Had to do some work at a transmitter site today and had to put the backup transmitter on the air for a few minutes.
These were good units in their day and many continue on. This transmitter was new in 1986 and served as the main transmitter until 2015 or so. This unit still has the tube driver (4CX250B) which tended to use a set of tubes every year or so. The PA tube normally lasted 4 years or so.
I miss the analog meters sometimes. There is something satisfying watching all the meters come up together when the plate on button is pushed.
Greetings from the Roxborough tower farm, a place with roots. It is slightly northwest of Philadelphia, PA, and is home to many TV and FM stations. The public road that cuts through the tower farm is called Domino Lane because if one tower falls, they all fall. A comforting thought to those that live in the vicinity I am sure.
The reason for the visit; this rather nice GatesAir FLX20 transmitter:
I must admit, I am growing rather fond of these transmitters. This unit is being installed because the station had to move from its old site, just down the hill. The tower owner is taking down the tower and building due to the age of the tower. Thus, it was moved into the KYW-TV building. If Wikipedia is to be believed, KYW-TV is the oldest TV station in Philadelphia, signing on in 1932.
The site is still being built as we were installing this transmitter. These days, the electricians are having supply chain problems like everyone else. There were delays getting the large electrical panel board and other necessary things for the build-out.
Overall, the installation went well. This system is using flexible hoses for the coolant loop. We have installed two of these liquid-cooled transmitters with 1 1/2 copper pipe. These days, copper pipe is expensive, so most are opting for flexible hose installation.
Topping off the pump station after 50/50 fillup. After the initial system fillup, it takes a while for all of the dissolved air to come out of the Heat Transfer Fluid (HTF). The extra steps with a liquid-cooled system are worth it, especially if the station is running HD. With the HD carrier on, the transmitter efficiency is 54% AC to RF. With a TPO of around 15 KW, that is a whole lot of heat that needs to be dissipated during operation. It is much cheaper to pipe the heat outside to a heat exchanger than to use several tons of AC to remove it from the room.
I am reminded of a Pink Floyd compilation album from the very early 70s. The music dates back to the late 60s and Syd Barrett. Poor Syd; shine on you crazy diamond!
I recently finished installing these rather nice GatesAir FLX-40 transmitters:
Audacy New York decided to move 94.7 from the East Orange, NJ location down to the WOR transmitter site in Rutherford, NJ. Acting as contractors for GatesAir, we installed these two transmitters. I can say, I like the liquid-cooled transmitters for several reasons. First, once installed, they seem to be very stable. I believe that the cooling scheme helps prolong the life of the RF devices by keeping the junctions at a constant temperature. Those semi-conductor junctions are tiny for the amount of current that they need to handle. Second, they cost less in the long run to operate. Anytime a refrigerant cycle can be skipped, that reduces or greatly reduces the electrical use. The Heat Exchangers in this system use VFD’s for fan motor control. That means more constant control over the HTF temperature and reduced electrical use on the fan motors themselves.
The pump stations have backup pumps as well. In the newer transmitter firmware, the pump control needs to be set up to automatically failover to the standby unit. It is a couple of clicks in the GUI to do this.
We didn’t have anything to do with the antenna installation, however, it is a good-looking antenna! ERI 4 bay 3 around mounted on one of the WOR towers.
Overall, this was a good project. Lots of moving parts during the installation, but we were flexible working with the client and other contractors and sub-contractors on site.
I regret not having enough time for writing these days. There are a number of reasons for this. Firstly, much of what I do running my business is mundane and not worth noting. For example; today I am going over work reports and reconciling the bank account. Necessary, but about as exciting as watching the grass grow or reading about drying paint.
However, the rest of the time I have been working on various projects around the northeast, to wit:
In Boston, I took part in converting an LPTV station to ATSC 3.0. That was interesting and I am enjoying the TV work.
In Syracuse, we had to lower a TV transmitter from the 23rd floor to the 22nd floor on the outside of the building. The transmitter itself became marooned because an electrical conduit for an alarm system was installed restricting the size of the stairwell.
Fortunately, we hired a moving company to do this. I am pretty sure that our insurance does not cover damages from transmitters falling 22 stories.
In NYC, I installed two FLX-40 transmitters for GatesAir.
In Kingston, NY a used BE AM1A (along with a coax switch and dummy load) was installed at WKNY.
It is nice that this station has a decent backup transmitter to buttress the aging, yet very reliable Nautel ND-1.
Even though it is a short drive away, I had never visited the 1969 Woodstock Music and Art Fair site in Bethel, NY. It was interesting and being sort of an audiophile, I enjoyed this exhibit in particular:
From the display:
This speaker stack sat on scaffolding high in the air… festival sound engineer Bill Hanley custom-built eight speaker cabinets for Woodstock, amplifying music and stage announcements across the large festival site… Afterward, the design would be known in the industry as the “Woodstock Bin.”
Bethal Woods Performing Arts center Museum, August 10, 2022
The high-frequency horns used Electrovoice diaphragm S/A compression drivers. I don’t know which driver was used for the bins.
I am also writing articles for Radio Guide, I hope that you are enjoying them!