Happiness is: An AM directional array at licensed values

Last week I did some repair work at WDDY in Albany NY. It seems the sample line on one of the towers was melted in half by a lightning strike. This station uses sample loops up on the tower for its directional antenna monitoring system.

WDDY antena array, Albany, NY
WDDY antena array, Albany, NY

As it happened, the sample line in question was on the reference tower, which makes everything else meaningless.  Before the meltdown, there were several years’ worth of maintenance logs that showed the previous values for current ratio and phase relationship.

With the transmitter turned off and locked out, I removed the damaged section of the line from the base of the tower to the RF choke coil in the tuning house.  Where the sample line came off of the base of the tower, there was a UHF-type connector that had been improperly applied.  Using spare parts, I fixed that connector, then spliced the line into place.  Upon power-up, the transmitter and antenna readings returned to their previous values, which were slightly out of tolerance.

Thus, some phasor tuning was needed.  There are not too many people left that can properly tune an AM phasor.  All of the control interact with each other; moving the power or phase to one tower will likely affect all of the other towers and possibly the reflected power on the transmitter.  This phasor was made in the 1970s by Multronics with what looks like all RCA parts.  Multronics, I think, was John Mullaney who is more known for the folded unipole antenna.  In any case, after a good few hours of careful hand cranking and a run out to the reference tower to move a coil tap, here are the results:

WDDY tower one, reference
WDDY tower one, reference
WDDY tower two
WDDY tower two
WDDY tower three
WDDY tower three
WDDY forward/reflected power
WDDY forward/reflected power

Not bad for a day’s work.