The GatesAir FLX-40 transmitter is my first liquid cooled transmitter installation. Previously, I have installed an air cooled Nautel NV-40, a V-40 and a couple of BE FM-35T/20T units. The WEBE transmitter site in Bridgeport, Connecticut is an interesting facility.
This coal fired power plant smoke stack which currently holds up the six bay, half wave spaced Shively antenna. The old BE FM35A transmitters are getting little bit long in the tooth. Thus, we picked one to scrap, the other will be kept for backup service.
We saved a whole bunch of parts to keep the other FM35A on the air in backup service.
The power supply cabinet with that 500 pound plate transformer was the last to go.
The FLX-40 came on a large truck. Fortunately, we were able to open the side gate at the power plant and get the truck to the front door of the transmitter building easily. The transmitter consists of two large cabinets, each with two 10 kilowatt power blocks. There is also a pump station and an outdoor heat exchanger.
This transmitter design is based on the Harris digital TV transmitters.
The pump station and heat exchanger are the same systems used for TV transmitters. Liquid cooled units require a bit more planning on the installation end. The coolant piping should have a high spot from which everything else slopes down hill.
I put a 1/4 to 12 inch pitch on everything. Of course, there are several low points, the heat exchanger, pump station and bottom power blocks.
After assembling the cooling system, we pressure tested it for 24 hours.
Following that, we flushed the system with distilled water for several hours before we filled it with 40/60 glycol/water mix. Record low temperature in Bridgeport is -7 F (-22 C), thus a 40/60 mix will give protection down to -15 F (-26 C). The more water in the coolant, the better heat transfer capacity it has.
The pump station is controlled by the transmitter, which speeds up the pumps according to how much heat needs to be moved. In turn, the pump station control the fan speed on the heat exchanger outside.
The pump station runs with one motor most of the time. The other pump motor will run in the event of failure or if there is not enough flow through the power blocks. Each of the four power blocks has a flow rate meter on the return line.
Variable Frequency Drive (VFD) fan motor controllers show them running at half speed.
GatesAir 50 KW heat exchanger mounted on concrete pad behind the building. Air flows out from the motor side.
As with most things, some assembly required. The RF modules needed to be placed in the power blocks according to their serial numbers on the test data sheet. This insures that the information on the test data sheet matches the installed transmitter configuration. The power combiner between the two cabinets as well as the reject load and directional coupler all need to be installed.
RF modules with large aluminium heat spreaders. Coolant flows through each module.
On the air!
We ran the transmitter for several hours into the antenna yesterday afternoon. The coolant system is still purging air, so we periodically needed to add water/antifreeze to the pump station to keep the pressure between 12-18 PSI. Eventually, the TPO will be 34 KW with the HD carrier(s).
All in all, I would say that this was a fun project. The liquid cooled transmitter had a few extra steps during the installation process, but not too difficult.
I have been so busy that I forgot to post the pictures of the completed studio build out. Overall, I would say that I am pretty pleased with the end result. Of course, this is not Manhattan but rather an unrated market in central New York, and the budget reflected that. Overall, the radio stations are in much better technical condition than before. They are now located in the center of their community within walking distance of the town hall, other civic locations and activities.
There are five radio stations broadcasting from this new studio space. Two stations are simulcast using the Westwood One Classic hits format from the satellite. The only AM station is a Fox Sports Radio affiliate from the satellite with a local morning show. Another one is a “we play anything” computer juke box and final station has a country format with quite a bit of local content. Any station can go on the air from either studio. In addition, all stations can simulcast the mother ship from Oneonta, which comes down via a Barix Exstreamer 1000.
The Technical Operation Center consists of four racks containing the Ethernet routers, switches, a patch panel, automation systems, audio routing switchers, air monitor receivers, audio distribution amps, Barix units, Wheatstone Blade IP 88A STL, etc. The equipment racks came from a disused site in New Jersey.
The satellite dish and receivers are located at the transmitter site, audio and closures come back via the Wheatstone Blade IP 88A.
Everything in this room is backed up by a STACO 2.5 KVA UPS.
The wire termination from the studio are mounted to Krone LSA-PLUS blocks. Studio trunk wiring consists of connectorized 25 pair CAT 5 cable. There are also six runs of shielded CAT 5e cable for Ethernet and extended KVM from the TOC.
There is a manual transfer switch with a NEMA L14-30 input receptacle on the bottom. A twenty for 10/4 SOJ cable will reach the ground from the window in the left hand side of the picture. This is the standard NEMA plug/receptacle set for a moderate sized portable generator. That feeds a 100 Amp sub panel which in turn feeds the racks and studio equipment. Thus the entire facility can be run on a 5000 watt (good quality) portable generator in the event of a prolonged power outage.
The ground buss bar is connected to the main building ground at the service entrance. All racks and studio consoles are grounded to this main ground point.
The air monitor receivers feed both studios. There is also a provision to connect audio silence sensors up to each air monitor DA to notify the station staff in the event of an off air situation. Believe it or not, this type of system has never been installed for these stations.
Studio A is the main studio. The AudioArts Air4 console is a good fit for this type of operation. These consoles have USB outputs, so the console can act as a sound card for the digital editing computer. Each studio is equipped with an air monitor switch that can select any station to feed the external monitor input on the Air 4 console. This allows the guy on duty to keep an eye on all the signals coming from the facility.
The counter tops were custom made at a local kitchen place on trade. The microphone are Heil PR-22 with shock mounts, which are better than the Realistic mics in the old studio. This is the first time that the main studio has had more than one microphone. The morning show guy has already pressed those guest mics into service with a few on air interviews.
The monitor speakers are JBL LSR305 mounted on home made speaker stands consisting of 18 inch black iron pipe and floor flanges.
The small equipment rack is on casters and can roll out from under the studio furniture to get at the back of the equipment. A used Gentner DH3 TELCO hybrid is used to get phone callers on the air. Adobe Audition is used for editing and production on the left hand computer monitor. That CPU is in the bottom of the roll around rack.
The office chair and other furniture was also acquired on trade.
What the operator sees. STORQ computer on the left for music, Scotts SS32 on the right for automation. Both are extended from the TOC. Unless the morning show guy is live on the air, the console is bypassed and the audio stays in the TOC.
It all works pretty well.
Studio B is the same as Studio A except fewer microphones.
Studio B operator view. This studio can be used for one of the other stations or production.
Again, this is not a Fancy Nancy installation, but it does get the job done.
Alternate title: Winter in the Northeast
For all you southerners and west coast people, we have been having an average winter here in the Northeast. While many of our transmitter sites are drive ups, we have several located at ski area mountain peaks. Technically, those mountain top transmitter sites are a fantastic way to get the Height Above Average Terrain (HAAT) way up there. Logistically, they are much more difficult to deal with. Installing a new transmitter or even refueling a generator takes major effort. Working in the cold and wind is much more fatiguing and requires paying special attention protective clothing, hydration, exposure, etc.
Here are a few pictures from Killington and Pico mountain ski areas in Vermont
The snow grooming machine is the only way to bring anything up to the top of the mountain during the winter time. In this case, I needed to replace a BW Broadcast TX 1500 watt transmitter.
Even with the snow grooming machine, the last few hundred yards needs to be walked. Fortunately, the snow is packed and not too deep here.
Tower is encrusted with ice. I can tell the tower climber is having a great day:
Riding the chair lift back down the mountain gets plenty of strange looks from those skiers coming up:
Over on Killington Peak, conditions are actually worse.
The ERI antenna heaters cannot keep up with the ice buildup.
The general manager insists that this winter is not too bad and everything should be working right. My statement to her: Based on my 27 years experience, your shit is fucked up. But if you know how to fix this, come on up and show me. She deferred.
What the fire tower looked like last winter.