The inglorious task of AM antenna array maintenance

AM radio stations are rough customers. They frequently operate on the margins, both in terms of ratings and revenue. Their transmitter plants are complex and very often have been on a reduced maintenance schedule for years, sometimes decades.  Those of us that understand the operation of AM transmitter plants and all their quirky behaviors are getting older.  I myself, feel less inclined to drop everything and run off to the AM transmitter site when things go awry.  Seldom are such efforts rewarded, much less acknowledged.  Station owners are also finding that their previous demands are unrealistic.  For example, time was that any work that takes the station off the air had to be done after midnight.  These days, I can tell you, I will not be working at your radio station after midnight.  You can find somebody else to do that work.

Thus, today, we took this particular AM station off the air from Noon until 3 pm to diagnose and repair a problem with the four-tower daytime array.  Once again, this involved a shift in common point impedance and a drastic change in one tower’s current ratios.

Antenna Tuning Unit, mice have made a mess
Antenna Tuning Unit, mice have made a mess

In all fairness to the current owner, this ATU reflects years of neglect. At some point, mice made a home in there and created a mess. The ATU smells of mouse shit, piss, and mothballs.  It is full of mouse droppings, grass seeds, and fur.  All of the ATUs in this array are in similar condition.

Paper wasp, inside ATU
Paper wasp, inside ATU

It was warm enough that the wasps were active, if not a little bit lethargic.

Broken stand off insulators in ATU
Broken stand-off insulators in ATU

This coil is being held up by the tubing that connects it to other components. When the ATU was built, no nylon or cork bushings were used between the insulators and the wall of the ATU they were mounted on. Heat cycling eventually did all of the insulators in.

Catwalk to the other towers
Catwalk to the other towers

Catwalks to the other towers. At least the swamp grass has been cut this year, it is only four feet tall instead of ten.

Tower base
Tower base

The tower bases are all elevated above the theoretical maximum water level. The ATUs are also up on stands with platforms build for maintenance access.

ATU Work "platform"
ATU Work “platform”

I cannot even blame the current owner, who has to spend considerable money to make repairs and upgrades to this site. It is very difficult and very expensive to catch up with deferred maintenance. Sadly, most AM stations we encounter have similar or worse problems.

I think it is too late to save many of these AM stations.  The technical issues, lack of revenue, perceived poor quality, and lack of good programming are all taking their toll.  At this point, the hole is so deep there is no hope of ever getting out.  The FCC’s faux interest in “revitalization” followed by two years of stony indifference seems to be a final, cruel joke.

The old school marketing campaign

I found these old drawings in the filing cabinet and thought they were kind of cool. They look like they were drawn sometime in the 50s for the WPTR studio at 1860 Central Avenue in the Town of Colonie.

WPTR-billboard

It looks like there was a lot of Neon, including a speller, which I take to mean the sign would spell “W-P-T-R 1540” and then turn off again.

This was the sign for the entrance to the studio building

WPTR sign for front of old studio building at 1860 Central Avenue
WPTR sign for the front of old studio building at 1860 Central Avenue

I think this is a take-off on the old KHJ sign in Los Angeles.

Something fun

So, I spent wasted several hours on this SDR website over the holiday weekend:

University of Twente SDR website
University of Twente SDR website

This is a web-based SDR hosted by the University of Twente in Enschede, Netherlands. I enjoyed listening to the European medium-wave and short-wave stations available.  Something that is always fun to check out: UVB-76 on 4625 KHz.

Have fun!

PS: A special thanks to all those who have donated to the cause via the donate button on the upper right sidebar.  I had enough money to buy a FUNcube dongle SDR.  I think I have all the other necessary hardware to launch one of these sites myself.  If or when that happens, I will post a link here.

Accidents, mistakes, mishaps and other tales

Let’s get started:

Results of a deer vs automobile accident
Results of a deer vs automobile accident

It does not look like much, however, that is about $5,500.00 worth of damage. What you don’t see is the mashed oil cooler and radiator. This happened on my way from one place to another during the early morning hours. I was traveling at about 55 MPH when a deer bolted from the woods and entered the roadway from the right. I did not have time to a break.

In a ditch
In a ditch

A momentary lapse of attention causes a loss of $80.00. I think I was adjusting the defroster as I was driving down the road when suddenly, I felt the car tilt over to an alarming degree. You can see the tow truck getting ready to pull it out. Fortunately, there was no damage to the vehicle.

Troubles with the neighbor
Troubles with the neighbor

This is on the access road to one of our transmitter sites. The station has a legal right of way through this property, however, the neighbor seems to object. I spoke with him and showed him a copy of our deed, he has since changed plans.

One side of a balanced audio connection disconnected
One side of a balanced audio connection disconnected

This is the downside of using category cable to make audio connections. The wires are not as rugged as say Belden 8451. This was causing problems because it is at an AM studio/transmitter site.

Burned 30 amp three phase contactor
Burned 30 amp three-phase contactor

Three-phase, 30 amp, 240-volt contactor installed in a 480-volt system. Lasted a few years, anyway.

White face hornets nest
White face hornet’s nest

New tenants on one of our towers. This is a white-faced (or bald-faced) hornet’s nest. They are really paper wasps, but that difference aside, these beasts are nasty, aggressive, and have a painful sting. Normally, I am a live-and-let-live kind of person, but in this case, they gotta go.

Dummy load attached to plywood
Dummy load attached to plywood

This is at one of our AM client’s site. Somebody, quite some time ago it seems, made this test load for a 1 KW AM transmitter. It is very nice, with carbon ceramic resistors, 50 ohms, and surprisingly little reactance. Then they attached it to this piece of plywood. As one can surmise, the load gets quite hot under full power and full modulation conditions. We remounted this in a cage-type enclosure and bolted it to the cinder block wall.

Scala PR-950U cross polarized
Scala PR-950U cross-polarized

The client at this station is complaining of intermittent STL dropouts and low signal strength at the receiving end. Found this Scala PR-950U antenna mounted for vertical polarization, but the antenna element is horizontally mounted. We’ll call it “vorizontal.”

Ribbon cable from a Cummins 135 KW generator
Ribbon cable from a Cummins 135 KW generator

This was discovered during routine maintenance and thankfully not during a power outage. Mice got into the control box of a newish Cummins 135 KW generator and chewed through what looked like a data buss cable. The generator would not run and the cable and control board needed to be replaced.

Bulging capacitors
Bulging capacitors

There are more bulging capacitors removed from flat panel monitors.

And so on…