sentence to "will". We blew several PA
MOSFETS with the mod. I removed it.

As others have suugested, ensure you have intact
static drain chokes at each ATU. If there aren't output
capacitors in the leg of the Tee networks, install one.
Not so great a value of Xc that requires a lot of coil,
but enough to block DC. Also, you must have a strap
from each tower base back to the phasor and transmitter.

Tom Osenkowsky, CPBE