Comments for Engineering Radio

Comment on Communications infrastructure vulnerability by J. Aegerter

J. Aegerter — Thu, 11 Mar 2010 16:46:24 +0000

Instant gratification is the big thing these days with no thoughts about alternative solutions. I see this everywhere. The cellular industry is full of egotistical stuffed shirts that could not manage anything if there was not a pent-up demand. They have all “hugged” GPS. I am one that hasn’t. WWV is still on the air on a bunch of frequencies that provides substantial coverage throughout the country. But this sheep-like following of a guvmint system must be appealing. Back when Bush declared “Desert Shield”, I received a call from the State Air Force MARS director asking if I could assist the Air Force on an emergency. I said that I would be happy to. It turns out that the large city encompassing a large airport wanted to have a “summit conference” before they would let the Air Force install a 100 Watt VHF DES repeater on a water tank. Airport security was the prime function, and the Commander wanted to move fast. Needless to say, I ordered the antenna and transmission line, and I had them on the air in one week on my tower. I then got a visit from an Air Force Colonel, who flew in to inspect the installation. He was pleased with the job and we got talking about terrorism. The threat of EMP and the availability of shoulder fired missiles was discussed. GPS was also discussed and at that time “Selective Availability” was turned on. He was definitely an ‘old school’ military man, who was for keeping vacuum tube equipment in good order in case of emergency. I think EMP is bubbling under, and may be a real threat in the future. The problem is that the majority of people take things for granted these days and can’t even cope with a runaway demon Toyota! They are programmed to first call 911 before they can think of simply turning off the ignition or shifting into Neutral!

Comment on Future of AM radio by admin

admin — Thu, 11 Mar 2010 12:12:41 +0000

It’s not just radio either, it’s everyone’s business. Soon, the banks are going to rule the world.

Comment on Future of AM radio by Josee Fritz

Josee Fritz — Tue, 09 Mar 2010 00:14:43 +0000

Your comment “The banks are in the radio business” is very accurate. It pretty well sums up the current problem. the banks wanted to invest and when it bottomed out they found themselves holding the morgages to houses they didn’t want to live in… But now, permanently tethered they’ve become insidiously incompetent landlords.

Comment on Future of AM radio by J. Aegerter

J. Aegerter — Wed, 03 Mar 2010 23:12:16 +0000

I have worked in this industry for four years while attending college about 40 years ago. It was basically a gold mine then as just about anybody could make money with little effort. FM air time couldn’t be given away and AM was King Kong. With the myriad of programming sources out there today, AM has been drastically fragmented. I have always believed that AM radio was a local business kind of like One-Way Paging. The big boys usually always screw things up, with the total emphasis on profits. Don’t get me wrong, I love profit, but my profits have come in by “over-performing”. The big boys don’t get this because the stations they own are only a number in a ledger. I believe a local owner can still make a living running an AM station, but it is definitely getting harder. Perhaps an adjunct to another business, like the way the industry started with Jack Poppelle playing Christmas Carols on WOR back in the day. L.Bamberger and company let him put the little station on the air to sell radios in their NYC department store, and it worked real well. He ended up marrying the head of the Housewares department after his radio broadcasts sold an overstock of China plates that weren’t selling. Now that is RADIO BROADCASTING!

Comment on Owner says don’t plow the road by J. Aegerter

J. Aegerter — Wed, 03 Mar 2010 17:13:22 +0000

This is one reason I dislike diesel generators. They can be hard starters in cold weather when you may need them the most, exhibit fuel souring from sitting idle over a period of time, and the high cost of these fuels these days. All of our standby generators are Liquid Propane fueled except for one diesel, and that one is the most finicky. Propane is a perfect fuel, the price nearly always goes down in July of each year, and no need for bleeding lines since it “boils” around -30 degrees F thereby always exhibiting pressure into the fuel line. Our maintenance program is to check all of out propane tanks every June by reading pressure gauges on each tank, and ordering new gas when the price is lowest, usually in July or August. In this manner, a station should be able to coast through a blizzard. Plowing out remote sites is costly, and we only plow out our busy multi-user antenna sites. We have 4WD Dodge pick-ups and have never had a problem getting into a site, except when there was severe drifting over 3 feet high. I personally have always prepared for the worst, and with our constant attention to our generator sets, we haven’t had any problems in over 20 years. I have noticed that many broadcasters buy a generator and that is the end of story. Checkouts and routine maintenance is seldom done. I pulled a dipstick on a station’s Generac generator set with a GM V-8 and the oil looked like it had never been changed. It had a mustard type yellow substance signifying oil breakdown that was probably caused by short cycling (exercising). The quality of the oil is critical in these unattended applications, and a full synthetic would be my recommendation from day one of the generators life.

Comment on AM radio by J. Aegerter

J. Aegerter — Tue, 02 Mar 2010 00:38:48 +0000

Your 580 kHz. Ampliphase would have been a BTA-5L series as my 1973 RCA catalog proudly displayed it. It used a real dud tube the 7094 which only RCA made to my knowledge. My preference was always high-level plate modulated AM transmitters because of the simplicity and stability into changing load impedances. Granted, they use heavy components, but your old BT-25 lasted long and gave faithful reproduction without much but tube replacements for nearly 50 years. That GE transmitter was a good investment for the owners of 1540 and brought in huge revenues during its time on the air. I hate to say it, but I’m not really impressed with the transmitters of today. Cheap switching power supplies, more reliance on microprocessors and firmware, along with special solid-state devices in a changing time frame that seems to relish buying a new transmitter every few years. In other words, a disposable piece of trash with a huge initial investment. If I buy a AM station, you may think I’m crazy, but I would run a personally rebuilt tube type transmitter with some modifications to improve transmission quality. That would be fun to play oldies that were most likely recorded with tube-type audio consoles, and now broadcast with a tube-type transmitter with attention to the goal of perfection in transmission quality. I have a hunch my station with my plans of web access (not streaming) and localism might just click with the general public. That would be fun to do in my mind.

Comment on Owner says don’t plow the road by admin

admin — Mon, 01 Mar 2010 21:08:43 +0000

My wife comments that it is both funny and sad

Comment on Owner says don’t plow the road by Daniel

Daniel — Mon, 01 Mar 2010 14:39:26 +0000

lol, I’m not sure if that’s pretty funny or pretty sad…

Comment on AM radio by admin

admin — Mon, 01 Mar 2010 13:58:56 +0000

I did indeed have the later model BTA-5 transmitter, I don’t remember the letter, it might have been an L. It was installed in 1976 or so, had the solid state exciter and was on 580 kHz, so basically, everything was against it. It was a six tower directional night, non-directional day. As I recall, the day tower was pretty broad, the night array was fairly narrow.

I hope that IBOC for AM dies an inglorious death.

I have been fooling around with a Tuned Radio Frequency receiver for AM based on a MK484 IC. It is an exceedingly simple design and yet sounds far, far better than any store bought AM receiver manufactured in the last 20 years. The TRF design seems to be selective, sensitive, stable, etc. One little 3 pin IC, some resistors and capacitors and off you go.

People have been complaining about AM’s fidelity for years, it is not the technology itself, it is the crappy receivers that make it sound bad.

Anyway, I’ll put some pictures up when I am finished.

Comment on AM radio by J. Aegerter

J. Aegerter — Sun, 28 Feb 2010 00:38:51 +0000

I am curious if the admin had a 5 kW Ampliphase model BTA-5L. It had the later solid-state exciter which I hear had problems. My Ampliphase was the BTA-50H built in 1964 and delivered in early 1965, going on the air during the summer of 1965 to proof the 9 tower antenna array with dead carrier while the old BTA-5E remained on the air 20 kHz. higher in frequency. I was hired right out of high school in February, 1966 while a freshman in EE for weekend sign-on at the 50 kW site about 20 miles south of the BTA-5E site. I spent a lot of time looking the 50H over while at 10 kW early in the mornings before sunrise. The tube-type exciter was proven in the BTA-50G which went through many modifications. It was extremely stable. Personally, I believe the 50H was the best Ampliphase out of the entire run of these transmitters. The 50J and 5L used a new solid-state exciter that was pushed out the door with no track record, and I am told was very problematic. This is an instance where the tube design was far superior, but of course, the state of the art had shamed RCA into a poor design. The other thing I have heard about Ampliphase rigs is that they do not perform well below about 800 kHz. My unit was on 1130 and it worked real well. However, we had a trapezoidal pattern displayed on it continuously with a Techtronix 5 inch oscilloscope. The only problem I had with the beast was that it would shut down by itself without warning. And, it happened to me one time when of course I was out at Tower #5 reading base current. I opened the tuning house door, pulled out the shorting switch and zero current! I ran back into the transmitter building (about 500 feet away) and of course the phone was ringing off the hook with an irate studio engineer asking what I was doing! Luckily, I had the BTA-10U filaments still on from earlier, and switched over to it immediately. I re-started the 50H into the dummy load, and of course it came right up. I called the studio engineer and told him what had occurred and he then stated that the same thing had occurred earlier in the week! There were no storms, or anything that I could put my finger on as to the trouble. I switched back to the 50H and watched it closely for overloads, and of course there were none. After about an hour, I went back out to finish reading the base currents of the day array and there were no problems. When my shift ended, I mentioned it to the guy who hired me, and he said the same thing had happened to him on the day shift during the week. The following week when I came in, I noticed on the log that a 2D21 thyratron in the storm detection circuit was replaced, and that further close observance of the transmitter should be adhered to. There were no more problems, and apparently the defective 2D21 was the culprit. As far as Ibquity is concerned, it is simply terrible engineering for AM, and FM as well. An AM transmitter with full fidelity (50-10000 Hz.) and low distortion feeding a low Q load impedance is superior to Ibquity, and the only way to go. I believe Ibquity will be gone on AM soon, and hopefully FM also. As far as the positive modulation peaks on AM transmitters is concerned, many plate modulated transmitters are good for about 130% maximum, and I will never understand why the FCC came out with the 125% maximum. The few transmitters that were capable of higher positive peaks (like the 50H) were few, and were very narrow when tuned correctly. I could drive away from the site on my way home and be in the main lobe, tune off the sides of the carrier while listening to music with huge high-frequency content and the emission was extremely narrow. Of course with the trapezoidal pattern showing excellent linearity, it was proof in the pudding.