It was ten years ago that I registered the domain name for Engineering Radio. A few days latter, I put the first post up. It is still there. Those were different times for me personally and the business in general. There certainly have been trials, but it has never been dull.
Periodically, I go back through the posts and delete anything that is no longer relevant. I would estimate about 1/4 to 1/3 of the content has been deleted over the years. It is a good exercise to go back through and read what I wrote previously.
Currently, the stats are:
787 published posts, there are a few in the wings waiting to be finished
Approximately 200 page views per day
170 RSS feed subscriptions
I lost the country counter, but I believe the split is still about 60/40 US readers vs other countries.
I will continue on with this thing for as long as I feel it is worth while.
Yesterday I took, what I hope to be, my last walk across Pleasure Beach Island in Bridgeport, Connecticut. The task at hand was repairing the antenna array for WICC. There turned out to be several issues which were addressed in turn.
The trouble started when the feed line between the ATU and the tower became disconnected during a storm. That consists of a 1 inch copper pipe extending from the ATU feed through insulator up to a brass plate suspended between the four tower legs by hard drawn single 0 copper wire. The feed line separated at the brass plate which, unfortunately, is approximately eighteen feet in the air.
The feed line was repaired, but not effectively. By the looks of the picture, the brass plate never got hot enough to accept the solder.
After the feed line was re-repaired, other issues became apparent. The base impedance of the tower was still off and the array was still way out of tolerance.
It was noticed that several bypass capacitors on both of the tower lighting chokes where blown open. Those where replaced and the tower lighting chokes where checked for shorted turns. While it is always nice to replace burned out parts, this did not correct the problem.
Finally, we were back at the base of the tower with the defective feed point and a decided to grab the pipe and give it a good shake to see if it came apart again. It did not, but then I realized that that tower was supposed to be back in the circuit and I did not receive any RF burns for my carelessness.
We dug into the ATU and discovered that the input capacitor was marginal and there was a large crack in it. The output capacitor seemed to be completely open. The base current that we were seeing on the base current meter was being induced by the other tower. It all began to make sense.
The parts were ordered and shipped and I made another trip out to install them myself.
Thus, on this particular day, I had my tool bag, an OIB-3 with fresh batteries, my cordless drill, drill bits, and three type 294 mica capacitors. I took the drill because the new capacitors were quite a bit larger than the old ones, so I needed to move the stand off insulators to remount them.
The walk from the end of the dock to the transmitter site is approximately 900 meters or 0.55 miles, according to google maps. On a nice day, it is a pleasant walk. On not so nice days, it can be less so. It was foggy with light drizzle. Not enough to get wet right away, but enough to get slowly soaked while working on the ATU repairs.
With the new capacitors installed, I needed to adjust the array back into tolerance, which didn’t take too long. I made a short video of the station running at full power showing the antenna monitor readings for both the day and night patterns. Then packed up and headed back to the dock.
I wanted to take a set of monitor points, but the FIM-41 had been moved to another location. That was fine, I was getting pretty uncomfortable in my wet clothes, so I headed home.
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.
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.
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.
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.
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 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.
The transmitter fired up without any issues and sounds much, much better than the QEI which it replaced.
The QEI transmitter had problems over the years, mostly burned out resistors in the RF combiner network. It has since been scrapped.