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Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while typing up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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Operation Radio Airwatch
1959 Popular Electronics
a $50,000 helicopter! You can't touch a new heli these days for
less than a quarter of a million dollars (Robinson
R22). 1959 marked the early days of helicopter traffic reports,
I'm guessing before the good noise cancellation headsets so drivers
down in the traffic snarl tuned in their AM radios and got a lot
of reporters yelling in to the microphone to overcome the rotor
chop-chop-chop noise in the background. An airborne GE unit transmitted
3 watts at 26.19 mc (MHz), and received on a triple conversion,
crystal-controlled receiver. If you look at the one photo, you'll
see a Handie-Talkie on the passenger seat.
July 1959 Popular Electronics
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
See all articles
Operation Radio Airwatch
By Morris Moses
Radio-equipped helicopter spots
Los Angeles Freeway traffic snarls
of electronic and radio communication equipment, a colorful helicopter
prowls above the traffic-congested freeway system in Los Angeles,
California. The roving whirlybird seems to be everywhere at once,
knows in an instant when safety is threatened below, and shares
this knowledge with some three million harassed drivers faster than
you can say, "turn off at the nearest intersection."
call six days a week, 24 hours a day if need be, the trim $50,000
Bell 47-H flies pilot Max Schumacher and newscaster Donn Reed 500
to 2500 feet above the jammed freeway system. Hovering at a standstill,
or cruising at 80 miles per hour, the "Operation Airwatch" team
transmits reports on traffic conditions to Radio Station KABC which
re-transmits these messages on its regular assigned frequency, 790
kc. The driving public keeps its auto radios tuned to KABC for the
latest traffic information.
Once Max and Donn spotted a little girl innocently playing with
a ball right in the middle of whizzing traffic on the Los Angeles
Harbor Freeway. Donn got on the air in about two seconds, and blurted
out a warning to the Harbor Freeway traffic. Minutes later, police
arrived and bundled the little girl off to their lost-and-found
The cockpit of the radio-equipped helicopter. Control box can
be seen mounted between two portable receivers. The standby
"Handie-Talkie" is kept on the seat.
Pilot Max Schumacher and announcer Donn Reed on the job.
Ingenious Equipment. Engineers
and technicians at KABC wanted a minimum of controls and switches
on the 'copter. Simplicity, economy, and reliability were the technical
watchwords. Even though most of the equipment is of commercial origin,
there is a feeling of radio ham ingenuity and even "homemade" simplicity
about the installation.
The link between the 'copter and
Station KABC is a commercial General Electric 15-watt FM transmitter
and receiver. Units are identical at both the fixed and mobile stations,
with the exception of power supplies. The base station is a.c.-powered
and the equipment on the 'copter is powered from its 24-volt d.c.
supply. The receiver is a G.E. superheterodyne using a triple-conversion
circuit, with each converter employing a separate crystal-controlled
Air Rescues. Police radio calls are monitored
with the aid of a converted RCA transistorized broadcast receiver.
In between routine traffic guidance, the busy whirlybird has followed
the police calls to some very unusual air-rescue adventures.
When three teenage boys and a rubber life raft were mixing it
up with the Los Angeles River, pilot Max swooped down on the youths
and helped push them ashore with a blast from the whirlybird's rotors.
Meanwhile announcer Donn gave the radio audience below a spray-by-spray
description of the rescue.
Other aircraft and landing field
towers are contacted with a Lear 108-128 mc. transceiver mounted
on the instrument panel. Pilot Max keeps an "ear" on this (as well
as on the police call channel), leaving newscaster Donn free to
study developments on the complex highway panorama stretching below.
Chats with passing aircraft often help the Airwatch crew learn about
urgent traffic situations not immediately within their vision.
DX'ing Missouri. Just in case the main
equipment should fail, a battery-operated, crystal-controlled Motorola
transceiver is always kept ready to go. This set puts out about
3 watts at 26.19 mc. and can hold out for about 40 hours of normal
operation. The Motorola was the original set used by the Airwatch,
and by some freak of transmission is often picked up by Radio Station
KFRU in Columbia, Missouri. "We have a regular ritual here of listening
to the Los Angeles Freeway helicopter reports" wrote KFRU.
Once the G.E. equipment "konked out." On went "Mickey-Mouse"
(pilot Max's name for the Motorola transceiver), and just in time;
a serious freeway collision had occurred involving an immense truck-trailer
and four cars. Traffic started backing up for miles. Newscaster
minutes after I radioed alternate routes, the freeway was so clear
of traffic you could have fired a cannon ball down it and not hit
Cruising at about 80 mph one afternoon on a routine
freeway report "mission," the radio 'copter saw the first few wisps
of suspicious-looking smoke. Where there's that kind of smoke at
that hour in Los Angeles, there's probably a fire. There was; at
a codeine factory. Airwatch reported to the KABC base at 3:50 P.M.
The station called the Fire Department. The fire was snuffed out
Following the Cars. On weekends
the radio watchbird follows seashore-bound motorists to California's
jammed beaches. Motorists are given weather reports, visibility
estimates, water and air temperatures, and advice on parking problems.
At baseball games the 'copter is always welcome, since traffic is
How does the average driver feel about
Operation Airwatch? Well, when Max and Donn asked the drivers to
turn on their lights one evening, the bumper-to-bumper caravan responded
whole-heartedly. Result: the whole freeway system was lit up like
a fantastic Christmas tree. And that's a lot of watts.
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