Damaged in last year’s F1 tornado, this thirty-foot Rohn 25-G tower needed to be removed from the roof. It actually went faster than I thought it would, the worst part being moving the 4-foot tower sections down to the salvage truck via elevator. Naturally, the day we choose to do this is the same day that one of the two elevators servicing the seventh floor is out of order.
Damaged Rohn 25G STL tower on the roof of the studio
This was the same tornado that picked up a twenty-ton rooftop air conditioner and deposited it in the parking lot. Luck would have it that no one was killed or injured.
Rohn 25G buckled tower section
Using a circular saw with a metal blade, a sawsall and a hand grinder, the tower was cut up into four foot sections. The sections, brackets, and tower base were taken to the scrap yard and disposed of.
Tower and transmission lines ready to be removed from the roof
There were several lengths of unused 7/8 inch foam coax, broken antennas, RG-59- RG-58, RG-6, rotor cable, etc that we cleaned off of the roof and tower.
The after picture
A good little project to have completed.
The studio build-out for WEBE is also nearly done. August will mark one year of our company’s involvement at WICC/WEBE. I was looking around today and comparing the difference between when we started to now. Many things have been done.
Received a call last night, after a particularly bad thunderstorm, that WGHQ in Kingston, NY was off the air. Earlier in the day, the transmitter had tripped the main breaker after a thunderstorm. I arrived at the transmitter site and found the breaker tripped again. Once the breaker was reset, the transmitter came back on and ran without any overload indications. The transmitter is a 10-year-old Nautel ND-5.
WGHQ Nautel ND-5 transmitter
I was thinking of breaker fatigue as the breaker is the original 1960 breaker installed when the building was built. I reset the breaker and turned the power output down to 3 KW, thinking the reduced load might not trip the breaker until we could get a replacement. The transmitter was on the air running as I was about to lock up and go home when I heard, but more felt through the floor, a THUMP! There I stood and watched the transmitter go dark.
At least it happened when I was there looking at it. Because of the lightning, I was thinking of something in the output network. I reset the breaker and once again, no faults, and the transmitter came back on. Strange. Obviously some sort of power supply issue. Here are the clues:
The B- voltage was right where it should be at 72 volts.
All other readings, reflected power, forward power, and power supply current are normal before and after the breaker trip
No fault lights
The service panel breaker, which was tripping, is rated for 70 amps, and the transmitter front panel breaker which did not trip, is 50 amps.
The Nautel factory rep was thinking either breaker fatigue or the big transformer in the base of the transmitter had gone bad. According to him, no one had ever heard of a transformer going bad in these transmitters, which makes a certain amount of sense. Unlike a tube transmitter, which steps the B+ voltage up several times, these transmitters reduce the B- voltage by about 2/3rds or so. With a step-up situation, a surge would be multiplied many times and could very easily punch a hole in the transformer’s secondary winding insulation. I have, in fact, experienced this on at least two occasions.
That leaves the wiring between the transmitter and the service panel. I double-checked the panel breaker with my volt meter to ensure that the voltage was indeed off. Then I removed each phase from the connection lugs in the transmitter and tested the wire to ground with my Fluke 77 DVM. Sure enough, two of the phases showed resistance of 1.2 and 1.7 MΩ to ground where it should have been infinite. Further, when I took the cover off of the service panel, I found a dead mouse. Unfortunately, I didn’t have any #4 THHN, and all the home improvement stores were closed by that time, so it had to wait until morning.
The thunderstorm seems to be a coincidence.
After we pulled the wire out of the conduit, we found this:
Mouse chewed feces encrusted electrical cable
It is a little hard to see, but that shiny spot is copper. The cable jacket is chewed back quite a ways and the entire thing is encrusted in mouse feces and urine. I love to work on stuff like this. LOVE IT! Hantavirus, here we come! That reminds me, I need to get some of those blue latex exam gloves and throw them in the truck… Anyway, far back in the conduit running through the concrete floor where it bends to go up to the service panel, the mice apparently had a nest. They got into the conduit under the transmitter, where it transitioned from 3-inch rigid to 1 1/4-inch flexible metal without the benefit of a junction box or proper fitting.
We pulled new copper conductors in and installed a proper junction/transition between the 3-inch and 1 1/4-inch conduit. The service panel was also missing several knockouts of various sizes, which were sealed with knockout seals. The transmitter was back on the air at full power about 16 hours after it went off. Unfortunately, the station has no back up transmitter, so they were off for that period of time. Perhaps now they will look into a backup transmitter or at least an exterminator, but probably not.
If one considers paradise an FM35A. Going through another iteration of blown transmitter fuses for WEBE, Bridgeport, CT. Yesterday, I spent the afternoon examining the transmitter and found several interesting things:
Fresh arc tracks on the PA cavity and PA loading capacitor
The shoes and bars in the high-voltage contactor were severely pitted
One of the mains phases (middle) in the high voltage supply appears to be heating up, likely due to a loose connection.
Discolored wire on buss bar
I checked and re-tightened all of the mains connections. Apparently, this is an old problem, as the Allen screw was tight. Interestingly, the fuse that was blown was on the red phase, which is different from what it was last time.
I spent the afternoon filing and sanding off the arc track marks in the PA cavity. It is very important to file flat all sharp points that were the result of arcing. Any sharp points will induce corona. I also filed down all of the contacts in a high voltage contactor, which took a fair amount of time. These are soft copper shoes and bars that had so much pitting and carbon I wonder how they didn’t catch on fire. I filed them flat. We were back on the 35A transmitter at full power by 4:30 pm.
If this happens again, I will bring my megger out and check the insulation on the wire between the disconnect switch and the HV power supply.
When I left the site at 5:30, I felt like we did some good work.
We have received somewhere between 5-6 inches of rain in the last four days. That, coupled with the deep snowpack and the still-frozen ground has led to some flooding. The WLNA antenna array is located along the Peekskill Hollow Creek in northern Westchester County, NY. Back in 1980, it might have seemed like a good idea to locate an AM station in a tidal swamp along the Hudson River. I am sure the land was not that expensive and from an engineering standpoint, having a continually wet, partially brackish ground system may have seemed like a slam dunk.
Unfortunately, the idea never really panned out in the application. First of all, the neighbors had other ideas, fighting the radio station owners all the way to the NY State Supreme Court. Secondly, technically, it never lived up to expectations. The original non-directional antenna on 1430 was a 1/2 wave tower which by all accounts, worked very well. It did not, however, allow for nighttime service, which is why the new sight and array were sought. By the time the system was built, AM was already in steep decline and I doubt the owners ever recouped their investment.
Fast forward to today. All five base insulators are under water and the transmitter is off the air. These are pictures from last Wednesday after the first flood waters receded from the Monday/Tuesday storm. I imagine it looks worse this morning, although I don’t own a boat and won’t be wading out there to look.
Base insulator, tower 2 WLNA array, Peekskill, NY
This is tower two of the daytime antenna array. Clearly, it spent some time underwater. We cleaned off all the debris from all the tower bases. A far worse prospect is the ATU’s:
WLNA tower 1 ATU, Peekskill, NY
This is the Antenna Tuning Unit for tower 1, which is the reference tower for both the day and night arrays. The E.F. Johnson contactor in the bottom of the cabinet was fully submerged for an undetermined amount of time. The bottom of the unit is covered in fine silt. The high water mark is visible on the right side of the aluminum cabinet.
The contactor is going to need to be replaced, or at least rebuilt. The ATU cabinet will need to be washed out. There are two other ATUs that suffered the same fate.
WLNA antenna array, towers 3 and 5
This is the end of the catwalk next to the Peekskill Hollow Creek looking west towards the Hudson River. The water level reached the bottom of the catwalks and had receded about 4 feet when this picture was taken.
WLNA antenna array, tower 5, Peekskill, NY
Lookup east, upstream at tower 5.
WLNA antenna array looking north, Peekskill, NY
This is the antenna array looking north, with my back facing the creek. Tower one is the center tower, tower two is on the right and tower four is on the left. The daytime array consists of towers 1, 2, and 3 bearing 300 degrees. The night time array consists of towers 1, 4, and 5 bearing 335 degrees, so the array makes a big X in the swamp. More from the FCC database.
It is going to take a lot of work to clean out all these ATUs and repair the damage. Clean water is at least 1000 feet away. My question is; why bother? Once upon a time, this station was viable, well thought of in the community, etc. Now, I doubt anyone knows it is off the air. The current ownership over the last thirteen years did, what I’d like to call, a controlled flight into the ground. Axing staff, cutting maintenance, and generally neglecting the station. Why not take it dark for a while and figure out what to do with it? Likely somebody would buy it, even if for the land it sits on. Anyway, the grind continues…
