Engineering Radio – Page 5 – One Hundred percent Human Generated Content for your Reading Enjoyment

Marconi would be impressed

I finished up another GatesAir FLX-10 install recently. This one was way out in Provincetown, MA at the end of Cape Cod for WOMR (Outer Most Reaches). That is a community radio station that has an eclectic mix of programs. The studios are on the second floor of an old church.

The transmitter site is located about a mile away from the studios.

A few details on the installation; the antenna is mounted on the water tank, which is the tallest thing around for many miles.

WOMR antenna, Shively 2 bay 6810 mounted on a water tank

The building is less than 120 square feet, which made working a little tight.

WOMR transmitter building, Provincetown, MA

There was very little room outside for the heat exchanger because of the need to get vehicles around the water tank for maintenance. The area around the building was taken up with a generator and HVAC gear. We ended up mounting it to the side of the building horizontally. The main reason was that the wind at this location could come from any direction. If mounted vertically, there was a chance that the wind could blow into the heat exchanger against the fans, possibly causing some overheating problems. Also, the horizontally mounted unit will have a smaller surface area during Hurricanes and Nor’easters.

Heat Exchanger, mounted horizontally on the northeast-facing wall

To do this, I made a unistrut frame and attached it to the outside wall.

The liquid-cooled transmitter takes up much less floor space than the prior transmitter, a Nautel V-10. This installation also included activating an HD Radio signal for this station.

The GatesAir FMXi4G importer/exporter resides at the transmitter site. Currently, the station has HD-1 on the air, no word on any future sub-channels.

Looking North towards the Atlantic Ocean

We had nice weather on one of the days. On the last day (Friday) it was raining with 35 MPH wind guests.

Speaking of Marconi, the US’s first trans-Atlantic wireless transmission station is a few miles down the road in South Wellfleet. Nothing is left of the site; time and erosion have taken all traces away.

Postcard, South Wellfleet Marconi Station

Bronze plaque placed in 1953 by the Wellfleet Historical Society

Here we are standing on the location of the transmitting building. The last two tower bases tumbled over the cliff edge in 2011.

It’s always an enjoyable time installing a liquid-cooled transmitter!

Another LPTV install

We recently put an LPTV on the air in Brookfield, Connecticut. WXGN-LD signed on on Friday, September 6th.

This is UHF station with a 15 KW ERP (the limit for LPTV). This station has an elliptically polarized antenna with 4.5 KW in the vertical polarization.

The transmitter is made by a Spanish company called TRedess

TRedess 4th series 4 amplifier UHF transmitter capable of 3 KW on ATSC 1.0

Dielectric six-pole full-service mask filter

This has been installed in a former Sprint cell building. The wire ladders are left over from them. Still, it makes a convenient place for the mask filter, which is up and out of the way.

I also swept the antenna and filter.

This station is associated with these folks: XGN Network LLC

AM Shut-downs

The big question; how bad is it?

The short answer; Not terrible, not great.

Short summary in a chart:

Service	Licenses Canceled	Licensed and Silent	Comment
Full Power AM	812	105	Since 1991*
Full Power FM	517	88	Since 1991
Low Power FM	502	51	Since 2005
FM translator	1677	138
FM Booster	165	11	Since 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:

Year	Licenses surrendered	States	Comment
1992	1	AR
1993	2	FL, MS
1994	1	GA
1995	0
1996	41	SC, VA, GA, KY, LA, FL, NC, TX, CA, OK, AR, MT, KS, AL, PA, TN, MS, IL, MN, FL, MI, UT, ME, IA	FCC 96-218 rulemaking
1997	33	SC, NY, CT, AR, GA, LA, NJ, AL, VA, FL, ME, AZ, MS, MD, CO, WV, MI, CA, NC, SC, TX, VT	FCC 96-218 rulemaking
1998	9	PA, NC, MO, CA, WV, TX, CT, AL
1999	11	CA, PA, LA, IN, NM, VA, NY, MD, TX, WI
2000	6	FL, CA, VA, WV, PA	Dot-Com crash
2001	12	IA, NC, SC, IA, AR, ND, CA, VA, RI, OK, OH
2002	14	MI, GA, TX, PA, IA, MI, AR, AK, KY, MS, MP (Northern Mariana Islands)
2003	15	CA, AK, MI, PA, MS, ME, CO, GA, KY, AL, CO, VA
2004	34	NC, GA, CO, MS, SC, PR (Puerto Rico), LA, MI, OH, TX, FL, AR, CA, UT
2005	11	TX, GA, CA, AR, IA, PA, MI, OR
2006	16	TX, PA, AR, MI, OR, MS, IL, MN, OK, WA
2007	9	GA, AR, TN, OR, VA, TX, MA, MO
2008	4	FL, MI, PA, AL
2009	7	MI, IL, OK, OR, LA, ID	Sub-prime mortgage crash
2010	7	NY, VA, TX, PA, AL, WV
2011	32	MS, AL, GA, VI (Virgin Islands), MD, MI, AS, TX, AR, IN, FL, TN, SC, NM, IA, NY, PA, LA, VT, NC
2012	25	MS, FL, LA, TX, DE, KY, TN, IN, AL, GA, OH, PA, IL, MS, NC, MI, UT, SC. FL
2013	20	MS, PA, OR, AL, MT, OK, TX, SC, NV, NM, NH, GA, TN
2014	22	SC, CO, AK, AS (American Samoa), IL, AR, PA, RI, GA. IN, MA, MI, TX, NY, MS, WY, AL, MT, VA, LA, MO
2015	21	AR, GA, WI, AL, NE, NV, HI, SC, NY, UT, MO, TN, KY, MA, IL, AR, AL, AK
2016	22	DE, SC, HI, WI, MS, AL, OH, NV, MT, GA, NY, MO
2017	19	NC, KY, CT, MO, GA, IL, TN, WY, NY, CA, OH, NH, PA
2018	18	MD, KY, GA, NC, IL, GA, MS, UT, VA, LA, NY, MT, AR
2019	33	AL, SC, OR, AR, TN, NC, WY, IN, KS, HI, WA, AL, IL, KY, HI, VI, VA, GA, LA, CA
2020	60	MO, 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, NV	Covid-19 crash
2021	46	MI, 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
2022	21	FL, MS, AR, VA, MT, NY, KY, TN, SC, ME, NC, NM, MO, TX, GA, VT, PA
2023	188	TX, 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
2024	35	VA, 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, VT	As 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

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

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

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.

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.

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.

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.

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.