The Unglorious task of Vermin Control

Warm, unmanned buildings in the wilderness are very attractive to all sorts of uninvited guests; mice, rats, snakes, insects, etc. Unfortunately, these can do damage to equipment, as evidenced here:

Mouse infested power panel, remote transmitter site
Mouse infested power panel, remote transmitter site

Thus, some steps need to be taken to secure transmitter sites, generators, outbuildings and even vehicles from mice in particular. Mice can squeeze into a hole that is .7 inch (17 mm) in diameter when they are full grown. In many transmitter buildings, this leaves lots of opportunities; coax feed through ports, ingress holes drilled for wires, electrical service entrances, cooling fans, gaps under doors, soffits, etc.

Many people simply call the pest control people who will come and put poison out. That does not solve the problem and can in fact make it worse. If the poisoned mice go outside to die, they are eaten by the snakes and birds that naturally control mice in the wild. Those animals then die from the poisoned mouse. Meanwhile new mice are being reproduced every 20 days or so. Fairly quickly, the bait is consumed, the mice no longer have any predators to naturally keep the population in check and there is a mouse explosion.

Hole in cinder block building covered with aluminum rack panel blank
Large hole, formerly a vent for propane heater, covered with aluminum rack panel black.

The best way to keep them in check is to seal up building as much as possible. For some reason, coax entry ports are often left open. This is very easy to fix and whenever tower crews are running new lines, ensure that they apply the correct boot for the port and line.

Replacement door jamb
Deteriorated door jamb replaced with pressure treated wood

Another thing that happens; door jambs deteriorate or the bottom of steel doors begin to rust away. This opening is very attractive to insects, snakes, mice and even plants.

Screen covering generator ventilation opening
Chicken wire screen covering generator ventilation opening
Generator radiator opening covered with chicken wire
Generator radiator covered with chicken wire

Generators need special attention. Radiator and ventilation openings should be covered with chicken wire. This can be attached to the metal housing with self taping screws and fender washers. Be careful and look inside of the housing to make sure that the area inside the housing where the screws are being applied is clear of wires and hoses.

Stainless steel pot scrubbers filling space around conduit and pipes
Stainless steel pot scrubbers filling gaps around conduit and fuel line

Ingress for fuel, control and electrical conductors need attention as well. I found stainless steel pot scrubbers to be effective for filling gaps around these conduits and pipes. They are available on Amazon or many other places.

New Power Panel, an expensive lesson in pest control

Other openings can be filled with a combination of pot scrubbers and spray foam. Using spray foam alone often does not work, as the mice will crew through it.

I also keep a can or two of bee spray at most sites. Bees, hornets and paper wasps love to make nests in propane tank fill covers, ATU’s, under air conditioning units or anyplace else that is sheltered from rain.

Incandescent Indicating lamps

What is wrong with this picture?

WBNR equipment rack
WBNR equipment rack

It is a little bit blurry, but the real problem is that none of the indicator lamps on the phasor or antenna monitor are working.  Those little incandescent 387 bulbs burn out frequently.  It is difficult to tell, at a glance, whether the phasor is in daytime or night time mode.  One also cannot tell which tower or mode is selected on the antenna monitor.

It is a small job to replace them, but it does take some time.  They currently exist in older transmitters, studio consoles, meter back lighting, and other control indicators.  Since I began working in radio, I have replaced hundreds of these little lamps.  I would rather spend my time on more interesting projects.

The 387 bulbs cost about a dollar each and last less than a year, in most cases.  Fortunately, there is a solution to all this.  Enter the based LED replacement lamp.  These little guys have the long life of an LED (100,000+ hours) in a package that is a direct replacement for the Incandescent lamp.  They run about $5.31 each.

Dialight makes a very handy cross reference:

Dialight Incandescent to LED cross reference
Dialight Incandescent to LED cross reference

The entire cross reference section is three pages long and is a part of their PMI catalog.  The full cross reference .pdf can be found here.

Those Dialight LED lamps are available from Mouser, Allied and Newark Electronics.

Time is money.  There are much better things to be doing than going around replacing incandescent indicator bulbs in various pieces of equipment.  At the same time, it is important to know what the status of that equipment is at a glance, which is the reason for using any type of indicator in the first place.  Using drop in replacement LED indicating lamps with certainly save time and money in the long run.

Something is not right

The Goddamnitnotagain edition:

PA module with burned open output transformer

I went to do maintenance at one of our sites and noticed that a certain transmitter was running at half power. Followed the path of the fault log and found this. When I mentioned it to the station staff, they said, “Yeah, we noticed it sounded a little funny…”

This is the second time this has happened with this particular transmitter. In any case, this is what I get paid for, so I am certainly not complaining. If only every problem where this easy to find.

When I get back out there to replace this, I will bring out my network analyzer and sweep the antenna and transmission line to make sure there are not issues with that. In addition, I will double check all the grounding to make sure the copper thieves have not made off with any critical components like the ground buss bar or #2 solid down lead wires.

GatesAir FLX-40 one year in

I was at the WEBE transmitter site recently and took the time to look over transmitter we installed last year:

GatesAir FLX-40 transmitter, WEBE Bridgeport, CT
GatesAir FLX-40 transmitter, WEBE Bridgeport, CT

Overall, I would say that this transmitter has been very reliable.  We had to install a UPS for the exciter and HD Radio exporter, but that is not a big deal. During the first power outage, the exciter went dark first. It took longer for the transmitter controller board to lose power, in the interim the controller turned the transmitter power all the way up. When the generator came on line 10 seconds later, the transmitter returned to operation at 41.5 KW. This, in turn, caused one of the other field engineers to freak out and nearly lose his mind (stay away from the brown acid, FYI).

I installed the UPS a few days later.

WEBE TPO 35.3 KW with HD Radio carriers on
WEBE TPO 35.3 KW with HD Radio carriers on

Transmitter power output is 35.3 KW, which is getting into the semi-serious range. The reflected power goes up when it gets warm out and goes down in colder weather.  Over the winter, it was running about 50 watts.  Even at 138 watts, that represents 0.004% reflected power. The TPO forward goes to the 6 bay, 1/2 wave spaced antenna side mounted, 470 feet (143 meters) AGL. The station covers pretty well.

WEBE Pump station
WEBE Pump station, pump is running 2/3 speed and fans are running at about 1/2 speed

Overall, I would give the liquid cooling system an A grade. The transmitter still dumps a fair amount of heat into the room from the RF combiners and PA power supplies. Most of the heat, however, ends up outdoors. Previously, we had two Bard 5 ton AC units running almost full time. Now, only one AC unit cycles on and off except for the hottest days of the year. Outside temperature when this picture was taken was 81 degrees F (27.2 C).

Next year, we will have to send a sample of the coolant off to be analyzed.

Gates FLX-40, WEBE Bridgeport, CT
Gates FLX-40, WEBE Bridgeport, CT

I have had good experiences with the GatesAir FLX/FAX series transmitters. I would recommend this to a friend.