The GatesAir FLX-40 transmitter

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.

Smoke Stack, Bridgeport Energy, Bridgeport, CT
Smoke Stack, Bridgeport Energy, Bridgeport, CT

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.

Scraping 34 year old BE FM30A transmitter

We saved a whole bunch of parts to keep the other FM35A on the air in backup service.

BE FM30A power supply cabinet

The power supply cabinet with that 500 pound plate transformer was the last to go.

On second thought, that plate supply transformer is a good spare to have
On second thought, that plate supply transformer is a good spare to have

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.

FLX-40 cabinet two off the truck
FLX-40 cabinet two off the truck
FLX-40 cabinet one
FLX-40 cabinet one
FLX-40 in place, cabinets bolted together
FLX-40 in place, cabinets bolted together

This transmitter design is based on the Harris digital TV transmitters.

FLX-40 pump station
FLX-40 pump station

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.

Send and return coolant lines
Send and return coolant lines

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.

Holding steady at 18 PSI for 24 hours
Holding steady at 16 PSI for 24 hours

After assembling the cooling system, we pressure tested it for 24 hours.

Installation debris in the coolant line strainer
Installation debris in the coolant line strainer

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.

At the highest point in the system, there is a sight glass and an air purge valve
At the highest point in the system, there is a sight glass and an air purge valve

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.

FLX-40 pump station on line
FLX-40 pump station on line

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.

Heat Exchanger Fan motor controllers, Variable Frequency Drive modules
Heat Exchanger Fan motor controllers, Variable Frequency Drive modules

Variable Frequency Drive (VFD) fan motor controllers show them running at half speed.

50 KW heat exhanger
50 KW heat exhanger

GatesAir 50 KW heat exchanger mounted on concrete pad behind the building. Air flows out from the motor side.

One of several shipping containers with modules and other parts for the FLX-40
One of several shipping containers with modules and other parts for the FLX-40

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.

FLX-40 power amp module
FLX-40 power amp module
WEBE, Bridgeport, CT GatesAir FLX-40 on the air for the first time
WEBE, Bridgeport, CT GatesAir FLX-40 on the air for the first time

On the air!

FLX-40 into the antenna
FLX-40 into the antenna

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.

Studio Buildout, Part III

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.

Walton TOC

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.

TOC wire terminations

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.

Studio A

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.

Studio A

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.

Studio A

The office chair and other furniture was also acquired on trade.

Studio A

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

Studio B is the same as Studio A except fewer microphones.

Studio B

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.

Hoth

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

Your ride is here.
Your ride is here.

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.

Trail from ski lift to tower
Trail from ski lift to tower

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 on Pico Mountain
Tower on Pico Mountain

Tower is encrusted with ice. I can tell the tower climber is having a great day:

Tower climber working on ice encrusted towe
Tower climber working on ice encrusted tower

Riding the chair lift back down the mountain gets plenty of strange looks from those skiers coming up:

Pico chair lift
Pico chair lift

Over on Killington Peak, conditions are actually worse.

Killington Peak tower
Killington Peak tower

The ERI antenna heaters cannot keep up with the ice buildup.

ERI two bay antenna with ice.
ERI two bay antenna with ice.

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.

FM transmitter building and antenna
FM transmitter building and antenna

What the fire tower looked like last winter.

Killington peak fire tower
Killington peak fire tower
Train from the Gondola to the tower
Train from the Gondola to the tower