[South Florida DX Association] WLW

[Bill Marx]

WLW's Big-Arse TransmitterHere is something interesting for you to pass 
along to all and enjoy reading, Kappy


WLW

700 kHz.
500 kW.
100% modulation.
no limiter...AM radio used to be different. It was the only thing on the 
air. At night, signals traveled thousands of miles through the noise-free 
sky, and everyone kept a DX log. The FRC/FCC made the 5 kW hayburners leave 
the air at sundown, leaving clear channels for the big guys. The only 
interference was the electric fence in the cattle yard.
If you lived way out on a farm, you probably depended on one or more of 
these distant, clear-channel stations for your only night time contact with 
the world. They were the Class 1-A's, the superstations, the flame throwers. 
They had callsigns like KFI (Farm Information), KOA (King Of Agriculture), 
WSM (We Shield Millions), and KRVN (Rural Voice of Nebraska). There were no 
market areas, no Arbs, no sound-alike syndications, and no graveyard buzz 
from hundreds of close-sited coffee-warmers. AM was bigger stuff than that, 
and Ohio's WLW was the biggest.


 WLW was, and still is, radio engineer heaven. They've been building, 
modifying, and improving equipment since there's been equipment to build, 
modify, and improve. WLW was the 1930s version of NASA, continually testing 
the limits of just what AM broadcasting could do under U.S. regulations.
WLW was originally the extended shadow of Powel Crosley, Jr., yet another of 
those forgotten, 20th century visionaries. He invented things, and sold 
them. Lots of them. Crosley left the high end to other people, preferring 
simple, mass-produced merchandise with extremely attractive prices. It 
worked. He sold refrigerators, auto accessories, and for a time the autos to 
go with them. He sold a lot of them, and made a ton of money. He became 
owner of the Cincinnati Reds, who played in Crosley Field until fairly 
recently, and who still carry their games on WLW.


 Crosley backed into the radio game. In the 1920s, when his son wanted one 
of those newfangled receiver gadgets, Crosley could not believe how 
expensive they were. He decided to build one himself, from directions in a 
book, and for a fraction of the cost. Something clicked in his brain, and 
soon he was selling absolutely astonishing numbers of little radios that 
people could afford.
Crosley Radio really took off after acquiring Precision Instrument Company, 
a manufacturer with an Armstrong license to build super-regenerative sets. 
Crosley's first regens were similar to Precision's Ace, a little, 
battery-powered box with a peep-hole so you could look in and set the 
filament voltage to the single tube by eye. This evolved quickly into the 
ten-dollar Crosley Pup, an even smaller, black cube with the single tube 
poking up on top, knobs to twiddle on three sides. and a "grid leak" on the 
back.

 RCA had its dog, Little Nipper, hearing his master on the phonograph (or 
was it a gramophone?). Crosley had his own little terrier named Bonzo. He 
was shown wearing earphones, seeing as the Pup had no speaker. While Crosley 
came to offer a huge line at all prices and levels of sophistication, he 
continued to make an absolutely incredible amount of money on these little 
sets, breathlessly promoted as "The Armstrong Circuit," even when newer 
designs came in. Crosley certainly knew how to advertise.

Receivers didn't sell without something to receive, so Crosley, like most 
early manufacturers, built a radio station. 8CR, "The Station With A Soul," 
had an 8-foot acoustic horn on the mike. Crosley would stick his head 
halfway into the thing and announce, then someone else would hold a 
gramophone up to the gaping maw. Crosley seemed to like Star of India, so 
he'd play it over and over for hours. No focus groups or format consultants 
for this guy.
Since Crosley Pups, and regenerative radios in general, worked best on 
strong signals, he wanted watts. Lots of watts. He saw to it that his 
stations always had the highest signal strength possible. Not the highest 
practical - the highest possible. He was the champ photon-slinger of 
American broadcasting, and knew it. He liked it that way. You know. It's one 
of those guy things.


 In 1928, WLW was the first U.S. station to make it to 50 kW, courtesy of an 
enormous, water-cooled, Western Electric transmitter, the kind with those 
huge, Frankenstein-ish meters on top and plenty of ominous little windows 
where one could look in and see how hot the tubes were getting. By then, WLW 
occupied the choice frequency of 700 kHz, from a majestic antenna farm near 
Mason, OH, just outside Cincinnati. For several reasons, this was a killer 
site for coverage. When darkness fell, and the band opened up, the mighty 
skip wave from Mason's horizontal antenna ruled the sky.
Now, 50 kW was a hell of a lot of juice in 1932. In an old-style, 
plate-modulated transmitter, it's still a lot of juice in 2000. Crosley, 
though, knew he could do better. Somehow, he finagled the Federal Radio 
Commission into an "experimental" authorization for 500 kW, first with the 
special callsign of W8XO, finally as commercial WLW.
Of course, W8XO really was an experiment, and not a cheap one. Half a 
megawatt, three-quarters fully modulated, millions of peak-envelope watts, 
on 700 kHz, with existing tube electronics, had never been tried. Building 
the beast required the combined engineering talents of RCA, General 
Electric, and Westinghouse. The investment, changed into today's dollars and 
at today's engineering prices, might not have been much less than a space 
mission, which in a way it was.
 GE built most of the modules, but RCA put them together, and gave it the 
historic serial number one. "RCA 1" had a modular design with a lot of 
built-in redundancy, good for when something blew up, which everyone knew it 
would. It used the existing 50 kW, unmodulated in class C, for excitation. 
To this were added three parallel, water-cooled, 167 kW power amplifiers, 
each with four 100 kW RCA 867 tubes, two to a side in push-pull, making for 
12 of these incredibly expensive, five-foot-tall firebottles. Most of this 
height was the anode's copper heat sink, which fit into a pipelike water 
jacket.
The huge, high-level modulator was also water-cooled. It could easily make 
400 kW audio with both of its largely redundant modules simultaneously 
cranked to full rock and roll. Fortunately for the survival of civilization, 
this case was rare. Each module used four more of the biggest tubes made, 
bringing all of RCA 1's RF and AF output tube complement to twenty, with a 
total cost of $34,000 in 1930s' depression dollars. Even more mindboggling 
were the two modulation transformers, one per module, each 37,000 pounds, 
oil filled, and 10 feet high. It's possible that these two Westinghouse 
reactors were in fact the world's largest transformers for a brief time - 
"heavy iron" indeed!

Powel Crosley
throws the big switch B+ and other voltages came from a bank of six huge, 
forced-air cooled, mercury-vapor rectifiers. These 450-amp monsters would 
shake the building's brick walls, not to mention your bones, when they arced 
back. Pure DC, 3000 amps of it, was put on RCA 1's many filaments. This 
awesome juice was homemade, by two large motor-generators, plus a hot 
standby. An early photo shows Crosley, with his left hand in his pocket for 
electrical safety, closing a huge switch to start up one of these. He does 
not look happy.
A new back was built onto WLW's already spacious building, 33 kV AC service 
was brought in, and ultimately RCA 1 grew 15 feet tall, 57 feet wide, and 
something like 30 feet deep. Enclosures weren't so much cabinets as rooms, 
where people might explode if they contacted the wrong circuits. There was a 
catwalk, a balcony really, across the front of the beast, for tube access 
through more of those ominous, glass doors. Under the catwalk were a few 
meters to watch, and a lot of water faucets to turn. Inside, the rig had as 
many Pyrex water pipes as wires. Outside, it looked more like a nuke plant.
RCA 1, then, needed a few features we don't see much anymore. Primary 
cooling water came from a distillery, and was circulated through a heat 
exchanger in the 700-gpm pump room. Secondary water went outside, to a 
fountain-like cooling pond. There were so many relay-driven contactors in 
the Westinghouse control system that they needed another large 
motor-generator for coils and auxiliary circuits. Huge AC transformers, and 
rows of those touch-and-you-die knife switches so popular at the time, were 
everywhere. The whole plant looked a bit like a power station, which to some 
extent it was.

Of course, there had to be a new, vertical antenna, and not just anything 
could do a good job on the expected 70 RF amps at the current loop. Up went 
a beautiful, Blaw-Knox diamond, the strongest and dizziest-looking AM radio 
tower ever designed, reserved for only the elite of broadcasters. You've 
seen pictures of these. They are pointy at the bottom, big in the middle, 
and pointy at the top.
WLW's version was an 800-foot half-wave, guyed in the middle with bridge 
cables. It weighed nearly a million pounds, as much as a small building, and 
in fact it was very briefly one of the world's tallest structures. It all 
bore down to a point, on one giant base insulator with an air-gap lightning 
arrestor. An airplane hit this tower once, barely denting it. It's still the 
primary antenna at WLW, shortened slightly to move a cancellation node out 
of populated areas.
 Needless to say, W8XO's late-night tests went on for months. This wasn't 
your mom's hot plate. When Ohio's famous lightning hit the tower, RF would 
simply sustain any resulting arcs, at the air gap or anywhere else, until 
the carrier was interrupted. There were folk tales, probably accurate, of 
talking rain gutters, sparking fences, singing water pipes, and nearby 
street lights dimming on modulation peaks.
This brings up the real fun part of 1934 AM broadcasting - NO LIMITERS! WLW, 
like any big-time station at the time, gave the Full Monty: 100 per cent 
modulation. Now, radio textbooks always have cute little pictures of sine 
waves at 100%, but people don't talk in sine waves. They don't beat drums, 
play hillbilly music, or yodel in sine waves. If the studio asked the big 
rig for some outrageously asymmetrical upward modulation barely crossing 
zero at all, the DC-sucking beast said FEED ME and obliged - briefly. 
Voltmeters dipped at the power company, antenna current went haywire, cows 
felt funny tingles in odd places, and various shotgun-loud bangs and sparks 
filled the transmitter building.
Operators tried gallantly to ride gain by hand, but this was still not a 
good place to work if you had a fear of electricity. Transmitter logs were 
pretty exciting reading, telling of antenna-house fires, hurried repairs on 
still-dangerous circuits, and rushed replacement of various melted or 
exploded parts.
Eventually, RCA 1 was stable enough for commercial service, or at least as 
stable is it was ever going to get. WLW started giving walking tours of its 
transmitter. Wires were rented, straight to the White House, for a grand 
opening live on the air.
On May 2, 1934, anticipation mounted as Eleanor Roosevelt sang the praises 
of technology and world understanding. Back at WLW, a warning klaxon echoed 
through the buildings, as pumps and generators came up to speed. Outdoors, 
in the pond, water fountains began to spray. In the filament room, bells 
rang as operators zapped those big switches into place. In the contactor 
room, huge relays banged closed. The vast plant came alive. It was ready. 
And then, at 9:30 Central, came the moment of an engineer's lifetime, as 
FDR, the President Of The United States for Chrissake, ceremoniously pressed 
the same golden telegraph key that Wilson had used to open the Panama 
Canal....
 Nothing.
The President and First Lady had forgotten about the transmitter's 
hard-programmed, 30-minute warmup every time B+ was cycled. The great beast 
came on-air, all right, but when it was darn well ready. At long last, 
though, a new signal lit up the air worldwide. It soon became clear that its 
potential night coverage was global, propagation and power supplies 
permitting. Crosley's popular "Moon River" program took one request from 
Buckingham Palace, England!
Engineers later added a manual button to hot-start the transmitter. If the 
tubes were warm, this greatly cut downtime. If the tubes were cold, it cut 
the throat of whichever clown just blew up one of the world's most expensive 
rectifier banks.
WLW's advertising rates jumped 10 dB right along with the signal. The 
station ate money, but it made it faster. Much faster. Everyone wanted to 
pitch half the known world on a superpower, The Nation's Station, Whole 
Lotta Watts, World's Largest Wireless, The Voice From The Sky, the flame 
thrower, the mighty mike heard in London.

Seeing this high-voltage profit potential, fifteen other US stations filed 
for 500 kW. None were authorized. Soon, bitter competitors turned up the 
legal heat on WLW. Crosley couldn't build a cooling pond for that one. Twice 
a year, he and his lawyers would sweat, argue, present, plead, and wheedle 
an ever more hostile FCC into yet another 6-month extension of the 
experimental authorization.
Several stations complained of adjacent-channel interference. WLW briefly 
returned to 50 kW at night, to protect a station in Canada. The solution was 
one of the earliest known anti-skywave phasers. Two towers went up on the 
farm across the street to the north, fed by trolley car wire, to cancel out 
high-angle radiation in that direction. It worked, and WLW resumed full 
power. Too bad Crosley couldn't null out the US media lobby so easily.
In 1938, the US Senate got into the radio consulting business, something 
Congress seems to have done periodically ever since. They passed the Wheeler 
Resolution, "asking" the FCC for an absolute limit of 50 kW. WLW's next 
renewal was denied. After a year of intense court battles, the station 
exhausted all appeals, and shut down the huge amplifiers, except for brief, 
experimental night periods as W8XO. Crosley noted, bitterly, that 50 kW 
wasn't that many more horsepower than a couple of speeding Buicks. (He was 
right, in fact, though it's still an awful lot of RF.) It wouldn't even make 
coffee as far as he was concerned. The law, however, was the law.
Super-power was not the only Crosley project. Another one, starting in 1939, 
was radiofacsimile. This was the "READO" system, using patents licensed from 
Finch Telecommunications. The name presumably meant radio that you read 
instead of heard.
The FCC allowed AM stations to transmit FAX between midnight and six AM. 
Crosley offered a home FAX machine, in a plain woodgrained box, and an 
optional extra timer to turn it on while people slept. Daytime FAX was 
possible too, over stations on the high HF/ low VHF range, with a separate 
receiver and antenna.
This system scanned printing AND photographs on strips of paper just under 5 
inches wide. It used a photocell on a rapidly oscillating arm, deriving sync 
from the AC current. A synchronized arm, again using the AC, recreated the 
pictures on rolls of treated paper in the receiver. The quality was actually 
pretty good, better and more permanent than the first grungy thermal faxes 
sold to consumers for telephone use.
At its peak, something like 13 stations had made arrangements to carry this 
service. It continued on WLW until early in World War II. Crosley also 
advertised a receiver in kit form for hams who wanted to experiment with 
this mode.
In a rather prophetic advertisement, Crosley stated that, "Eventually we 
believe that every home will be equipped to receive sound, facsimile, and 
television." 65 years later, it looks as if we're nearly there.


 "Experimental" W8XO actually did some serious work, greatly improving RCA 
1's power and reliability. By the end of World War II, the beast could 
easily make a megawatt if it had to, and it loafed along at 600 kW. There 
must have been some very interesting nights in Mason. The wartime government 
liked this just fine, considering The Nation's Station an important part of 
the nation's defense, ready to address the whole country at once in an 
emergency. With this as a selling point, WLW filed for a return to 
commercial super-power several more times, right up until the 1960s. It was 
always denied.
We mentioned before that several other stations had filed for super-power 
before the Wheeler Resolution put the lid on at 50 kW. One of these, WJZ in 
New Jersey, had actually ordered a 500 kW RCA transmitter. It was a 
modernized version of WLW's rig, still using 3 PA's in Class C and two 
high-level modulators in Class B, all water cooled. In this case, though, 
the 50 kW exciter was also contained in the transmitter, making for a rather 
awesome row of equipment.
WJZ never got permission to operate this flame thrower, and it remained 
mothballed at the RCA factory. When World War II came, the British 
government bought this transmitter for 112,000 English pounds, no small 
change in 1941. It was modified at the factory for a nominal 600 kW, at that 
time more than WLW/W8XO. The whole thing was then shipped off and installed 
in a huge, underground bunker near Crowborough, UK, where it became part of 
a super-power mediumwave site codenamed "Aspidistra." This was a reference 
to a popular Gracie Fields song, "The Biggest Aspidistra in the World." 
(When "Aspidistra" is not suggesting a part of the human anatomy, it's a 
rather unexceptional house plant with big leaves.)
Aspidistra was also specially re-engineered to be extremely frequency-agile. 
While most super-power mediumwave transmitters required modification and/or 
extensive re-tuning to change frequency, this one could jump all over the 
band at will. Its first task was as a BBC relay that could also be used as a 
jammer, by synchronizing the frequency with German MW stations and 
overpowering their signals.
However, the British Political Warfare Executive ultimately used the 
Aspidistra for "Black" Propaganda, a tactic in which the other side's own 
broadcasts are spoofed in order to gain trust and plant false or subversive 
information. For the remainder of the war, Aspidistra's high power and 
versatility were used extremely cleverly to inject bogus messages to German 
troops or civilians. Some broadcasts were even in Hellschreiber, an 
otherwise exclusively German teleprinting mode which produced hard copy on 
long, thin rolls of yellow paper.
The war also brought considerable change back in Mason, OH. For one thing, 
it got Crosley into the super-power business on short wave. WLW had 
experimented considerably with this mode all through the 30s, first as 
W8XAL, then as WLWU, WLWK, and the historic WLWO. After Pearl Harbor, U.S. 
non-government shortwave broadcasting was closed down, but the Office of War 
Information still saw a need to compete with the huge short wave stations 
being used by the enemy.
Once again, RCA, GE, and Westinghouse were called together. Someone 
mentioned that Crosley Radio had the real smarts both with super-power and 
short wave, and they were invited to the meetings. This was lucky, as it 
turned out. The OWI radio planners asked if anyone thought they could get to 
200 kW, on HF, from six transmitters, by 1944. Crosley Radio, being a 
smaller, more focused company, was the only one that could meet the 
challenge without hurting wartime efficiency in other areas.
Once again, Mason was a great site. It was well back from the coasts, always 
a strategic advantage, and as a bonus it hit all of Latin America with no 
skip zones. At war's end there were five stations there, each with a WLWx 
call, each with a custom-built, Crosley transmitter. Three of these were 200 
kW, one was 50, and WLWO carried on with 75.
Once again, the technical problems were horrendous. New tubes had to be 
designed for 50 kV RF voltages. High-gain rhombic antennas, the standard at 
the time, had to be improved for efficiency, not to mention fire safety. 
Advances had to be made in the fairly arcane art of "re-entrant 
termination," a scheme that let these antennas throw some real juice without 
simply melting. Switching between the resulting acres of carefully aimed and 
tuned rhombics was a nightmare, using open wire lines and long rows of pole 
disconnects that had to be operated by hand in all weather. Birds landing on 
these lines had a tendency to explode, simply vanish into very small pieces.
After the war, these stations became an important part of the US Information 
Agency's Voice Of America. In 1954, VOA moved to a heroic antenna farm in 
Bethany, the next little farm town over. For a very brief time, the Bethany 
complex was the world's most powerful short wave station. The 200 kW 
Crosleys were installed in a formidable row. With their catwalk and glass 
doors, they looked more than a little like good old RCA 1.

Bethany remained a key VOA site, often still using the proud callsign WLWO, 
until the end of the Cold War. Huge Sterba curtain antennas sprouted among 
the rhombics, and rows of giant Collins and Brown-Boveri transmitters 
replaced the old Crosleys.
Unfortunately, the VOA budget was shredded in the mid-90s, and the service 
came under considerable bureaucratic attack. Bethany, which was nearing the 
end of another expensive upgrade, was suddenly shut down, amid a huge 
controversy. Antennas were demolished for scrap, and some of the land was 
sold off to developers. Today, West Chester Township and a veterans' group 
are raising money to restore remaining portions of the site, including the 
old transmitter building and its guard tower, as a museum.
Meanwhile, back at WLW, the engineers weren't exactly sleeping. They kept 
the venerable, 50 kW, 1927 Western Electric going, decade after decade, 
modernizing its insides a number of times. In 1959, though, it got a friend. 
Legendary engineer R. J. Rockwell got Crosley interested in high-fidelity 
AM. They sprung some big bucks for a custom-built "Cathenode" transmitter, 
with a special modulator operating in class AB. This box was flat from 20 to 
20 kHz audio, maximum 1% distortion, fed by one of the world's first 
microwave studio/transmitter links. WLW might not be able to call itself the 
world's largest AM station anymore, but it could sure advertise that it was 
the cleanest.
Crosley invited McIntosh Laboratories, the hi-fi tuner people, to check it 
all over, and indeed WLW was certified as up to state of the art. McIntosh 
noted that the signal actually measured better than several FM stations. 
Obviously, the bandwidth was pretty wide, but nobody complained. Remember 
this the next time someone says AM can't deliver high fidelity!
The rig, though, was understandably very inefficient. When hi-fi AM went 
nowhere, it was converted to the standard class B modulation. It remains 
usable today. Meanwhile, the old WE carried on. It outlasted Crosley Radio 
itself, which was sold to Avco Electronics for a bundle. In 1975, though, 
after almost half a century, it was finally retired for a 50 kW, 
screen-modulated, Continental 317c1, which became the primary transmitter. 
This gave WLW three completely usable 50 kWs.
Today, the mighty Blaw-Knox spits photons from yet another 50 kW, the fourth 
on the site. It's a new, solid-state, class D, all-digital, Harris box, a 
real nice rig, if a bit dull by comparison. It's about the size of a walk-in 
refrigerator, with no external modulator to leak PCB, and it's extremely 
efficient. As always at WLW, we're talking about the state of the art.
 People moan that AM is dead, but nobody's told these guys. 700 WLW, still 
calling itself "The Big One," and "The Nation's Station," remains a 
well-engineered, profitable, class A nondirectional. Engineers have been 
known to live on-site, and a nearby ham has nailed W8XO for his own call.
A custom-built switching system allows instant connection from the primary 
Blaw-Knox, or a recently added backup tower, to any of the four working 
transmitters. Meanwhile, way out of sight in the back of the building, the 
500 kW monster remains amazingly intact. It's in good shape, considering. 
The huge modulation transformers have been drained of PCB, a few parts are a 
bit rusty, and the catwalk is a tempting place to store things. Most of the 
huge tubes, though, are still clamped into place, as if awaiting the cool 
surge of the water and the order again to hurl lightning.
No surprise, then, that WLW saw the year 2000 in right. The chief engineer 
checked everything over, replaced one bad tube, and brought up the 
70-year-old Western Electric. Fed through WLW's Orban audio processor, it 
sounded great. The station went out on it from 10:45 PM local time to 12:15 
AM in the new year. The news announcers found this out, and talked it up. It 
was also noted how much more quietly water-cooled transmitters operate than 
new ones with air blowers......
Radio will survive.