PIROD tower company has been around for a while, thus there are likely many of these tower light controllers out in the field. They perform a vital service in controlling and monitoring tower lights at remote transmitter sites maintaining a safe operating environment for aircraft and compliance with FCC rules.
PIROD was sold to Valmont in 2004, Valmont no longer manufactures or supports the product. All is not lost, however, as XCEL Tower Controls does support it and parts are still available through them.
These units were fairly rugged, had good surge suppression on the incoming AC lines and are designed for easy access to service parts.
This particular controller is being installed at WRKI in Brookfield, CT. We are adding toroid cores to the tower lighting circuits coming off of the tower because the last controller has been mostly destroyed by lightning. It is a tall tower, on top of a tall hill, thus it gets struck by lightning many times over the course of a year.
The block diagram looks like this:
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The basic schematic looks like this:
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The entire manual can be found here, (medium sized .pdf) courtesy of John Brickley of EXEL tower controllers.
There is a picture somewhere, of the WRKI tower after being hit by lightning, the top bay of the ERI antenna on fire. I had it emailed to me a while back, and probably still have it somewhere.
WRKI still has a fantastic signal, covers a nice chunk of Connecticut very well.
I grew up listening to them in Great Barrington, MA. (Where their signal is solid.)
Mike, I have that picture somewhere also. I looked at it a while back and it is very grainy, plus, I don’t know who owns it. It would be nice to get the original and permission to do a post on it, it is a great picture.
WRKI does have a good signal, I listened to them in Dutchess County NY when I was growing up.