FM – Page 7 – Engineering Radio

GatesAir FLX-40 one year in

I was at the WEBE transmitter site recently and took the time to look over the transmitter we installed last year:

GatesAir FLX-40 transmitter, WEBE Bridgeport, CT

Overall, I would say that this transmitter has been very reliable. We had to install a UPS for the exciter and HD Radio exporter, but that is not a big deal. During the first power outage, the exciter went dark first. It took longer for the transmitter controller board to lose power, in the interim the controller turned the transmitter power all the way up. When the generator came online 10 seconds later, the transmitter returned to operation at 41.5 KW. This, in turn, caused one of the other field engineers to freak out and nearly lose his mind (stay away from the brown acid, FYI).

I installed the UPS a few days later.

WEBE TPO 35.3 KW with HD Radio carriers on

The transmitter power output is 35.3 KW, which is getting into the semi-serious range. The reflected power goes up when it gets warm out and goes down in colder weather. Over the winter, it was running about 50 watts. Even at 138 watts, that represents 0.004% reflected power. The TPO forward goes to the 6 bay, 1/2 wave spaced antenna side mounted, 470 feet (143 meters) AGL. The station covers pretty well.

WEBE Pump station, pump is running 2/3 speed and fans are running at about 1/2 speed

Overall, I would give the liquid cooling system an A grade. The transmitter still dumps a fair amount of heat into the room from the RF combiners and PA power supplies. Most of the heat, however, ends up outdoors. Previously, we had two Bard 5-ton AC units running almost full-time. Now, only one AC unit cycles on and off except for the hottest days of the year. The outside temperature when this picture was taken was 81 degrees F (27.2 C).

Next year, we will have to send a sample of the coolant to be analyzed.

I have had good experiences with the GatesAir FLX/FAX series transmitters. I would recommend this to a friend.

Shipping Container transmitter site

I do not particularly like these. I know, they are relatively inexpensive, easy to come by, easy to install, etc. However, a shipping container was not designed to house a transmitter, they have certain drawbacks. These are, in no particular order:

Air conditioning. Using a traditional Bard-type equipment shelter HVAC unit requires cutting through a lot of fairly heavy gauge steel. What’s more, the steel walls are uneven, requiring a filler.
They are by necessity, fairly narrow. Arranging racks and transmitters along the length of the unit restricts access to either the front or the back of the equipment. Meeting NEC clearance requirements for electrical panels, transfer switches, and disconnects can pose problems.
They are not very tall. Mounting overhead equipment can be problematic as one does not want to drill through the top of the container. Crosswise unistrut is one solution, but it lowers the overhead considerably.
Electrical work is slightly more dangerous. Doing any kind of electrical work, troubleshooting, repairs, etc is a little more nerve-racking when everywhere around you is a metal surface at ground potential.
They are difficult to insulate against cold and heat.
The door-latching mechanisms bind, wear out or otherwise fail over time.

All of those things being said, I am now rebuilding a transmitter site in one of these shipping containers.

Inside view of shipping container transmitter site

Fortunately, the original electrical work was not bad. The transmitter is a twenty-year-old BE FM10B, which will be retained as a backup. The new transmitter is a Gates Air FAX-10. We have installed several of these Gates Air transmitters in the last two years or so and they seem to be pretty solid units. This is the second 10KW unit I have installed.

Gatesair FAX-10 transmitter in Middle Atlantic Rack

We decided to install the FAX-10 in a Middle Atlantic rack since we did not have a whole bunch of extra room for a separate transmitter rack. The 1 5/8 inch coax switch is installed in the top of the transmitter rack along with a Tunwall TRC-1 switch control unit. The other rack will have the STL and all other ancillary gear. My idea is to have nothing in between the door and the FM10B so it can be easily removed when that day comes. Something, something about planning ahead since it will be likely myself removing the FM10B.

Radio is dead? Don’t tell these guys then…

WXHC in Homer, New York will never be listed on the NY Stock Exchange. Is that bad?

They don’t think so. A small class A FM station, one of many that signed on in the early 1990s as part of the 80-90 drop-ins (FCC docket 80-90, for those unfamiliar). Many of these stations did not fair too well and ended up being absorbed by larger stations and groups starting with the first wave of ownership deregulation in 1993.

WHXC has remained under the same ownership since it signed on in 1991. Eves Broadcasting is a family operation, employing maybe half a dozen people. Their studios and offices are on the third floor of the Bank of Niagara right in the center of town. The facility is very nice. Like any successful radio station, its focus is the community they serve. The format is “Oldies” but they also broadcast high school football, Syracuse sports and so on. They host a yearly Blue Grass festival on the village green.

The air studio has an Arrakis console and uses BSI Simian automation software. They have live DJs from 6 am to 6 pm, local news, weather, sports, etc.

The production room has a BE Spotmaster 8S200A console from 1978. Aside from needing some power supply capacitors, it still works relatively well. However, as the owner’s son said; that thing belongs in a museum.

BE Spotmaster line input card. Probably can still get all these parts if we wanted to.

I forgot to take pictures of the transmitter site when I was there. Next time.

We will be working on several projects for these folks, so I will keep you posted on the progress.

Pittsfield Massachusetts’ newest “Metro-Station” 103.3, W277CJ

We have been poking away at this one for the last year or so. It seems that the previous owners of Berkshire Broadcasting had filed for a translator to rebroadcast WNMB, (100.1 WUPE-FM) North Adams in downtown Pittsfield, during the great translator rush of 2003. When the CP showed up in the mail last March, the current owners were quite surprised.

After looking at the Construction Permit, we made some modifications;

Moved the transmitter location from 100 North Street to 1 West Street (Crowne Plaza Hotel) which is the tallest building in Pittsfield. Antenna AGL is 44 meters (145 feet).
Changed the rebroadcasting station from WUPE-FM, North Adams to WUPE-AM Pittsfield
Changed the antenna to non-directional
Changed the ERP from 48 watts to 100 watts

We were able to make those antenna and power changes because we changed the parent station to the local AM station, WUPE, 1,110 KHz. The previous power/pattern was submitted to keep the translator signal within the 60 dBu contour of the FM station in North Adams.

This, I feel, is the best use for an AM to FM translator. WUPE-AM is a class D station with no nighttime service. Adding a nighttime service greatly increases the station’s value to the community. While the 100 Watt translator does not cover nearly as much as the 5,000-watt AM station, the transmitter location is right in the center of Pittsfield, so coverage of the population center is excellent.

The view from the top of the Crowne Plaza is quite spectacular. I am pretty sure I will have a lot of transmitter maintenance to do right about the middle of October.

The installation is fairly straightforward:

W277CJ installation, roof of Crowne Plaza, Pittsfield, MA

W277CJ transmitter in outdoor enclosure — W277CJ transmitter in an outdoor enclosure

The outdoor enclosure is a DDB POD-16DXC which is rather nice, it comes with rack rails and a thermostatically controlled fan.

The antenna is a Shively 6812B with RADOMES. The transmitter is a BW Broadcast TX600v2. I really like these transmitters, they are well-designed and rugged. We have yet to have a single failure of one of these units in the field.

The station ERP is 100 watts, so a small bit of calculating is required to arrive at the proper station TPO. I find it easier to make all these calculations in the decibels per milliwatt (dBm) unit domain, then convert them back to watts. Thus, the ERP is 100 watts or 50 dBm. The antenna has a gain of -3.4 dBm. We used 25 feet of LMR-400, which at 103.3 MHz, has a loss of -0.26 dBm. The total losses are -3.66 dBm, making the necessary TPO 53.66 dBm, 232.27 watts, or rounding down to 232 watts.