tech stuff – Page 63 – Engineering Radio

Gates FM5G transmitter

Takes its rightful place in the world today, the scrap heap:

As EDWARD I of ENGLAND once said, “A man does good business to rid himself of a turd.”

Of course, he was speaking about Scotsman John Balliol and not some old cranky FM transmitter, but I understand that feeling. The Gates and later Harris transmitters always seemed to be somewhat less than top-notch. The 5G was no exception to this rule. The final step for tuning the transmitter was to turn off the lights in the room and look down through the screen on top to make sure there were no little arcs in the PA tuning section. It also had a way of self-oscillating, which could make for some exciting tuning.

Gates FM-5G transmitter prior to disassembly

Goodbye, I will not miss you.

In one of my past jobs, I worked in a RCA town. I worked there long after the broadcast arm of that company went out of business, however, all of the broadcast transmitters, AM, FM, TV were made by RCA. I had an RCA FM-20ES1 which was 22 years old, built like a tank and just kept going along. I think that transmitter was finally destroyed in a fire, caused by it’s replacement transmitter.

Old Collins, Contenental, RCA and even Broadcast Electronics transmitters had some heft to them. Of course, not every RCA transmitter was well thought out, the amplifuze series of AM transmitters were a maintenance nightmare.

If it ain’t broke, break it

One thing that I find a little annoying is the continuing need to reboot everything at some interval. Computers in the studio, audio vault servers and workstations, e-mail servers, files servers, network routers, and so on. Got a problem, first thing to do is cycle the power off and on…

One of the most irritating pieces of equipment is the audio processors on one of our FM stations. A few years ago, we purchased the whiz-bang Omnia 6 processor. Every 6 or 8 months the thing losses its mind and sounds terrible. The station gets all bassy and the high-end sounds distorted. I have tried everything I can think of to prevent this, including installing a UPS, extra grounding, extra shielding, software updates, etc. In the end, it just has to be rebooted, which of course, means several seconds of dead air. Naturally, this processor is at the FM transmitter site, which it is difficult to get to.

Truth be told when it is working, it does sound pretty good on the air, but is it $10,000 dollars better than the older Optimod 8100A? No, it is not.

The old Orban Optimods sound pretty good as long as they are re-capped and aligned every so often. If fact, our number one billing station has an AC format and uses an Optimod 8100A and nothing else. Our other station in the same market uses an Optimod 8100A and a pair of Texar Audio Prisms. In the ten years, I have been working for this group of radio stations, I have never had to reboot the Optimod or the Audio Prisms, they just seem to work continuously without problems. Imagine that.

I have seen this called a “retro audio chain” by some. Nothing retro about it, but a little care and feeding and I’d stack this equipment up against an Omnia 6 any day of the week and twice on Sunday.

This is a grainy video of an 8100A in action:

That was taken in our rack room using off-air audio on the rack room speakers and a cheap video camera. You get the idea.

So here is to Frank Foti and his marketing gurus that have sold all of the program directors in America on the need to “update” their air chain processors, because, you know, the Optimod, that is old skool.

Lightning strikes

For about 4 years, I lived in a house next to a four hundred-foot radio tower. Although I never actually saw lightning strike the tower, I heard it several times. Like everything else, after a while, you get used to it.

This is a video of lightning hitting the WSIX STL tower in Nashville, TN. The camera work is a little unsteady, the strike occurs around the 1:36 mark:

Yep, that is what it is like.

Module swap guys

Gone is the day when the radio station engineer had to troubleshoot down to the component level, often crawling in and out of transmitters to get at the suspected part. I for one, spent many a long night at a transmitter site chasing some weird combination of symptoms down to the $0.34 1N914 diode in the directional coupler (see previous post about the MW-50).

It is a skill set now mostly confined to manufacturers’ repair departments, for which they charge a pretty penny. Nowadays, the technician simply slides out one module or circuit card and slides in another. If that doesn’t fix it, panic ensues. I know of several class C FM radio stations that are now relying on the computer guy to fix transmitters, because, you know, it’s cheaper.

To be fair, most engineers are contractors and many of those simply do not have the time to troubleshoot to the component level. So, they ship everything back to the factory and then pass the cost on to their client.

Then of course, most circuit boards these days are surface mount systems, which are hard to work on if you don’t have the right tools. Normally an expensive temperature-controlled soldering station is required, as well as a magnifying glass.

All of these things combine to make circuit board work something to be outsourced. Unfortunately, a night spent troubleshooting was often a great learning experience. I have done some of my best work when my back was up against a wall and I was out of options.

I make the attempt to fix things locally unless the transmitter or other item is under warranty or not having a spare/attempting to troubleshoot will take the station off the air. I think it is important to keep abreast of technology and keep my troubleshooting skills up to par. Besides, I find it gratifying that at least I can still fix things.