In this time of COVID-19

As most of you man know, I live in New York State (Hudson Valley region).  This is very close to the COVID-19 outbreak in Westchester County.  There has been one confirmed case in my town.  As such, we are experiencing the outbreak ahead of the curve from the rest of the country.  School has been cancelled for at least two weeks and perhaps indefinitely.   All public gathering places are closed; restaurants, bars, movie theaters, malls, churches, etc.  As a radio engineer, the COVID-19 virus has a several implications:

  • Things are still going to break and will need attention. The good news is that most transmitter sites are unmanned. The only social interaction my be during the travel phase (getting fuel, food, etc).
  • Many studios and offices are being abandoned as well. Over the last few days, we have set up DJ’s to operate from their houses.  Most sales and office staff have been told to work from home.
  • Broadcasters have been designated critical communications infrastructure, The Department of Homeland Security has issued letters that allow travel and procurement of fuel during the national emergency for critical personnel.
  • I managed, prior to the store shelves being emptied this weekend, procure some PPE.  I don’t know how effective it will be, but anything is better than nothing.
  • Since Hurricane Sandy, I have had in place many emergency supplies and equipment needed to restore service in the event of a long term interruption of basic services.

There are many long term economic implications. For commercial radio stations, the loss of income is going to be extreme.  As the virus has spread, businesses have cancelled pretty much all advertising.  During past disasters, radio was often the only means of getting information to the general population.  I am not sure if this is still the case.  How relevant is radio these days?

Automation Systems

Radio Automation Systems are nothing new under the sun. As Marconi tapped out his famous S, he was likely thinking “We should get a machine to do this…”

Broadcast stations have been installing different types of automation since the mid 1950’s and early 1960’s.  It was touted as a way to free up announcers so they could do more important things.

While cleaning out an old studio/transmitter building and getting things ready for demolition, I found a stash of old product brochures for various automation systems from the 60’s, 70’s and 80’s.  It looks like the previous owner used to go to the NAB every year.  How many radio guys got their start on the overnight shift changing out reels?  I know a few.

Gates automation system brochure, circa 1965
Gates automation system brochure, circa 1965

The Gates Radio Corporation had a fairly standard reel to reel system in three different configurations.  These systems were pretty pricey in their day.  According to the 1966 price list:

  • The Automate 244 cost $7,275.00 ($58,837.00 in 2020)
  • The Automate 484 cost $12,210.00 ($102,946.00 in 2020)
  • The Automate 1007 cost $17,150.00 ($138,799.00 in 2020)

Those are for stereo systems, mono systems cost about $500.00 less.  Each one of those systems ran one station.

Gates Automate 244 events thumb wheel
Gates Automate 244 events thumb wheel

The larger the system, the more events it could trigger.  I have never run into one of these in the wild.

Long form satellite shows began to surface in the early 1980’s. Things like all news formats and overnight talk shows.  I have had nightmares were everyone walks around saying “This is Larry King, you’re on…” while UFO’s fly overhead and next door neighbor, Jim Hightower, buries PCB’s in his back yard not more than 200 feet from his house.

Broadcast Electronics Control 16 radio automation system
Broadcast Electronics Control 16 radio automation system

Broadcast Electronics had the Control 16 system in the 1980’s that ran off of a very basic computer system that could handle 3,000 events with the standard RAM configuration and up to 9,999 events with additional RAM.  This was ideal for multiple program sources; music on reel machines, satellite syndicated talk or music formats, etc.  No longer were these machines simply running the overnights.

Schaffer 901 radio automation system
Schafer 90x radio automation system

Schafer is perhaps the most know analog tape automation, at least to me.  I know of several of these systems that were in operation through the mid 1990’s.  By this time, long form satellite music formats had become the rage.  However, there were still a few stations using reel to reel music services.

I particularly like this flyer from IGM:

IGM (International Good Music) brochure, circa 1971
IGM (International Good Music) brochure, circa 1971

By the mid 1990’s, these tired old dinosaurs where being removed.  Still, the mechanics of the operation were a thing to behold.  It was nice because you could hear the relays snap shut after decoding a 25/35 Hz tone or one of the Mutual Radio be-doops.  The cart-o-matic would chug through the break until the liner fired and then back to the bird.  If there were any issues, one simply needed to stand there and watch which part of the machine malfunctioned.

Schaffer logging system
Schafer logging system

Computer based systems like Computer Concepts DCS, Arrakis Digilink and Audio Vault came along, which got rid of the analog tape.  Instead they stored audio on hard drives.  Those early systems hard drive space was a premium, so usually at least 3:1 compression was needed to fit all the commercials onto the drive space available.

My first brush with Audio Vault was in 1994 at WGY in Schenectady, NY.   It was a pretty good system if you could understand the .ini files.  As the BE tech support guys used to say “You can program it to turn the coffee pot on if you wanted to.”

Nowadays, what used to be a studio location is more akin to a content distribution node.  This rack combines music and commercials stored locally on hard drives with out of town voice tracks and serves as the program source for eleven radio stations.

Radio Automation, 2020 style
Radio Automation, 2020 style

It works remarkably well, as long as the windows operating system stays functional.

Incandescent Indicating lamps

What is wrong with this picture?

WBNR equipment rack
WBNR equipment rack

It is a little bit blurry, but the real problem is that none of the indicator lamps on the phasor or antenna monitor are working.  Those little incandescent 387 bulbs burn out frequently.  It is difficult to tell, at a glance, whether the phasor is in daytime or night time mode.  One also cannot tell which tower or mode is selected on the antenna monitor.

It is a small job to replace them, but it does take some time.  They currently exist in older transmitters, studio consoles, meter back lighting, and other control indicators.  Since I began working in radio, I have replaced hundreds of these little lamps.  I would rather spend my time on more interesting projects.

The 387 bulbs cost about a dollar each and last less than a year, in most cases.  Fortunately, there is a solution to all this.  Enter the based LED replacement lamp.  These little guys have the long life of an LED (100,000+ hours) in a package that is a direct replacement for the Incandescent lamp.  They run about $5.31 each.

Dialight makes a very handy cross reference:

Dialight Incandescent to LED cross reference
Dialight Incandescent to LED cross reference

The entire cross reference section is three pages long and is a part of their PMI catalog.  The full cross reference .pdf can be found here.

Those Dialight LED lamps are available from Mouser, Allied and Newark Electronics.

Time is money.  There are much better things to be doing than going around replacing incandescent indicator bulbs in various pieces of equipment.  At the same time, it is important to know what the status of that equipment is at a glance, which is the reason for using any type of indicator in the first place.  Using drop in replacement LED indicating lamps with certainly save time and money in the long run.

More AM work

I have been working on an AM station lately.   WBNR signed on in 1959 and follows the now familiar AM trajectory; after making bank in the 60’s, 70’s and 80’s, revenue declined, maintenance deferred, yada, yada, yada…

After a stint with a news talk format, the station changed to “Real Country,” a few years ago.  WAT! Music on the AM? Actually, it is doing quite well. The perception is that AM sounds terrible and nobody listens to it.  The stock AM radio in my Subaru (made by Pioneer) sounds pretty good on AM.  I have noticed that when I first tune a station in, it sounds narrow banded, slightly better than a telephone.  However after a second or two, the bandwidth opens up and it can sound quite good.  I have also heard this station playing at several local businesses.  When we turn it off to do maintenance, the phone starts ringing.  Clearly, somebody is listening…

This station is part of a three station simulcast.  The AM station to the north got rid of its directional antenna and added an FM translator a few years ago.  That has made a big difference.  Thus a translator was acquired for this station as well.

The translator was held up by an informal objection filed by Prometheus, Et. Al.  as part of a blanket filing against all new translator licenses by the LPFM advocate.  In any case, the Construction Permit has been on hand for a while, so the owner felt it was time to move forward with building out the new FM signal.

Hoisting the Shively 6812 antenna

Installing the single bay Shively 6812 antenna on the side of one of the night time towers triggered some other things.  A bit of the deferred maintenance was addressed;  new stockade fences around all the towers replaced the original fences put up in 1988. Those original fences were falling down.

4 Tower antenna system, WBNR, Beacon, NY
4 Tower antenna system, WBNR, Beacon, NY

The antenna system for WBNR is actually quite elegant, perhaps even beautiful.  A simple two tower system for the daytime array and a separate two tower system for the night time array.  The night time towers are top loaded, adding about 30.7 degrees in electrical height.

The far tower
The far tower

The CP for the translator required some extra steps because of the mounting on the night tower of the AM array.  Before and after impedance measurements need to be taken on the tower in question.  Another requirement of the CP, a set of before and after monitor points need to be taken.

WBNR tower, with translator antenna side mounted at 390 feet AGL
WBNR tower, with translator antenna side mounted at 381 feet (116 Meters) AGL

While I was measuring the base impedance, I decided measure all the towers instead of just the night time tower that has the translator antenna mounted on it.  This is a good point of reference if any problems arise in the future.  Often, this information can be found in the technical paperwork from the original license application.  Those files can be a treasure trove of information.  Unfortunately, it appears that a good portion of the original paper work is missing.

WBNR tower #1 Antenna Tuning Unit
WBNR tower #1 Antenna Tuning Unit

The Phasor and ATU’s are a late 80’s Harris product.  They are actually in remarkable shape, all things considered.  All of the RF contactors are Harris HS-4P motor driven units.  They are rated at 30 Amps, RF-RMS.  I don’t think that they are supported by GatesAir.  I have a small stock of spare finger stock and contact bars.  I suppose, if I had to, I could make or adapt parts to repair.

Looking at the base currents and the base current ratios for both the day and night patterns (base current ratios are on the station license), the tower impedance has changed very little over thirty years. That is good news, especially with those 215 degree tall night time towers.

The WBNR license application did contain an overall system diagram showing the Phasor and all the ATU’s.  It did not contain any component ID’s or other information.  I scanned that in, created a vector graphics file and expanded it to a 24 x 36 inch size.  I was able to fit all the component values and other information on the diagram.

Schematic diagram WBNR day/night antenna systems
Schematic diagram WBNR day/night antenna systems

The other issue is the monitor point descriptions.  They include statements such as “Point is marked with yellow and white paint on a tree,” or “In the northeast corner of the Texaco research facility parking lot.”  Those references are long gone and I would prefer to use a set of GPS coordinates.  Using the topographical maps from the proofs, I found each monitor point and then recorded a set of GPS coordinates for each.  In the future, they will be much easier to find.  If anyone is still doing monitor points, I would recommend this method.

Yet another problem; the phasor control system was damaged by lightning. The overly complicated Harris Phasor control card was replaced with something a little more straight forward and reliable.   I designed a simple set of relays, one for daytime and one for nighttime, to change the antenna system over.  The transmitter interlock goes through the relay contacts, so the transmitter PDM is killed while the power changes.  Tally back from each of the towers is handled by a set of relays for each pattern, which is also interlocked with the transmitter.  All of this prevents the RF contactors from switching hot, something that has caused some damage in the past.

W243EM is 100 ERP watts, non-directional with a 1 bay Shively 6812-1R antenna installed at 381 feet (116 Meters) AGL on one of the night time towers.

Transmitter is a BW Broadcast TXT-600.  The power calculation is as follows:

ERP 100 Watts = 50 dBm
 
System gains and losses:
 
Transmission Line loss, 500 feet (152.4 Meters), RFS LCF78-50JA =  -1.75 dB
Isocoupler loss, Kintronic ISO-170-FM = -0.8 dB
Antenna gain, Shively 6812-1R = -3.39dB
 
Total system losses and gains: -5.94 dB
 
TPO: 55.94 dB or 393 Watts
 
With all that work completed, the license application was filed to cover the construction permit.  Once that was accepted by the FCC, program test authority was granted and the transmitter was turned on.  Hopefully, with the translator on the air, the perceptions regarding listeners will change and the station can bill more.
 
I really enjoy working on Medium Frequency antenna systems.  I don’t know why, but antenna systems in general are always fascinating to me.