In my never-ending fascination with broadcast transmitters, I bring you the Harris/Gates BC1H. This is an updated model of the BC1G, the main difference being the solid-state audio and oscillator sections in the later H model. This design uses the simple 833 parallel final and 833 push-pull modulator
Sales brochure, click to download the four-page .pdf
Harris/Gates BC1H Transmitter running at 1,000 watts into the antenna. Like many old tube transmitters, this sounds great on the air. The transmitter was made in 1975 and is in backup service. For a 37 year old transmitter, it runs like a champ and comes on consistently. Like the preceding Gates BC-1 models, this transmitter is rugged and reliable. My only comment is the transistors in the solid-state driver section are no longer available. If that were to become an issue, one can always look up the tube audio driver from previous versions (T and H models). It would be a shame to throw away a good transmitter for lack of a couple of transistors, but I know some who have done just that.
This is one of the possibilities that has been bantered about as a solution for the “AM problem.” The theory goes as such; former TV channels 5 and 6 (76 – 88 MHz), which are not suitable for DTV would be an ideal place for the existing AM stations to move. That represents a 12 MHz chunk of spectrum, which is much more than the current 1.16 MHz spectrum the current AM broadcasting service takes up (.54 to 1.7 Mhz). An added benefit is that the VHF spectrum does not have the skywave “problem” that the MF spectrum does, thus many more stations could be licensed to the service. Everyone would benefit, and AM stations would get a new lease on life in the FM band. The number of stations would increase by several fold, including LPFM, non-commercial, and translators. AM stations would no longer be burdened with expensive directional arrays or substandard audio quality.
It seems almost too good to be true…
The FCC reportedly promised “take a hard look” at this idea back in 2008. Four years later, one wonders what has become of it.
A quick search of the existing TV stations licensed to channels 5 and 6 reveals the flaw in this theory. The FCC has re-licensed many full powered and Low Powered DTV stations to channels 5 and 6 since 2008.
List of full power channel 5 stations:
Call Sign
Service
Status
City
State
Fac ID
ERP (kw)
HAAT (m)
Licensee
WOI-DT
DT
LIC
AMES
IA
8661
13.9
566
CAPITAL COMMUNICATIONS COMPANY, INC.
WGVK
DT
LIC
KALAMAZOO
MI
24783
10
169
GRAND VALLEY STATE UNIVERSITY
WBKP
DT
LIC
CALUMET
MI
76001
6.4
301
LAKE SUPERIOR COMMUNITY BROADCASTING CORPORATION
KXLF-TV
DT
LIC
BUTTE
MT
35959
10
588
KXLF COMMUNICATIONS, INC.
KXGN-TV
DT
LIC
GLENDIVE
MT
24287
1
152.4
GLENDIVE BROADCASTING CORP.
KHAS-TV
DT
LIC
HASTINGS
NE
48003
45
217
HOAK MEDIA OF NEBRASKA LICENSE, LLC
WLMB
DT
LIC
TOLEDO
OH
17076
10
155
DOMINION BROADCASTING, INC.
KOBI
DT
LIC
MEDFORD
OR
8260
6.35
823
CALIFORNIA OREGON BROADCASTING, INC.
KIVV-TV
DT
LIC
LEAD
SD
34348
9.2
561
KEVN, INC.
WTVF
DT
LIC
NASHVILLE
TN
36504
22
425
NEWSCHANNEL 5 NETWORK, LLC
WMC-TV
DT
LIC
MEMPHIS
TN
19184
34.5
308
WMC LICENSE SUBSIDIARY, LLC
KCWX
DT
LIC
FREDERICKSBURG
TX
24316
23.7
412
CORRIDOR TELEVISION, L.L.P.
WCYB-TV
DT
LIC
BRISTOL
VA
2455
29.9
743
BLUESTONE LICENSE HOLDINGS INC.
WDTV
DT
LIC
WESTON
WV
70592
10
240
WITHERS BROADCASTING COMPANY OF WEST VIRGINIA
WIWN
DT
LIC
FOND DU LAC
WI
60571
9
338
WWAZ LICENSE, LLC
List of Low Power Channel 5 stations (analog):
Call Sign
Service
Status
City
State
Fac ID
ERP (kw)
HAAT (m)
Licensee
KSCT-LP
TX
LIC
SITKA
AK
15348
0.049
0
DAN ETULAIN
K05KF
TX
LIC
DILLINGHAM
AK
792
0.16
0
ALASKA CORP OF SEVENTH DAY ADVENTIST
KRDN-LP
TX
LIC
REDDING
CA
127179
0.6
0
KM COMMUNICATIONS, INC.
W05CO
TX
LIC
SARASOTA
FL
66995
3
0
THREE ANGELS BROADCASTING NETWORK, INC.
W05CJ
TX
LIC
KEY WEST
FL
125642
0.59
0
JAMES J. CHLADEK
DKHHB-LP
TX
LIC
HILO
HI
126233
3
0
KHHB, LLC
WIKY-LP
TX
LIC
EVANSVILLE, ETC.
IN
61036
0.14
0
ROBERTS BROADCASTING COMPANY OF EVANSVILLE, IN, LLC
Looking through this data, particularly the digital licenses which were granted since 2009, one an only assume that the FCC has, by de facto, nixed this idea if it ever considered it at all.
There has been lots of hand wringing and ink spilled regarding the sorry state of affairs in the senior service. AM is plagued with problems; interference, poor bandwidth, etc. To that end, the NAB has launched studies and initiatives and hired all sorts of pricey consultants to consult with. Here is my own AM improvement plan and it is rather simple:
Clean up the transmitter site.
Get rid of AM HD radio.
Variable IF bandwidth receivers.
Improve Programming.
How many of us have seen AM transmitter site dumps? Deferred maintenance, malfunctioning directional arrays, trees growing up on the ground system, flooded buildings and ATU’s, rusty towers, transmitters not a full power, ground system deteriorated or missing all together, just to list a few problems. Many AM transmitter sites are technical disasters. Think that these things have no bearing on the AM station’s signal? Think again.
Differed maintenance, AM transmitter site (there is a tower in there somewhere)
Trees growing around the tower base can attenuate the signal by 30%. A comment from a well known engineering firm:
…Recently XXX field engineers had occasion to measure an AM station at XXXX kHz before and after removing vegetation in the vicinity. The station had a quarter-wave tower. The base area had grown up in brush and hardwood trees to a height of perhaps 30 feet (9m) and this extended from near the base across the entire ground system. After clearing (cutting, no ground system disturbance), the signal measured at some 16 locations on four radials went up a uniform amount of about 15% or 1.2 DB. That’s about a 30% increase in radiated power…
That is an inexpensive power boost and they didn’t even have to file with the FCC! A 1 – 2 dB power gain is pretty nice and can mean the difference between a listenable signal and static. How many times have I heard the lament that AM band is full of noise and not listenable. Certainly, there are major challenges in the urban listening environment. Putting forth a better signal will overcome some of this electrical noise.
There is a reason why engineering standards were developed for the physical plant; they work.
There is no cure for the noise that AM HD Radio puts out into the adjacent channels. This self interference benefits none, not even the station transmitting AM HD Radio. This dubious technology has proved itself a non-starter and should be discontinued. For smaller station owners, the cost of implementing AM HD Radio is prohibitive. Licensing of a proprietary modulation scheme, new transmitting equipment, specialized exciters plus any needed bandwidth improvements to AM antenna arrays can easily exceed $100,000.00. Unfortunately, it is often the small AM radio operators that are making a good showing, and serving their community of license and making money. These are the very stations that are hurt the most by adjacent channel AM HD Radio interference.
Receiver design over the last twenty to thirty years has been the greater issue with perceived low AM broadcast quality. AM receivers have an average bandwidth of just 3-4 KHz, which is slightly better than telephone quality. AM broadcasting has gotten a bad wrap because of this and there are many comments about how AM is “inferior quality” to FM. With a quality older receiver, AM can sound very good. Of course, the receiver manufactures all point adjacent channel interference as their rational for reducing IF bandwidth. Why not leave it in the hands of the user? The GE Superradio had this feature with a “wide” and “narrow” setting for AM reception. They worked remarkably well. A receiver could also be designed to automatically increase IF bandwidth at higher received signal strengths.
Finally, as the saying goes; Garbage in, Garbage out (GIGO). This holds true for many things including radio programming. Expecting that mediocre satellite syndicated news talk will garner great ratings and huge revenues is silly. For years and years, station owners have put minimal effort into AM radio and expected big returns. It is not working. AM stations that go against that trend; those with unique formats (Gasp! Music, on AM?), local content, and community oriented programming can and do succeed. They are fighting an up hill battle in both directions. With all of the business pressures from larger broadcast groups, interference issues and negative viewpoint on the viability of the AM band, one wonders how long they can last.
My first job as Chief Engineer was at WPTR and WFLY in 1991. I was young and it was a learning experience. The WPTR transmitter was a Harris MW50A, which reliably went off the air every six months. The transmission lines going out to the towers had fallen off of their wooden support posts, trees were growing up in the antenna field, and sample lines were going bad. In short, it was a mess. Even so, the station was well-known and well-liked in the community. One could still see echoes of greatness that once was.
When Crawford Broadcasting purchased the station in 1996, they put much money and effort into renovating the facility. Replacing the Harris transmitter with a solid state Nautel, replacing the phasor and transmission lines, cutting the trees from the field, painting the towers, renovating the old transmitter building into a new studio facility, and finally removing the old Butler building that formerly housed the “Gold Studios.”
Then the depression of 2008-20?? hit. Once again, the place has fallen on hard times. WDCD-AM has been silent since last April. The cost of running the 50 KW AM transmitter being too much to bear in the current economy. Formatically, the station drifted around for several years. According to the STA to go silent:
WDCD WILL SUSPEND OPERATIONS FOR A PERIOD DURING WHICH IT WILL DEVELOP AND PREPARE TO DEPLOY A NEW PROGRAM FORMAT AND REPOSITION ITS VOICE AND IDENTITY IN THE COMMUNITY.
They may need to do something slightly non-religious to survive.
While we were waiting for the utility company to turn the electricity back on after yesterday’s fire, I took a short walk around the WDCD-AM site and took some pictures. The transmitter disconnect thrown, fuses are pulled, it is kind of sad to see the Nautel XL-60 dark:
Nautel XL-60 AM transmitter. WDCD Albany, NY
I apologize greatly for the blurry picture, it was taken with my cellphone camera, my good camera being back at home on my desk. Radio stations, when they are on the air, seem like they are alive. Machinery hums, fans move air, meters move, and there is a sense of purpose. Silent radio stations give me a sense of foreboding like something is terribly wrong.
WDCD three tower array, Albany, NY
View of the towers without Butler Building. The towers are 340 feet tall, which is 206 electrical degrees on 1540 KHz. The site was constructed like this to suppress skywave signals toward ZNS, Nassau, Bahamas. ZNS is the only clear channel station allotted to the Bahamas by NARBA. The other station WDCD is protecting is KXEL, Waterloo, IA. During the 90’s, I received many QSL requests from Norway/Finland and even a few from South Africa. I know that the station had a large following in most of New England.
WDCD tower base, tower one (furthest from building)
Tower one tower base. This IDECO tower had to have the top 60 feet replaced after it was hit by an airplane in 1953. The tower base also had to be replaced in the late 1980’s as it was crumbling and falling apart. To do this, Northeast Towers used railroad jacks and jacked the entire tower up off of the base insulator. They re-formed and poured a new base, carefully letting the tower back down on a new base insulator about a week later.
WDCD towers looking back toward the transmitter building
Antenna field looking back at the transmitter building. If you work at radio transmitter sites, I encourage you to take pictures of all these things, as someday, they will all be gone.
WDCD bomb shelter
The “bomb shelter” and 220 KW backup generator, constructed by FEMA in 1968 as part of the BSEPP. This used to have an emergency studio and enough diesel fuel for fourteen days of operation. Now, the bomb shelter has a kitchen and bathrooms. The underground storage tank no longer meets EPA standards and has been pumped out.
WDCD Onan generator
The Onan generator is conservatively rated at 220 KW, surge rating 275 KW. These things were way over-constructed, so it is likely it would easily run 225 KW all day. It has an inline six-cylinder engine with a massive flywheel. When the engine is stopped, it takes about twenty seconds for the generator to stop turning.
Three phase service
National Grid, 3 pot, 480 volt, 3 phase service, original to the 1947 building.
