Decommissioning transmitters

I was at a transmitter site a few days ago scrapping a Continental 814-R1 transmitter. I started thinking (always a dangerous thing) about how many of these units I have decommissioned over the years.  It turns out, quite a few:

Make/ModelYear new*Year removedStationDisposition
GE BT25A19481994WPTRDonated/scrapped
Gates BC5P19602004WWLODonated
Harris MW5A19822000WLNAScrapped
Gates BC1T19612001WLNADonated
Harris FM20H319722001WYJBScrapped
RCA BT1AR19602001WROWDonated
Harris BC1G19722001WDFLAbandoned
Harris FM20H319712005WHUDScrapped
BE FM30A19882005WHUDCannibalized
Harris FM5G19722008WSPKScrapped
Mc Martin BF3.5K19762011WCTWScrapped
RCA BTF-10ES19782011WRKIScrapped
Gates BC1T19642011WINEScrapped
Continental 315F-R119852013WVMTDonated
Collins 813F19752014WKXZScrapped
RCA BTA1AR19652014WCHNScrapped
Collins 813F219782015WKXZScrapped
Collins 830D-1A19682014WKXZScrapped
Harris FM20H319722013WYJBScrapped
Harris BC5HA19732013WROWScrapped
Harris FM10H19712013WMHT-FMScrapped
Harris FM2.5H319732015WEXTScrapped
Mc Martin BF3.5K19722014WSRKScrapped
CCA FM5000G19802015WTBDScrapped
RCA BTF1E19722016WZOZScrapped
QEI 695T3.519962015WBPMScrapped
QEI 695T519962015WBPMScrapped
Harris HT3.519972015WUPE-FMScrapped
Harris Z5CD19972015WXPKCannibalized
Energy Onix SSA100020002015WDHICannibalized
Harris MW119822016WPUTAbandoned
Mc Martin BF1K19822016WSULScrapped
Mc Martin BF3.5K19822016WSULScrapped
Continental 814R119802016WDBYScrapped
Broadcast Electronics FM35A19862017WEBECannibalized
CCA FM-1000D819732018WDLAScrapped
Collins 828E19782018WSYBScrapped
Gates BC-1H19712018WHUCScrapped
Gates BC-1J19542019WBECScrapped
Gates BC250GY19692019WSBSScrapped
Nautel V-7.520092021WSPKCannibalized
Nautel V-1020072023WHUDCannibalized
Nautel V-1020072023WHUDCannibalized
Harris FM1H319702024WBEC-FMScrapped

*In some cases the “Year New” is a guess based on when the station went on the air.  Before you write me and say “But model XYZ transmitter wasn’t made until 19XX, I did not look at every nameplate and write all the information down as I did this.

Like everything else, there is a process to this.

RCA BTA-10U AM transmitter
RCA BTA-10U AM transmitter

First, if the transmitter was made before 1978, the possibility of PCB capacitors and transformers exists. In the case of the GE BT25A, massive amounts of PCBs needed to be disposed of properly. According to current federal laws, ownership of PCBs and PCB-contaminated items cannot be transferred. Thus, the transformer casings were cleaned and taken to Buffalo to be buried in a PCB-certified landfill.   Otherwise, most other transmitters, such as the RCA BTA-10, may have a few PCB capacitors and perhaps the modulation transformer.  Those items can be disposed of by calling an authorized environmental disposal company like Clean Harbors.

The rest of the transmitter is stripped of any useful parts.  Things like vacuum variable capacitors, rectifier stacks, blower motors (if they are in good condition), HV power supply contactors, unique tuning parts, whole control and metering boards, tube sockets, etc.

The remaining carcass is then disassembled and hauled off.  I have a guy that will do this for relatively little money.  He takes the transmitter back to his warehouse cuts it up, sorts the various metals out, and then takes it to the scrap yard.  This includes cutting all the windings off of transformers and power supply chokes, sorting out the brass and copper tuning parts, etc. Thus, most of the transmitter is recycled. Things like vacuum tubes, circuit boards, and other plastic parts are disposed of as e-waste.

The Gates Air Flexiva 1

We just finished installing one of these units for one of our clients. This is the third one that I have dealt with in the last two years. I have to say, these transmitters are pretty cool.

Gate Air, Flexiva 1 running at 990 watts
Gate Air, Flexiva 1 running at 990 watts

We also installed a 7/8 transfer switch and a 1.5 KW test load:

New installation of transmitter, transfer switch and test load
New installation of the transmitter, transfer switch, and test load

Another view:

Transmitter installation
Transmitter installation

New transmitter rack, processor, and remote control:

New transmitter installation
New transmitter installation

The former main transmitter, the venerable BE FM1B:

Broadcast Electronics FM1B transmitter
Broadcast Electronics FM1B transmitter

View of the 7/8 inch coax going out of the transmitter room to the tower:

Coax out to tower
Coax out to the tower

Rarely, if ever, have I worked with a 7/8 rigid transmission line. Usually, it is a 1 5/8 or 3-inch line, which requires some amount of patience when installing.

Nice little transmitter site upgrade project.

North Adams tower update III

And final.

It has been a year and a half since the tower collapse in North Adams, Massachusetts.  Since that time, WUPE-FM (Gamma Broadcasting), WNNI, and W266AW (New England Public Radio) have been operating with STAs at lower than licensed power.   We have completed the installation of the combined antenna, filters, and combiners and now all stations are back to full power.  Here are a few pictures of the transmitter room:

WUPE-FM and WNNI transmitter racks, North Adams, MA
WUPE-FM and WNNI transmitter racks, North Adams, MA

WUPE-FM (left-hand rack) is using a Crown FM-2000 transmitter, loafing along at 1,060 watts. WNNI (right-hand rack) is using a Gates Air Flexiva 2 running at 1,650 watts. Those stations are combined with a Shively Combiner:

Shively combiner
Shively 2-way star junction combiner

We are still doing some grounding and neatening work behind the racks:

Behind racks
Behind racks

The Shively versa tune antennas that were mounted to the wooden utility pole as emergency antennas will be retained as backup antennas for both stations.

Transmitters for WUPE, WNNI and W266AW
Transmitters for WUPE, WNNI, and W266AW

We share the room with Access Plus, which is a wireless internet service provider in western Massachusetts. Their stuff is in the open-frame racks to the right of WNNI.

Another view:

Transmitter racks for WUPE-FM, WNNI and W266AW
Transmitter racks for WUPE-FM, WNNI and W266AW

TL;DR: Tower collapses, and the facility is rebuilt better than before.

The Gates Air FAX-10

This is the first one of these transmitters that I have installed. This particular unit is analog only, but there is lots of room left over for an HD exciter if need be.

GatesAir Flexiva FAX-10, 10.000 watt FM transmitter
GatesAir Flexiva FAX-10, 10.000-watt FM transmitter

The size of a 10 KW FM transmitter these days is pretty small, basically taking up the equivalent of one rack. This is a relatively small transmitter room, the old tube transmitter basically took up the entire room. With this unit, there is room to install a full power spare, if that was desired.

GatesAir Flexiva series RF modules.
GatesAir Flexiva series RF modules.

RF modules use LDMOSFET devices, each module has a power output of approximately 1,600 watts.

GatesAir Flexiva FAX10 power amp section
GatesAir Flexiva FAX10 power amp section

There are eight power amp modules and seven switching power supplies.

GatesAir FAX10 transmitter on the air
GatesAir FAX10 transmitter on the air
GatesAir FAX10 power output
GatesAir FAX10, licensed transmitter power output

One issue at this site, there is no reliable three-phase power available.  There was a three-phase open delta, but man, that thing scares me a little bit.  Since this is a single-phase setup, I was curious to know what the current draw on each leg was at full power. I measured with my clamp-on ammeter; 54.3 Amps at 120 volts, or 6516 watts per leg. Overall power draws 13,032 making the AC to RF efficiency 65.2%. VSWR calculates out to 1.21, which is not great.  I think the antenna could use a little bit of tuning love.