Tales of disaster – Page 12 – Engineering Radio

The Devil is in the details

Sometimes it is the seemly small insignificant detail that will take a station off the air. To expound on that a bit, I have my own story which happened yesterday. The back story is this: About three years ago, some unauthorized tower climbers climbed the WICC south tower all the way to the top. The station remained on the air at full power while this was going on. Once at the top of the three hundred-foot tower, the climber, we can call him “Crack Head,” managed to loosen, then remove the beacon and throw it to the ground. Mind you, this guy had no safety climbing equipment whatsoever and he had to stand on the top plate, which is all 20″ x 20″ square, of which the beacon takes up 16 inches. A two-inch purchase between himself and eternity demonstrates that God does indeed smile on fools and drunks.

WICC south tower with long island sound in background — WICC South tower with Long Island sound in the background

Fortunately, his friend on the ground had a video camera and filmed the entire episode. Even better, they then posted it on Youtube. The police took interest in this video and its owners because the damage to the radio station was significant, and with the tower being about a mile away from the end of the Stratford Airport runway 17, presented a real hazard to air navigation. Needless to say, the video was used by the prosecution and both crackheads are now in prison, God having limits after all.

A spare beacon was hoisted to the top of the tower and placed in service. This beacon was quite old and leaky and continually failed, burning out the tower light flasher. Thus, it was time to replace it. We took advantage of the outstanding weather and the crew from Northeast Towers made quick work of it. Removing and lowering the old beacon to the ground, then hoisting the new beacon up and installing it. I goobered it by not taking pictures of the beacon fixtures flying up and down the tower. I took the station off the air for about five minutes to check the condition of the wiring going up the tower, making sure there were no shorts up the tower or back toward the transmitter building. While I was doing this, I overheard the two-way radio conversation between the tower climber and the ground crew on wiring. It seems the old beacon had only two wires, hot and neutral. The new beacon had three wires, hot, neutral, and ground. Tie the neutral and ground wires together, instructed the tower boss.

Nothing more was thought of that, it sounded okay to me. Unfortunately, the tower had other ideas. About an hour after we secured from the job and drove away, the station went off the air. It seems the neutral wire was not referenced to the tower previously. Because now the neutral wire was tied to the top of the tower, the RF found a path to the ground via the tower lighting choke at the base of the tower. It started arcing to its access door causing the transmitter to go off around 4 PM. Equally unfortunate was the fact that the construction gate was closed and I had to get a boat ride with the harbor master, which took about an hour to arrange. The entire situation was further complicated by darkness, which comes predictably around 6:30 PM this time of year.

When I arrived back out at the base of the tower, I took the metal access door off of the tower light choke cabinet. I could see the fresh track marks all across the bottom of the door. With the door off, I turned the transmitter on. Worked just fine. I tried cleaning it off with a Scotch Bright, but to no avail, the transmitter would not run at any power level with the door in place.

Finally, the harbor master becoming impatient and darkness quickly falling, I taped a garbage bag over the tower light choke box with the door off and turned the transmitter back on. The tower crew will have to come back and remove the ground wire on the beacon.

The first rule of troubleshooting: Check the last thing that was worked on first.

Update: And look, here is the original story in Radio World: Tough times a Pleasure Beach.

The surreal trip to the WICC transmitter site

What could be so bad about going to an AM transmitter site on a peninsula off of the Long Island Sound. Sounds pretty nice, right? It began just so, driving through the town of Stratford Beach parking lot to the construction gate, the towers were visible off in the distance. A nice crushed gravel road across the barrier island, I have certainly been to worse places.

WICC towers pleasure beach island — WICC towers Pleasure Beach Island, CT

And then, things begin to look a little bit different. It is really hard to put into words, seems like some other country.

Pleasure Beach Bungalows — The beginning of the Pleasure Beach Bungalow Colony

It turns out this is not quite a nice trip after all.

Pleasure beach lawless zone — Pleasure Beach Lawless Zone

I’ve been to several so-called “developing areas” like Port Au Prince, Hatti for example. Nothing ever looked this bad.

Pleasure Beach ocean side bungalow — Pleasure Beach Ocean Side Bungalow

I can imagine some family coming here every summer to spend time at the beach.

What anarchy looks like.

Pleasure beach burned out cottage — Pleasure Beach burned out cottage

The back story is this: From the 1920s until 1996, Pleasure Beach was a nice seasonal oceanside bungalow colony, complete with an amusement park. These cottages (but not the land they were on) were owned by people from the surrounding cities and towns and the entire area appeared to be quite nice in its day. Then, in 1996, the wooden bridge that connected Pleasure Beach to Bridgeport burned. There are several theories; crackheads, radical environmentalists, etc. The city of Bridgeport did not rebuild the bridge, which meant the only access was by walking from the Town of Stratford beach parking lot, a trek of at least a mile or longer. In 2007, the town of Stratford decided not to renew these land leases, and the building owners were forced to remove any remaining items they wanted by barge. Soon thereafter vandals began walking down the peninsula from Stratford. Slowly, most of the bungalows were broken into and several were burned. This is mostly the work of “kids,” who, because they are under the age of 18, get a slap on the wrist and returned to their parents. Oh, those wacky kids, what will they do next?

Truth be told, they should be the ones out here cleaning this up, for free.

Finally, this year, the city began tearing down and cleaning up the remaining buildings, trying to put the former bungalow colony “back to nature.”

The transmitter site for WICC moved here in 1932. This building contained a nighttime operating studio, kitchen, bathroom, and bedroom. I can imagine hanging out here some summer night, spinning tunes, and having a good time. The former amusement part is just out of the picture to the left. At the amusement park, there was a carousel, a big snack bar, a dance hall, and an area for portable rides like Ferris Wheels and such.

Now the building is full of disused gear, old carts, transmitter, and tower parts, the water has been shut off and I’d not want to be out here at night under any circumstances.

The antenna array consists of two 300-foot Milliken towers, originally installed at WNAC (Now WRKO) Boston, MA. They were moved to Pleasure Beach Island in 1932. Many people mistakenly think these are Blaw-Knox towers. Milliken preceded Blaw-Knox by several years. They built and designed towers around the world for radio and electric transmission. In the late 1930’s they were bought out by Blaw-Knox, which kept the design. I love these tapered self-supporters, they have survived several major Hurricanes since 1932. The south tower is about 150 yards from the Long Island Sound. Salt air seems to do them no harm, either.

WICC Milliken tower, south looking up — WICC Milliken south Tower, looking up

The station operates at 1 KW day, 500 watts night, DA2. The towers are 60 degrees tall, spaced 149 degrees. That is a little short, however, they are surrounded by salt water, so the signal goes like gangbusters. Because they are short, the impedances are low, about 10 ohms for nighttime and 30 ohms for daytime. Since the towers are so wide, the impedances are flat far beyond 50 kHz on either side of the carrier, which makes it a nice broad-banded antenna system. The 1932 phasors and ATUs were redone in 1972. All of the common point impedance measurements are still posted on the wall.

WICC Harris SX-1A, Phasor and Harris BC1H — WICC Harris SX-1A, Phasor and Harris HC1H

The main transmitter is a 1990 Harris model SX-1A. It seems to be reliable enough, my experience with the SX-1 is it has an overly complicated control system. The backup is a Harris BC1H, a sort of hybrid solid-state tube unit, which is also reliable.

Frequency voltage meter — WICC frequency and voltage meter

This high-tech test and measurement center is attached to the incoming electrical service. Over the years, there have been some quality control issues with the incoming electrical service, mostly due to Osprey building nests on the crossarms. During rain storms, these nests catch on fire and kill the power to the site. The power company is in the process of redoing the electrical service to the building.

This is a video of the former amusement park and cottages shot two years ago when the cottages were more or less intact. It is a bunch of stills set to Pink Floyd music:

Looks like they all just got up and left.

Harris FM25-K

Old blue, I like to call them, the Harris 1980s model transmitters with black faces, white cabinets, and blue trim. I have yet to find one that I really like, the FM 25-K is, well okay. Sort of like that 200,000-mile jeep that works, most of the time, and it’s paid for.
This particular FM-25K transmitter is located at WIZN in Charlotte, VT.

This transmitter was new in 1987. It had a bad day yesterday, deciding to throw a temper tantrum and trip the HV power supply breaker. Fortunately, the station has a backup transmitter. When we arrived, we found the HV power supply feed through the insulator at E1 arced over and broken. Again, fortunately, this station’s management believes in stocking spare parts and a replacement was on hand.

Harris FM25K HV power supply feed through insulator

This is part of the RF filter for the HV power supply. This happened once before, about two months ago. The replacement insulator then was used, so that might be a factor. Two months ago, both capacitors in the Pi filter and the HV power supply cable (RG-8 coax) were replaced all the way back to the rectifier stacks.

The FM25-K can produce spontaneous high-frequency oscillations if not tuned properly. We looked at the transmitter output with a Rode Schwartz spectrum analyzer and found it to be clean. Exactly why it blew out another feed-through insulator is a bit of a mystery. Since the first replacement was a used part, we surmise that it may have been cracked. If this replacement insulator arcs, there needs to be a full investigation.

As I said in the beginning, I have found these transmitters to be okay, not the best, not the worst. Most of the problems I have encountered with the K series FM transmitters had to do with the controller cards. There are two, one analog and one digital. That’s what Harris calls them anyway. Like the SX transmitter, and the MW transmitter to a certain extent, the control circuits are way over complicated and full of +/- 5 volt CMOS logic. Having that type of control logic connected to a radio tower (e.g. lightning rod) is asking for trouble.

The sad story of WCVR

I have been the road warrior lately if you haven’t noticed a certain decline in the blog posts… One place that seems to keep pulling me back is Randolph, VT, which is about as close to the geographical center of Vermont as one can get and still be on a roadway. There resides the silent FM station formerly known as WCVR, to be returned to the air as WXVR by Vermont Public Radio.

WCVR went on the air in 1982 and was a community-oriented country station for 17 years. Then in 1999, it was sold to Clear Channel and things began to go downhill. Over the next decade, the station transferred ownership four times. Finally ending up with absentee landlord Vox Radio. By the time the station was sold to Vermont Public Radio last May, the years of neglect were compounded and the main transmitter was no longer running. The transmitter site was raided before the transfer and things like spare parts, a backup transmitter, and a dummy load were removed. As one engineer from VPR noted, the only thing of any value is the Shively antenna.

This story probably repeats itself a thousand times throughout the country as a small market, formerly community radio stations are left to die on the vine by big-time corporate radio gurus in Atlanta, San Antonio, and Las Vegas.

Said station has a McMartin BF5-K transmitter that is not currently running and by the accumulations of dirt, debris, and other evidence, has not run in quite some time.

The beauty of a McMartin FM transmitter is it is a grounded grid. Can’t get much simpler than that when it comes to FM transmitters. The downside is, of course, McMartin has been out of business for almost thirty years. Thankfully, Goodrich Enterprises is still around and still supports them.

The first order of business was cleaning out the filthy, and I mean absolutely filthy building. Several hours with a broom, dustpan, and shop vac got rid of most of the dirt and made my skin less likely to crawl. Then came the fateful attempt to run the transmitter. Loud arcs, power supply hum, and dimming lights revealed that all was not well. All of the fluorescent lights were out, new bulbs did not fix the problem. So, to the Grainger to pick up new fixtures and install them. Now, at least, we could see what were doing.

Next, step-by-step troubleshooting of the High Voltage power supply. Step one, resistance checks on the HV transformer and filter chokes to the ground. Next forward and reverse resistance checks on the rectifier stacks. All of those looked good. Next, we isolated the HV transformer and the rectifiers and turned the transmitter on; no problems. Next, we added the metering and filtering capacitors and turned the transmitter on; no problem. Finally, we found the problem with the HV power supply RF filter on the side of the PA enclosure. In a McMartin FM transmitter, there is a little box mounted on the outside of the PA enclosure that holds half the parts in this circuit. Taking that box off revealed a bad 200 pf 7.5 KV doorknob capacitor that was shorting to ground. Lots of arc marks, soot, debris, and other stuff make me think that this problem had been going on for a long time. I can kick myself for not taking a picture.

Hopefully, this thing will run for a few months while a replacement is sought.

Compounding that issue is the leaking transmission line connector at the bottom of the antenna, which was fixed, but there appears to be another leak somewhere else as the line still does not hold pressure for very long.

VPR is going to broadcast their Classical Music format on this station, starting as soon as we can make the transmitter run.

UPDATE: Pictures:

300 foot WCVR tower, Randolph Center, VT

Transmitter building:

WCVR Mc Martin BF-5K transmitter:

Arcing power supply filter section, the bad door knob capacitor has been replaced, still evident are the arc marks on the PA cavity:

Mc Martin BF-5K transmitter on the air:

We’ll see how long that lasts.