American Medium Wave Radio on High Power
On two previous occasions here in
Wavescan we have presented the story of high powered broadcasting; on longwave
throughout the world, and on medium wave throughout the world except for North
America. On this occasion we present the
story of high powered radio broadcasting on medium wave in the United States,
Mexico and Canada under the title ”Another Blast from the Past American
Medium wave Radio on High Power”.
As in other parts of the world, when
medium wave radio broadcasting made its first tenuous attempts in the United
States, the transmitter power was quite low, some times as low as 5 or 10
watts, with 500 watts considered to be in the top bracket. The first station in the United States at 5
kW was Powell Crosley’s famous WLW in Cincinnati Ohio which
was inaugurated in January 1925 on 710 kHz at a new location in Harrison Ohio.
Even
though WLW became quite famous in the American power race, yet it was not the
first station to operate at a higher power level. Towards the end of the year 1925,
Westinghouse opened a new facility at Bound Brook for their medium wave station
WJZ which was licensed at the time to Newark New Jersey.
This new WJZ transmitter was rated
at 50 kW (on 660 kHz) and it is listed as the first station in the United
States at this power level. However, the
strong signal from the new WJZ overwhelmed everything else on the air and so
this higher power was in use only spasmodically for the first ten years.
Three years after the inauguration
of WJZ at a spasmodic 50 kW, the Cincinnati WLW inaugurated its 50 kW unit at a
new location in Mason Ohio, somewhat north of Cincinnati itself. This was the first medium wave station with
regular operation at 50 kW in the United States, and several other stations
followed in quick succession.
The first super power station in the
United States was not WLW, and not even KDKA, but rather WGY at South
Schenectady in New York State.
According to Radio Broadcast
magazine for October 1927, station WGY was permitted to conduct test broadcasts
at 100 kW from midnight until 1:00 am under the callsign W2XAG. These high powered test transmissions began
on August 4, 1926, and a photo of the transmitter is shown on page 340 of this
particular issue of Radio Broadcast magazine.
At an increased power of 200 kW, W2XAG began another series of test
transmissions on March 9, 1930.
Then came the well known KDKA at
Pittsburgh in Pennsylvania. In the early
part of the year 1932, the famous KDKA began experimental transmissions at 400
kW from its location at Saxonburg under the callsign W8XAR. These experimental broadcasts were permitted
on air only between 1:00 am and 6:00 am.
Nearly
two years later, WLW began test transmissions from its new 500 kW transmitter
under the callsign W8XO. This massive
transmitter was assembled under contract by RCA at their Camden factory in New
Jersey.
Both GE and Westinghouse participated
as sub-contractors for the Ohio project by providing basic segments for the
total transmitter assembly which was made up of a 50 kW transmitter acting as
the driver followed by three successive power amplifiers. The entire transmitter was installed against
the back wall of a second building at Mason Ohio, adjacent to the regular
transmitter for mediumwave WLW. The
entire facility, transmitter and antenna system, cost $½ million
and it was inaugurated on May 2, 1934 during a ceremony at the White House with
President Franklin D. Roosevelt.
However, because of the massive
power output from Mason Ohio, complaints flooded in from listeners in both
Canada and the United States who complained of interference to programming from
other stations on the same or nearby channels.
People living nearby to the massive transmitter complained that the
programming could be heard from metal roofing, coil springs in mattresses and
from other spots at the conjunction of two different metals. In response, the power output from WLW-W8XO
was reduced to just 50 kW during the hours of darkness.
During World War 2, the 500 kW W8XO
was switched into service for occasional special broadcasts for American
servicemen on duty in Europe. The last
time that W8XO was on the air with programming at full power was in 1943,
though the transmitter was maintained for possible usage up into the
1960s. Sometime afterwards, the
transmitter was gutted leaving just the shell, and the antenna system was sold
to an FM station in Eaton Ohio, station WCTM (WJAI-WGTZ) 92.9 MHz.
During the era running from the
1930s into the 1960s, somewhere around twenty medium wave stations in the United
States applied to the FCC for approval to install super power transmitters and
the requested power level varied from 400 kW to 750 kW. However, none were approved and the maximum
power level for medium wave in the United States (and Canada also) has remained
at 50 kW.
The first high powered medium wave
transmitters in Canada were 50 kW units that were installed for coverage of
Toronto and Montreal in 1937. The new
CBL Toronto was built at nearby Hornby and it was allocated the channel 740
kHz; the new CBF Montreal was
built at nearby Contrecoeur and it was allocated the channel 910 kHz.
Interestingly, Mexico also entered
the power race back in the 1930s with a whole slew of stations in northern
Mexico that were bent on capturing listeners across the border in the United
States,
a lucrative commercial market. These
border blasters as they were called, emitted power ranging from 50 kW, up to
100 kW and 250 kW, and even 500 kW.
Station XED in Reynosa was the first
border blaster in Mexico at 10 kW in 1930.
This station later became XEAW.
It appears that the highest powered border blasters in Mexico have been
XERA at Villa Acuna, and XEX & XEW in Mexico City, each at around 500 kW.
The current WRTVHB lists just seven
super power mediumwave stations in Mexico.
These are:- One station at 78 kW XEWW Tijuana 690 kHz
Four at 100 kW XEG Monterrey 1050
XEP Mexico City 1060
XERED Mexico City 1110
XERF Cuidad Acuna 1570
One at 150 kW XEWA San
Luis Potosi 540
One at 250 kW XEWW Mexico
City 900
In
the United States itself, four super power stations have been constructed and
taken into regular radio broadcasting service.
The first on air was WGY-W2XAG at South Schenectady in New York State
with 100 kW in 1926 and 200 kW in 1930
The second superpower station was KDKA-W8XAR at Saxonburg in
Pennsylvania with 400 kW on 980 kHz in 1932.
The third was WLW-W8XO in Mason Ohio with 500 kW on 700 kHz in 1934.
The fourth American superpower
station was WJZ in Bound Brook New Jersey with 500 kW on 770 kHz. However, this WJZ super power transmitter was
never activated at Bound Brook in the United States; instead it was exported to
England for another purpose, and that’s another story for another day here
in Wavescan.
(AWR-Wavescan/NWS 289)
