A bit of ham radio history:
For hams who were active back in the 1970’s through the 1980’s on any HF band, an often annoying interference was heard day and night. This interference was commonly known as the Woodpecker because it cycled on and off in 16hz increments and sounded..well…like ole’ woody woodpecker….tap tap tap tap tap. I was so loud that it could easily drown out WWV’s time signal. What was woody ? It was a long range, over the horizon radar system near Chernobyl, and was designed to bounce radar signals off the ionosphere and deep into the USA to detect potential nuclear missile launches aimed toward the Soviet Union using back scatter off of the ionosphere. For USA hams, it was simply annoying QRM. Eventually, various gadgets were created to tackle the Woodpecker.
AEA made a device called the “Moscow Muffler” which would sync with the woodpecker and notch it out of your receiver. It worked, somewhat, but not entirely. Eventually, hams learned to simply switch over to CW and send a string of dits for 20 seconds or so. Apparently, this would confuse the radar (getting a false echo bounce) and the radar sweep would move to another part of the radio spectrum.
At 5 megawatts (5 million watts) of power, it’s no wonder the $89 “Moscow Muffler” didn’t exactly work as hoped…. The huge transmitter used nearly 25% of the entire power output of the Chernobyl nuclear power plant.
The DUGA- 3 OTH (over the horizon) radar was decommissioned in 1989, as the cold war came to an end and a new era of Peristroyka ushered in historic changes to, and then the collapes of, the Soviet Union.
The 1980’s were a fun time in ham radio. QSL cards from the cold-war soviet union were sometimes difficult to get and always prized. They were often printed on very thin paper (recycled) and were quite colorful and creative despite the obvious scarcity of resources. All cards were strictly monitored, and to QSL, one had to send a “green stamp” (dollar bill) or an IRC (international reply coupon) to PO Box 88, Moscow, Russia, USSR. Those indeed w
Here is a youtube video of a lady who is visiting the infamous DUGA-3 radar antenna site. She does a remarkable job in the video to show the massive size of this antenna.
And the original woodpecker in action as heard over WWV:
Finally, a bit more about DUGA-3