Let’s Automate!
Dec 1, 2001 12:00 PM
For nearly 60 years, the Voice of America (VOA) has been the USA’s primary means of disseminating news and information throughout the world. Today, a network of 22 stations broadcasts material from 40 radio and three fully equipped television stations in Washington, DC, to more than 1,000 stations worldwide. One particular VOA relay station has some interesting stories to tell. Here is one of them.
The Bethany, OH, station was originally built during World War II. It was built so far inland because there was concern that German submarine activity along the East Coast might result in a coastal station being damaged or destroyed, and Bethany would be its backup. In fact, several of the rhombic antenna arrays at Bethany were aimed toward Europe.
Other antennas at Bethany were used to broadcast directly to Central and South America and to relay Radio Marti to these countries, as they are directly south of the Bethany location.
The Bethany station was also used for Armed Forces Radio and Television Service (AFRTS) until the service discontinued the use of the HF band.
Operating at frequencies between 6MHz and 21MHz, time of day and atmospheric conditions required regular frequency changes at Bethany. In addition to changing loading caps and coils, each frequency change required antenna switching. The antenna system required manual switching.
John Vodenik, a VOA transmitter technician now stationed in California, was an operator at the Bethany relay station. �To switch antennas, a technician had to go outside into the switch matrix, sometimes in extremely cold or stormy weather conditions, and throw at least two of the antenna switches, often more,� recalls Vodenik. �It took operating crews of three people as much as seven or eight minutes to change the frequencies. At one point, my crew had it down to a record of less than six minutes � but we had to hustle.
�In an attempt to get our speed up so we could continue to beat the other crews, we came up with the idea of automating the antenna switching.� So one day, Vodenik stopped at the local hardware store and bought an automation system. It consisted of a 200-ft. roll of ?-inch nylon cord.
The crew wanted to make sure that they built the automation systematically, so they decided that as a test they would only automate one switch the first time. So before it was time to switch to 6.030MHz, Vodenik and another crewmember went outside and pre-set all but one switch. They connected one end of the nylon line to the last switch handle, ran the line down the pole and through a pulley at the bottom so that it came off at about 90 degrees. The line then went into the building where an operator could sit back and relax until it was time to switch. All the operator had to do was tug the line, and the experiment would undoubtedly be a success.
As the scheduled time for the frequency change approached, the crew was anxious to see the automation system in action. After all, this could potentially put an end to the treks into the frigid cold and rain.
When the time came, the transmitter was taken off the air and the work began. The coils in the RF driver stage were changed, and the 15MHz shorting bar was removed from the output tank circuit. Everyone was looking forward to being able to complete the job without setting foot out of the transmitter room.
When it was time to switch, the crew gathered around the free end of the nylon line, and one crewmember picked it up. Recalls Vodenik, �He pulled on the line � and pulled some more. He pulled and pulled, and still the antenna didn’t switch.�
No one remembered that nylon stretches, and it surely did that day.
�After we had been off the air about eight minutes, the switch finally dropped. But there wasn’t enough force to cause it to close. So someone had to run outside after all and close the switch. We set another record that day � ten minutes for a frequency change.�
Vodenik says the group decided that the system wasn’t meant to be automated, and they never tried again. �We had to live down a lot of laughter, but we laughed too.�
Years later, Jim Hawkins, who maintains the Jim Hawkins’ Radio and Technology Page website visited the site. When he asked why the antenna switching wasn’t more automated, he was told, �Because it works fine the way it is.�
Photos by Jim Hawkins.
The Bethany VOA site had three Collins 821A1 transmitters. There were 22 different antennas held up by 110 telephone poles, some of which were later replaced with self-supporting towers. The rhombic antennas were 1,000 feet long per leg.
The Bethany station was dismantled in September 1995 as a result of budget cuts and a diminishing need for HF relays. Most programs are now relayed by satellite.
