Almost Eighteen Years

I do not know what the record is for the longest tube life, however, this particular tube lasted 17 years, 11 months and 23 days.  That’s 157,596 hours.

I had written about this almost five years ago: http://www.engineeringradio.us/blog/2014/12/longest-tube-life/

The last one was last fall: http://www.engineeringradio.us/blog/2018/09/i-almost-hate-to-say-anything-but/

Eimac 4CX12000A power tube

This was installed new in a Broadcast Electronics FM20T transmitter which was placed on line on June 6, 2001.  It lasted until May 28th, 2019 with almost no down time.  Towards the end, the emissions started dropping off and we increased the filament voltage up to 10 volts.  When you have to increase the filament voltage, that really is the end for a tube.

The new tube was put in and I carefully marked out the date in the maintenance log.  The hour meter on the transmitter stopped working several years ago.

Prior to this, the longest tube life I’d experienced was an EEV 4CX35000C from an MW-50B transmitter RF section.  When that tube came out, it looked like it have been on fire.

The Broadcast Electronics STX-5 transmitter

Another install, this time a new BE product. I am familiar with the BE FM “C” series transmitter. Those are pretty solid units and we take care of many of them.

BE STX-5 LP transmitter
BE STX-5 LP transmitter

This new version of transmitter looks like it has a little bit of Elenos in its DNA.  Perhaps I am wrong about that.

The STXe exciter is an all purpose analog/digital unit that will do standard FM stereo, hybrid FM +HD radio, HD radio only, DRM+, or FM and DRM+.  I like that.  It gives the owner lots of options with regards to future planning.  Frankly, I would love to see some DRM+ testing done in the US.

We have actually installed a couple of “C” series transmitter with the STXe exciter as well.

BE FM2C with STXe exciter

The rest of the transmitter consists of four RF amps and an output combiner all in a short rack.  Frankly, if I were ordering one of these units, I’d order the taller rack.  Not that I am getting old or anything like that, but stooping over to program the date/time, frequency and power output introduced a slight discomfort in my lower back.

BE STX-5 LP controller/exciter
BE STX-5 LP controller/exciter

Running into the antenna.  At 4.1 KW, 18 watts reflected power is slightly high.  This antenna has always had a little bit of reflected power.

"The chicken coop, " WHUC and WZCR transmitter building
“The chicken coop,” WHUC and WZCR transmitter building

The building I installed this in is nick named “The Chicken Coop,” likely because it used to be an actual chicken coop.  I am not kidding.  The site was originally just the AM station (WHUC).  That station had a different transmitter building located some distance away which was fed with open transmission line.  This building was put in place sometime around 1969 when the FM station signed on as WHUC-FM (now WZCR).  It has seen better days, but we are working on fixing some of the issues with air conditioning and cleanliness.

Remains of open wire transmission line left over from orginal 1947 installation
Remains of open wire transmission line left over from original 1947 installation

The transmitter fired up without any issues and sounds much, much better than the QEI which it replaced.

Tired old QEI transmitter
Tired old QEI transmitter

The QEI transmitter had problems over the years, mostly burned out resistors in the RF combiner network.  It has since been scrapped.

Another FAX 5 install

At the risk of becoming redundant, here are a few pictures of a GatesAir FAX-5 install recently completed in Westerly, RI.  This was installed in a recently vacated Verizon cell site next to the old transmitter building.  The old transmitter building and the equipment contained therein had seen better days, to be sure.

UPDATE:

As requested, the only pre-installation photo I can find:

Some Verizon equipment still in place
Some Verizon equipment still in place

That photo was taken back in October 2018, when we first looked at the Verizon shelter as a viable alternative to the current transmitter site.

FAX-5 transmitter with fancy logo, placed in position
Transmitter in place, AC mains and RF connections made
Ground strap installation
Test mode, clamp on AC current meter, measuring amps per leg at full power
FAX-5 transmitter and equipment rack, on the air
Transmission line, supported by unistrut
Delta coax switch and Electro impulse dummy load, salvaged from old installation
FAX-5 running into antenna for the first time

Overall, the transmitter sounds great.  Much better than the old unit which had an AM noise problem.

If it wasn’t so far away, this would have been a pretty easy project.  There were minor miscues along the way that added up.  I will say that I learned a few good life lessons about the reliability and responsibility of people.