AM Shut-downs

The big question; how bad is it?

The short answer; Not terrible, not great.

Short summary in a chart:

ServiceLicenses CanceledLicensed and SilentComment
Full Power AM812105Since 1991*
Full Power FM51788Since 1991
Low Power FM50251Since 2005
FM translator1677138
FM Booster16511Since 1991
Summary of silent and canceled licenses

*1991 was the peak number of AM licenses. It also marks when the FCC record-keeping began tracking the license status of all services.

There are 10,846 full-power FM stations, 8,374 FM Translators, 1,910 Low-Power FM stations, and 373 FM boosters currently licensed as of this writing.

According to the FCC data, the peak number of AM stations occurred at the end of 1991 with a total of 4,985. As of August 2024, there are 4,303 stations. There are 105 AM stations licensed and silent.

AM station licenses are being surrendered to the FCC at an increasing rate in the post-Covid era. I like charts. It is fun to look at raw data sorted in different ways. Fortunately, the FCC’s license management system allows one to search for various categories e.g. “Full Power AM” and “License Cancelled.”

Here is a chart by year of the number of AM station licenses surrendered to the FCC:

YearLicenses surrenderedStatesComment
19921AR
19932FL, MS
19941GA
19950

199641SC, VA, GA, KY, LA, FL, NC, TX, CA, OK, AR, MT, KS, AL, PA, TN, MS, IL, MN, FL, MI, UT, ME, IAFCC 96-218 rulemaking
199733SC, NY, CT, AR, GA, LA, NJ, AL, VA, FL, ME, AZ, MS, MD, CO, WV, MI, CA, NC, SC, TX, VTFCC 96-218 rulemaking
19989PA, NC, MO, CA, WV, TX, CT, AL
199911CA, PA, LA, IN, NM, VA, NY, MD, TX, WI
20006FL, CA, VA, WV, PADot-Com crash
200112IA, NC, SC, IA, AR, ND, CA, VA, RI, OK, OH
200214MI, GA, TX, PA, IA, MI, AR, AK, KY, MS, MP (Northern Mariana Islands)
200315CA, AK, MI, PA, MS, ME, CO, GA, KY, AL, CO, VA
200434NC, GA, CO, MS, SC, PR (Puerto Rico), LA, MI, OH, TX, FL, AR, CA, UT
200511TX, GA, CA, AR, IA, PA, MI, OR
200616TX, PA, AR, MI, OR, MS, IL, MN, OK, WA
20079GA, AR, TN, OR, VA, TX, MA, MO
20084FL, MI, PA, AL
20097MI, IL, OK, OR, LA, IDSub-prime mortgage crash
20107NY, VA, TX, PA, AL, WV
201132MS, AL, GA, VI (Virgin Islands), MD, MI, AS, TX, AR, IN, FL, TN, SC, NM, IA, NY, PA, LA, VT, NC
201225MS, FL, LA, TX, DE, KY, TN, IN, AL, GA, OH, PA, IL, MS, NC, MI, UT, SC. FL
201320MS, PA, OR, AL, MT, OK, TX, SC, NV, NM, NH, GA, TN
201422SC, CO, AK, AS (American Samoa), IL, AR, PA, RI, GA. IN, MA, MI, TX, NY, MS, WY, AL, MT, VA, LA, MO
201521AR, GA, WI, AL, NE, NV, HI, SC, NY, UT, MO, TN, KY, MA, IL, AR, AL, AK
201622DE, SC, HI, WI, MS, AL, OH, NV, MT, GA, NY, MO
201719NC, KY, CT, MO, GA, IL, TN, WY, NY, CA, OH, NH, PA
201818MD, KY, GA, NC, IL, GA, MS, UT, VA, LA, NY, MT, AR
201933AL, SC, OR, AR, TN, NC, WY, IN, KS, HI, WA, AL, IL, KY, HI, VI, VA, GA, LA, CA
202060MO, NE, FL, GA, LA, ID, TX, MP, AR, AK, KY, IL, AL, NJ, TN, MI, SD, MS, VA, CO, OH, SC, NM, WI, ND, AZ, OR, MD, PA, NVCovid-19 crash
202146MI, FL, AL, NV, GA, NM, PA, AZ, IN, OH, TX, IA, OR, CA, VA, IL, TX, TN, CA, NC, LA, OR, AZ, MS, SC, WV, WA, PA
202221FL, MS, AR, VA, MT, NY, KY, TN, SC, ME, NC, NM, MO, TX, GA, VT, PA
2023188TX, SC, MI, CA, ID, IL, OR, MD, MA, NM, AR, FL, KY, OH, TN, NC, LA, AR, CO, ME, MS, GA, WA, MI, OH, PA, VA, NJ, WI, NY, HI, NH, UT, IN, MT, SC, WV, IN, GU (Guam)The Great Cancellation of May 4, 2023
202435VA, AL, ME, LA, NC, MO, NY, SC, AZ, IL, NM, NV, WA, FL, TX, IN, WY, WA, KS, CA, MA, OH, NJ, AR, GA, CO, PA, VTAs of August 2024
US AM station cancelled licenses since 1992

A couple of things to note; there seems to be a two-year lag between any major economic downturn and a mass surrender of licenses. Covid-19 appears to be the exception. When the shutdowns came, clients canceled their advertising in mass causing a rapid end of already teetering businesses. In 1996, the FCC changed the rules on silent stations, limiting the time allowed to be silent to 12 months, after which the station license was canceled.

In 2023, the FCC performed a bit of housekeeping, canceling 188 AM expired station licenses some of which had been expired for decades. They performed the same thing for the FM band in October.

While every state and territory has at least one surrendered license, some states have more than average. Those tend to be mostly in the south; Alabama, Louisiana, Georgia, Florida, Mississippi, South Carolina, and Kentucky.

differed maintenance, AM transmitter site
differed maintenance, AM transmitter site

Too many AM stations these days are dead men walking. It takes effort to keep an AM station on the air. Maintenance of antenna arrays, particularly directional systems, is expensive. Selling advertising is much more difficult than it is for FM stations. Local programming is expensive. The land under an AM tower is often worth more than the license itself.

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

Land within certain city limits is a ripe target for developers. As more pressure mounts on station owners (taxes, zoning, etc) how long can they last before the inevitable happens?

Then there is the aging audience problem and in many smaller operations, the aging owners problem too.

The transition to digital modulation never happened. There are no AM stations running hybrid (MA1) HD radio. There are three AM stations that I know of that are running the all-digital (MA3) version of HD Radio.

In spite of those things, AM continues on.

Perhaps one reason; AM equipment is fairly simple in design and ease of use. Take away the electrical noise problem and it works well. AM radios are still ubiquitous in most houses, cars, hotel rooms, etc.

Many AM stations now have an FM translator, which is especially helpful if the AM station has to sign off at sunset or greatly reduce power. Some AM stations are simulcasting with full-power FM stations.

Crossed Field Antenna, Courtesy of Wikipedia
Crossed Field Antenna, Courtesy of Wikipedia

Are there any technological developments that would solve some of the issues facing AM broadcasters? More economical yet still efficient antenna designs that save space? A different modulation scheme that is still compatible with full-carrier AM and will work with older receivers (9K5R3E)?

Those question will likely remain unanswered. The FCC has shown no interest in allowing experimentation on the Medium Frequency band.

Fordham University WFUV

Over the last several months, I have been helping out in a small way with WFUV’s new transmitter installation. George Evans, CE for WFUV, and Bill Weeks of Wolftron Electronics did most of the work. This project’s location is unique; the transmitter is in an equipment shelter on top of the Montefiore Medical Center in the Bronx. That complicated the removal of the old transmitters and installation of the new transmitters.

WFUV tower atop the Montefiore Medical Center

This is the top of the Montefiore Medical Center in the Bronx. The building has 28 floors. To access the transmitter, one needs to go up another flight of stairs to the roof. Go outside onto the roof and take two more flights of stairs to the transmitter shelter just below the tower. Those stairs can be seen as a thin wispy thing on the left of the elevator building.

WFUV tower, close up

At the top of the tower, the two-bay Shively antenna is for WVBN 103.9 Mhz. WFUV 90.7 MHz is the six-bay Shively just below that.

BE FMi 703 (FM-10S)

These are the transmitters being replaced. There are two of them running combined for a TPO of 14.2 KW (including the -14 dBc HD subcarriers). They are about 20 years old.

The before picture; combined BE FMi 703 transmitters

As you can see, there is little room to work in this space. The old transmitters needed to be removed from the room, hosted down two stories to the main rooftop, wheeled around to the door, and then lowered another flight of stairs to the 28th to the elevator.

It makes me tired just thinking about it.

BE FMi 703 (less RF modules and power supplies) being lowered to the rooftop level

Out with the old, in with the new.

GatesAir FAX15K being hoisted from the roof up to the transmitter shelter

The GatesAir FAX15Ks made the trip up safely. Able Rigging from New Jersey did all of the moving into and out of the shelter. The two transmitter chassis, all of the boxes containing the exciters, RF modules, power supplies plus a 25 KW dummy load, and the cut-up for scrap Myat variable T antenna combiner were removed in one go.

The after picture; GatesAir FAX15K transmitters, two cabinet version

The FAX15K’s are in the shorter cabinets (requires two) because the taller cabinet would not fit in the elevator.

FAX15K with back doors removed, power block, combiner, directional coupler, and RF output flange.
3-inch coax switch and RF plumbing

The output of each transmitter goes to a 3-inch coax switch. The bottom port of the switch goes to the Shively filter (thence to the antenna), and the top port goes to the 20 KW dummy load.

3-inch coax switch
Bill Weeks routing control wiring to coax switch
WFUV CE George Evans, heading to the job site
“How many more times do I have to climb these stairs today?”
But the view is great! Mid and upper Manhattan in the distance
Your author is about to tell a sea story…

I enjoyed working on this project.

The Green Bank Telescope (GBT)

One of the nice things about taking a small vacation is that I get to do some of the things that I like to do. We went on a brief road trip to eastern West Virginia recently and that area is beautiful almost beyond description. We spent several days staying at various state parks, enjoying the hiking and history of the area.

Then there is this:

The backside of the Green Bank Telescope (GBT)

That huge thing poking up from a fairly remote valley is the Robert C. Byrd Green Bank Telescope. According to their website, it is an off-center fed steerable dish with a 100-meter diameter collecting area. The surface accuracy provides excellent sensitivity within the 290 MHz to 118 GHz operating frequency range. It has a 61-meter (200-foot) feed arm, making the entire structure 148 meters (485 feet) tall.

The dish reflector area is a 100 x 110 meter (330 x 362 foot) section of a 208-meter (682 foot) diameter symmetric paraboloid. The surface area consists of 2209 solid aluminum panels, each with its own actuator to adjust the surface and compensate for gravity, which distorts the paraboloid differently depending on the elevation angle. Maximum distortion occurs in the full horizontal (bird bath) and the maximum vertical elevations. The surface accuracy is better than 50 micrometers, allowing for efficient operation into the 118 GHz region. The total collection area is 9,300 square meters or 2.3 acres. As they say, “We could detect a cellphone in airplane mode on Saturn.”

In other words, it is large.

Your author, chatting with Mike from Troy NY about motorcycle camping

The Green Bank Observatory is located in the Nation Radio Quiet Zone which stratles the WV/VA border. The area within a 10-mile diameter of the GBT is closely monitored and regulated. Even WiFi at the nearby Green Bank public library is not available. All of the computer networks in the facility are cabled Ethernet. There are no broadcast stations and cell towers are very restricted.

National Radio Quite Zone boundaries

One bonus for going on vacation in the National Radio Quiet Zone; no phone calls, text messages, or annoying email alerts while out enjoying the natural beauty of the area. A vacation without interruption is truly relaxing.

Green Bank Observatory

The Green Bank Observatory has several other radio telescopes on site researching several areas. The original Reber Radio Telescope (named after its builder, Grote Reber) is displayed by the visitors center. The Reber Telescope is considered the first radio telescope purposefully constructed and it dates from 1937.

Reber Radio Telescope display

If you are interested in science, technical stuff, or just like to go stare at giant receive dishes, I highly recommend a visit.

Generator Replacement

This Onan 30OEK propane-powered generator has been in service for 39 years at a transmitter site where the power goes out often. It has a lot of hours on it. The hour meter stopped working about 15 years ago, but the hours back then were 1097.

In addition, the main shaft seal started leaking oil about 10 years ago, creating an oily blowback mess every time the generator ran for more than a few hours. The block heater went bad, the battery charger overcharged then exploded the battery splashing sulfuric acid all over the housing and engine block.

The last power outage was the final one. It ran for a few hours then faulted. When the local engineer tried to restart it, it was never able to get to speed and was misfiring badly. Below appeared a large and spreading puddle of engine oil.

As this station is one of the major money makers for the owner, a replacement generator was obtained.

Cummins RS50 50 KW Propane powered generator

This is larger than the old generator. The good news; now the AC can be put on the generator to keep the room cool. In the past, the backup cooling fan was used when on generator power, which sucked dirt, bugs, and pollen into the room.

It will also have considerable headroom for any additional loads that may be installed in the future.

The generator in place and leveled

We had to enlarge the opening for the radiator and put in some steel angle for the lintels.

Exhaust piped outside with the radiator air

The first start run and load test went well. I ran it for about 30 minutes under full load, enough time to burn the paint off the exhaust manifold. Seems like a pretty solid unit. With the power conditions at this site, it will get a lot of use.