During the Gulf War, I had loaned Van Harden a short wave communications receiver so he could listen to international broadcasts. He asked what he could do for me and I requested a tour of the legendary WHO transmitter site near Mitchellville. He told me that the engineers always did routine maintenance on Thursdays and that he would take me out there during that time. This would have been in the summer of 1991.
At that time, the primary transmitter was a 50,000 watt Harris MW50C3 (Pulse Duration Modulation), installed in 1979. On Thursdays, they always pulled the Harris down and fired up the 1950 Westinghouse. What a treat! I got to see the old girl in operation, complete with the glow of her huge vacuum tubes. Tubes so large that to change them, a small crane was used to pull and lift them. The serial number on that proud transmitter was "3." Usually, they would make the switch from the Harris to the Westinghouse around 8:30AM and switch them back sometime in the early afternoon.
Presently (2002), there is a newer Harris DX-50 totally solid state, (much smaller) main transmitter and the 1979 Harris is now the backup.
The new Harris DX-50 uses over a thousand high powered transistors that by using digital control are rapidly turned on and off at exactly the right rate to fully modulate the 50,000 watt signal. In my own terms, "This would be like coordinating millions of ants to lift a large security safe and make it dance around the room."
The 1950 Westinghouse is still there, and we have been told, could easily be put back on line.
Up until the mid 1970's, WHO-TV transmitted from the Mitchellville site. Although the old RCA TV transmitter is now totally gone, it was still in place on that day that I visited. That transmitter was huge. One could literally walk around inside it. I have included a couple pictures of the TV transmitter.
Something I remember that impressed me about the building was the fact that there is copper screen inside the exterior walls, which provided electrical shielding inside the building from the strong electromagnetic fields generated by the antenna. The building also had living quarters for a resident engineer and family.
Interior pictures of WHO transmitter site -- 1991
Specs for Westinghouse 50 HG-2 installed in 1950
Exterior pictures of site taken in 2002
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