General – Page 12 – Engineering Radio

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

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.

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

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 in place, cabinets bolted together

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.

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

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

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.

Heat Exchanger Fan motor controllers, Variable Frequency Drive modules

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.

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.

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.

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 to 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 wintertime. 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 need 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:

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:

Over on Killington Peak, conditions are actually worse.

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 of 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.

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This information is from an occasional reader who wished to remain anonymous.

Another AM station surrenders its license, this time from north of the border. CKSL, London, Ontario, Canada is gone for good. The current owner, Bell Media, has determined that it would cost more to repair the deficiencies with the antenna system than economically feasible, especially considering its low ratings. Here is their filing with the CRTC:

Bell Media is the licensee of CKSL-AM 1410, assuming stewardship of the station in 2013 as part of the Astral Media acquisition.

A technical review of the transmitter site was recently completed both by Bell Media and contractors, which has resulted in the determination that the AM array poses an unacceptable risk from a health and safety perspective. The five towers are experiencing serious structural degradation and also require repairs to the aviation safety lighting system. In addition, the building which houses the transmitter has shifted off its foundation (as have several of the individual tower sheds).

Given these problems, Bell Media would need to make a significant financial investment to bring CKSL-AM’s transmitter up to compliance with Human Resources Development Canada, Industry Canada and NavCanada operational codes and standards, all of which is estimated to exceed $3 million dollars.

From a market perspective, CKSL-AM has consistently ranked last out of all ten commercial stations in the London market, both in audience share and revenue generation, over the last several years. In fact, since 2013 the London market has seen radio revenues drop 4% and CKSL-AM generates the least amount of revenue of the stations in the market. Even with a significant investment in programming, this trend is unlikely to be reversed.

In light of the significant capital costs coupled with the absence of revenue and audience share, Bell Media is respectfully requesting the revocation of the CKSL licence.

Well, 24/7 comedy will do that to you. Somebody in the business said to me recently “The listeners are abandoning radio!” No, it is the broadcast station owners who are abandoning their listeners and their cities of license. I have a news flash for all current broadcast station owners; as surprising and radical as this might sound, bland, boring, canned, completely irrelevant, dismal, uninformative, unimaginative, unentertaining, dreary, stale, unenjoyable programming will drive away even the most loyal listeners. People really want to listen to the radio, it is an easy habit and readily accessible. Radios are ubiquitous; they are in our kitchens, bedrooms, cars, hotel rooms, offices, restaurants, barber shops, etc. That, however, may not always be the case, as more and more people move to Spotify, Pandora, or Apple radio when they are tired of the disappointment. I was listening to a certain sports radio format the other day and I kept waiting for something interesting to happen. I waited and waited. I would say to myself; okay, this will be the segment when I will learn something or be entertained. This upcoming guest will say something interesting. Sadly, those expectations were never met and I will never tune into that station again. Elevator music would have been better. Worse than sports radio, 24/7 comedy is the absolute death knell. This is like saying; we are out of ideas and we do not care.

Here are a few pictures of the former CKSL-AM transmitter site:

CKSL_transmitter — CKSL transmitter building

CKSL_transmission — CKSL transmission line bridge

Actually does not look too bad, at least the field is mowed. I have seen much, much worse. Those bolt-together towers, though. I would bet that they are the real problem, bolts are deteriorating faster than the tower steel. Very likely all the towers need to be replaced and that is why the license is being surrendered.

If you are a radio geek, get out there and take some pictures of your favorite radio station. If the current trends continue, eventually they will all be gone.

Came as a stock item

So, I wore out another car and it was time to get a new one. Unexpectedly, the new car came with one of these fancy gizmos:

This is not the first HD radio I have owned, the Jeep Cherokee had one that I install myself. This is the first time it came with the car and I didn’t even mention it to the sales guy.

A few observations:

Many stations’ HD1 channels don’t sound very good, they are either shrill and tinny, or not synced with their analog counterpart.
There still aren’t very many stations transmitting HD Radio; FM stations are either NPR affiliates or belong to a few larger corporate owners. The AM stations are few and far between.
AM HD Radio still has numerous problems in the mobile listening environment.
Many of the HD 2/3 don’t sound very good; low audio levels, muffled modulation, low bit rate audio, etc. The only exception that I have found so far is Vermont Public Radio’s classical format, transmitted on the HD2 of WVPS, Burlington.
HD2/3 channels mainly serve as “translator loophole” stations, AKA “Metro Stations”

As far as the new ownership by DTS goes; I will reserve judgment until they do something with it.