AM BC station categories

[WA3VJB]

I occasionally get queries from people asking how they can track down any retired AM broadcast transmitters that might be available for repair and retuning to our bands.

My general suggestion is to look for the oldest AM stations in the region you're willing to travel, and find those with any history of power authorizations at 1,000 watts and under.  This will include nighttime authorizations as well as earlier daytime levels that might be far lower than what they today can run. 

The result of that criteria then lets you call those stations, ask for the engineer, and wait for a callback. Technical staff these days is most likely on a contract, not fulltime station staff, and they service multiple stations.  Go from there asking about any old transmitters.

I recently came across someone's recounting how the power levels and categories of stations was laid out, with the last major change involving power taking place many years ago (the expanded AM band is substantial change too, but not relevant to old transmitters).

Here are those details.

The master plan for the broadcast band envisioned these classes:

Class I, 10 kW non-directional, initially. Later increased to 50 kW in
the U.S. and Canada. Higher power was permitted in Mexico.

Class II, 0.25 kW to 10 kW non-directional, but limited by any Class I
stations which existed either domestically or internationally, which as
 a
practical matter meant that most Class II stations operated with less
than 10 kW.

Class III, 0.5 kW to 1 kW non-directional, initially. Later increased
 to
5 kW days and 1 kW nights. Still later increased to 5 kW days and
 nights.

Class IV, 0.25 kW, initially, although some were 0.1 kW. Later
 increased
to 1 kW days. Still later increased to 1 kW days and nights.

Now, for regionals on 1460 through 1490, this being pre-1941, those
 were
the so-called "high power regionals" and these stations were permitted
 10
kW non-directional on account of their high frequency. However, these
stations were regionals, none the less, and were not clears.

Every U.S. Class I station, except otherwise stated in Part 73 [ * ] ,
had to employ a directional antenna in order to get to 50 kW nights. I
have previously identified the four exceptions in the U.S. There is
 only
one exception in Canada.

Every U.S. Class III station, with about a dozen or so exceptions, had
 to
employ a directional antenna in order to get to 5 kW nights. And, some
 of
these had to employ a directional antenna in order to get to 5 kW days.

A few U.S. Class IV stations had to employ a directional antenna in
 order
to get to 0.5 kW or 1 kW days. In no case was a Class IV station
permitted to employ a directional antenna at night.

After 1941, the "high powered regionals" were reclassified as Class I-B
 
clears, and while some may have operated 50/10 kW non-directional,
 every
one eventually installed a directional antenna for night operation with
 
50 kW, and two use directional antennas days, while one uses the same
directional antenna days and nights.

[ * ] Here, I am referring specifically to that paragraph of Part 73
which states, "... and on such-and-such kc, one [ Class I ] station
 shall
be permitted ...", as this defines what was a de-facto Class I-A
 station,
before 1941, and what was a Class I-A station in-fact, after 1941.

This paragraph was updated as the list of such stations changed.

These changes occurred, for instance, when KGO and WGY, then both owned
 
by General Electric, and each operating on separate, but immediately
adjacent channels, were combined, with KGO moving to what would become
810, joining WGY there, while that frequency which would become 800 if
KGO had remained a de-facto Class I-A, went to Mexico. This action
 caused
KGO and WGY to become de-facto Class I-Bs, and the U.S. lost a clear
channel in the process.

Other examples would include 680 and what would become 850, when 5 kW
full-time stations were permitted in the East, as regional stations.
Although these particular actions occurred separately, each of these
actions resulted in the stated frequency being removed from the
one-station list, and being placed into the list which states, "... and
 
on such-and-such kc, Class I and Class II stations shall be permitted
..", as this defines what was a de-facto Class I-B station, before
 1941,
and what was a Class I-B station in-fact, after 1941. Of course, any
station on those frequencies which was not a Class I-B, de-facto or
in-fact, was a Class II-B station if operating full-time, or was a
 Class
II-D station if operating LSR to LSS. Those 5 kW stations would later
 be
permitted to increase to 50 kW. Class II-A stations did not exist until
 
1965, and this class, as well as Class I-N, were unique to the U.S.

Another example would include 710, when a 5 kW full-time station was
permitted in the West, as a regional station, and with essentially the
same effect as happened to 680 and 850.

[WB3LEQ]

I sent out about twenty inquiries by either email or the postal service.  Of them I received a total of two replies.  Those replies were both from independently owned stations.  I never did get any replies to date from the corporate owned stations.  I would imagine in todays profit oriented business structures it has now become a high insurance risk to invite someone to a transmitter site with high voltages or possible tripping hazards while having  OSHA standards in place.  It is probably cheaper for them to hire an insured contractor to tear down a transmitter and have the contractor dispose of the components thereby freeing the corporate owners of any liabilities that could become involved.

As I recall I used the following address format when I mailed the inquiries:

W??? Radio
Attn:  Chief Engineer
Street address
City, State  Zipcode

Bob

[WA3VJB]

Bob I hope one or both of those queries pans out.

Personally I find a bit more success making phone calls because you can immediately get a sense of whether the person on the other end grasps the subject.

This also is a better way to pry a response out of the corporate-owned stations, many of which don't know they even have old transmitters in the technical room.

A lot of that hardware has long ago been taken off the inventory sheets, not only because it is fully amortized (written down as an asset) but also through various ownership changes where certain items make it to the conveyance list, and others do not.

Getting the right person on the phone can yield the information and a path to obtaining the transmitter. In such circumstances they may not bring up anything regarding of insurance, OSHA and other liability. They just want the space, and are willing to make it happen.

[Jim, W5JO]

I had an opportunity to talk to the manager of one local area station recently who uses a 500 watt transmitter.  They are preparing a new location because the one they currently use is over 50 years old and the ground system is in sad shape.

I inquired about the transmitter since they are installing a new solid state.  They are trading with some company who takes the old tube type and removes the circuitry and installs the solid state transmitter in the old cablinet.  They offer a trade for the old transmitter on the order of 2-5 percent of the new one depending on age and condition of the present transmitter.

[Jim, W5JO]

I had an opportunity to talk to the manager of one local area station recently who uses a 500 watt transmitter.  They are preparing a new location because the one they currently use is over 50 years old and the ground system is in sad shape.

I inquired about the transmitter since they are installing a new solid state.  They are trading with some company who takes the old tube type and removes the circuitry and installs the solid state transmitter in the old cablinet.  They offer a trade for the old transmitter on the order of 2-5 percent of the new one depending on age and condition of the present transmitter.

That's a new one on me! I've never heard of or seen any of the new SS transmitters that could be installed in one of the old tube type transmitter cabinets. 1-5kw SS AM BC transmitters are usually in standard 19 inch racks these days. Most of the installers won't even take the old AM transmitter for free.

Mack

It was a new one on me as well.  This is the first I have ever heard of doing this.  Most 1KW or less SS types are smaller in total space than the old CV 89 TTY converter I had back in the 70s.

[WA3VJB]

Think of how unlikely it would be for a station to willingly hold that much space for the "new" old rig.

Do they give it back to the same station, or is the idea to then peddle the "conversion" to another station.

In that case, wonder if your station can get its own transmitter handed back to them with solid state innards.

I think it's a scam by some ham radio operator on staff at the transmitter company to claim a purpose for obtaining old station rigs. Not a bad angle, including the traditional sales gimmick of a "trade in" discount, but too easy to check out.

[WA3VJB]

And who would want to go through this twice

Here, the sound of an RCA BTA-1M being uprooted and shoved out the back door of WJRO Glen Burnie Maryland.

Masssive quantities of energy expended.

http://wa3vjb.amham.com/sound/3-Grunt-To-Daylight.mp3

[w4eal]

And who would want to go through this twice

Here, the sound of an RCA BTA-1M being uprooted and shoved out the back door of WJRO Glen Burnie Maryland.

Masssive quantities of energy expended.

http://wa3vjb.amham.com/sound/3-Grunt-To-Daylight.mp3

Hey Paul, did you have to drain the swamp first? Or did you rent a barge?  Hi Hi.

Den

[WA3VJB]

It was pretty dry around there when we visited Denny, I dunno, maybe because of global warning.

We did get the truck stuck out back, it drove fine (empty) up to the door, but when we tried to leave it settled into some soft sandy soil that apparently was where the station used to burn its trash.

A good time had by all.

The worst swamp I ever helped rescue a transmitter from was WUTQ Utica NY, where Steve HUZ picked up a GE BT-20A many years ago. The place was really a dog house, but not for any dog I liked, up on stilts, with gaping holes in the corrugated sheetmetal walls. 

The main transmitter was a very tired Bauer 707, that a guy in Haymarket VA apparently retrieved more recently, according to an article in Electric Radio.  We had to use the truck to drag the GE up a muddy hill to the railroad tracks where we had parked, and then loaded it into the back of the Ryder just before a snowstorm. That, then, delayed our return home by a day.

[flintstone mop]

Hello All,
I had the rare opportunity to talk to a fellow that was sent to a group of stations in Ohio to get them re-organized to make money. He is an on air person and shot gun type engineer with the knowledge of a parts changer until the unit works again.
He talked about an old Western Electric AM transmitter at one of these stations and was oblivious to my asking if it was still in use and that I could use it on the Ham bands if it was retired. He only said that it was the engineering department decision. Corporate owned stations are impsossible to talk to. I'll try some other paths of communications, I guess

Fred