A little bit of catching up…

I regret not having enough time for writing these days. There are a number of reasons for this. Firstly, much of what I do running my business is mundane and not worth noting. For example; today I am going over work reports and reconciling the bank account. Necessary, but about as exciting as watching the grass grow or reading about drying paint.

However, the rest of the time I have been working on various projects around the northeast, to wit:

In Boston, I took part in converting an LPTV station to ATSC 3.0. That was interesting and I am enjoying the TV work.

WCRN-LD exciter GUI
Boris Johnson resigns, also one of the first ATSC 3.0 images transmitted OTA in Boston, MA

In Syracuse, we had to lower a TV transmitter from the 23rd floor to the 22nd floor on the outside of the building. The transmitter itself became marooned because an electrical conduit for an alarm system was installed restricting the size of the stairwell.

Carefully lowering a 2KW UHF TV transmitter, State Tower Building, Syracuse, NY
Transmitter re-assembled and on the air

Fortunately, we hired a moving company to do this. I am pretty sure that our insurance does not cover damages from transmitters falling 22 stories.

In NYC, I installed two FLX-40 transmitters for GatesAir.

WXBK FLX-40 transmitters, Rutherford, NJ
FLX-40 Heat Exchangers
“Do you see over yonder, friend Sancho, thirty or forty hulking giants? I intend to do battle with them and slay them.” “Take care, sir, those over there are not giants but buildings on the island of Manhattan.”

In Kingston, NY a used BE AM1A (along with a coax switch and dummy load) was installed at WKNY.

Slightly used BE AM1A installed as backup at WKNY, Kingston, NY
7/8 inch coax switch and 2.5 KW oil cooled test load suspended from the ceiling

It is nice that this station has a decent backup transmitter to buttress the aging, yet very reliable Nautel ND-1.

Even though it is a short drive away, I had never visited the 1969 Woodstock Music and Art Fair site in Bethel, NY. It was interesting and being sort of an audiophile, I enjoyed this exhibit in particular:

Your author, standing in front of a “Woodstock Bin.”
Back of high-frequency horns

From the display:

This speaker stack sat on scaffolding high in the air… festival sound engineer Bill Hanley custom-built eight speaker cabinets for Woodstock, amplifying music and stage announcements across the large festival site… Afterward, the design would be known in the industry as the “Woodstock Bin.”

Bethal Woods Performing Arts center Museum, August 10, 2022

The high-frequency horns used Electrovoice diaphragm S/A compression drivers. I don’t know which driver was used for the bins.

Site of Woodstock ’69 stage, looking up into the field
Looking down from the field to the stage area. Person(s) for scale.

I am also writing articles for Radio Guide, I hope that you are enjoying them!

Radio Guide; The Magazine

As some of you may have noticed, recently I have been writing some articles for Radio Guide. There are several good reasons for this, but the most important one is education. I believe that terrestrial radio will be around for a few more years. As others have noted, there are fewer and fewer broadcast engineers. Those that understand high power RF and all its intricacies are fewer still. It is important that a cadre of knowledgeable broadcast engineers carry on.

The internet is a great thing. However, it depends on cables of some type to exist. As we know, cables can be damaged. In addition to cables there are routers, core switches, servers and so on. All of that equipment can fail for various reasons. People have been working hard to improve the resiliency of the internet. That is a good cause, to be sure. However small it may be, there is still a chance that the internet can fail. Worse still, this can happen during some type of natural disaster or other emergency. Thus, during such an emergency, Radio can and will function as a vital information source provided that the station is on the air and has a program feed. That is also a good reason to keep the current RF STL paths in place as much as possible.

The Radio Guide articles are a great way to pass along some of that hard earned experience to others. I also want to put supplemental information here for those interested to download. Things like charts, forms, pictures, videos, etc.

What I am planning on is to list the articles here, then put links to any supplemental information provided below that sub heading.

BE AM tuning network

Occasional reader Scott asked for a picture of the inside of a BE AM output tuning network.  I figured it might be helpful to make a short post about it.

These things are pretty simple; a T network with a capacitive leg to ground.

BE AM Output tuning network
BE AM Output tuning network

This particular unit is for 1230 KHz.  I believe the capacitor is frequency determined and they may also use larger inductors for lower frequencies.

BE AM output tuning network schematic
BE AM output tuning network schematic

The inductors are Kintronic LV-15-20 (15uH 20 amp) and the capacitor is 0.0018 uF CDE 6KV 5.6 amp.

The issue with this particular unit is dirt.  The inductors have round metal plates that roll along the inductor coil to make the variable inductor tap.  Dirt has accumulated on the coil turns and on the inside of the plates.  This, in turn, causes arcing anytime the Tune or Load controls are moved.  A through cleaning should take care of the problem.

Status of AM revitalization

It has been about five years since the AM revitalization initiative was first proposed by the FCC and about five years since the first rules changes took place.  Those rules changes included:

  1.  FM translators for AM stations
  2. Allowing stations to use MDCL (Modulation Dependent Carrier Level)
  3. Changing some of the antenna radiation efficiencies requirements
  4. Changing some of the allowable interference towards other stations requirements
  5. Loosening some rules regarding proofs, MOM, night time coverage over city of license, etc

Things that were not addressed:

  1. Receiver quality and technical advances
  2. Ambient noise levels on Medium Frequency (among other) bands
  3. HD Radio or any other digital modulation scheme

Things that were discussed then changed subsequently as a separate initiative:

  1. The main studio rule, which was eliminated for all broadcasting stations

What has been the net effect of these changes?  Has any of this revitalized AM radio?  The net effect has been approximately more of the same.  There have been many stations that have applied for and received licenses for FM translators.  Those stations, in most cases that I am aware of, receive some benefit of extra revenue because of this.  Stations with carrier power levels of 10-50 KW have taken advantage of MDCL technology to save some money on their electric bill.  Nothing wrong with that.

For stations that use a directional antenna, proofs of performance and other DA matters with the FCC have become slightly easier.  Medium Frequency (MF) directional antennas are very large, require a lot of land, are expensive to build, license and maintain.  I know of several stations which have downgraded from a class B station with a directional antenna to a class D station with a single tower and greatly reduced night time power.   Those downgraded stations certainly benefit from an FM translator.

I have heard from more than one AM station owner who says after four years, they are going to “turn in their AM license and just keep the FM.”  I am sure that they are not informed regarding translator rules.  Perhaps, however, the FCC will allow this in the future; a sort of back door commercial low power FM station classification.

The AM band zenith occurred in November of 1991, when there where 4990 licensed AM stations in the United States.  As of June 30, 2018, the total stands at 4633.  That is a decline of 357 stations.  There are currently 90 AM stations listed as silent.  That represents a decline of approximately 9 percent or less than 1/2 of one percent per year.

The last number of AM stations actually transmitting HD Radio that I found was approximately 110, which differs from the iBiquity (and FCC) number of 240.  The FCC data base includes stations which are currently dark, or stations which where transmitting HD Radio at one time but have since turned it off.  Either way, it is a small percentage of licensed stations.  As of this time, AM HD Radio appears to be a non-starter.  In other parts of the world, Medium Frequency DRM seems to be doing well.  The difference seems to be that the DRM operation is all digital and the digital carriers have a much higher power level than that of the hybrid AM HD Radio being used here.

Of those 4633 standard broadcast stations, approximately 260 belong to iHeart radio, Cumulus owns approximately 120 and Townsquare owns approximately 80.   That accounts for 460 stations.  The remaining 4000 or so stations currently on the air are owned by medium sized corporations or individual owners.  The reason for the distinction; I have noticed that the large corporate owners tend to concentrate resources and effort on those licenses that will make the best return, e.g. FM stations.  Of course, there are a few exceptions to that trend, often in major markets.

Of those 4000 or so remaining AM stations, most seem to be treading water.  They are making enough money to stay on the air.  There are a few AM stations that are doing remarkably well.  Those are the ones with primarily  local content.  The vast majority of AM stations are running some type of syndicated talk.  News/talk and sports radio are the two most common formats.  Conservative news/talk seems to be the bread and butter.  Liberal news talk has been tried, but none have succeeded.

Last May, the Supreme Court overturned the Professional and Amateur Sports Protection Act of 1992.  That federal law prevented gambling on outcomes of professional and college sports games.  With the overturn of that rule, individual states can now legalize sports betting.  It will be interesting to see what states allow legalized sports gambling and whether that has any effect on the various sports radio formats.  I can see where individuals and odds makers may want to get good inside information regarding team dynamics and so on.  The sports network that can furnish such information may be in a good position to carve out a niche.

Music can and does sound good on AM when it is done correctly.  There is a great misconception that AM fidelity is poor.  That is not necessarily so.  There are a good many AM receivers these days which have much better bandwidth than the previous generation receivers.  I am noticing that car radios in particular sound much better.  Yes, there are still problems with electrical noise and night time interference.  There are still technological improvements that can be made for analog AM on the receiver side.

In summary; the revitalization efforts have benefited some AM stations in some areas.  The truth is, that many AM stations have been let go for so long that there is no saving them.  Other AM stations that are still viable are making a go of it.  In nautical terms; there is six feet of water in the hold, the pumps are working and the ship is not sinking… for now.