
Duga radar: Enormous abandoned antenna hidden in forests near Chernobyl - olvy0
https://edition.cnn.com/travel/article/duga-radar-chernobyl-ukraine/index.html
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hilbert42
I well recall the Duga radar, although back then we only ever called it the
woodpecker because of the chirpy noise it made.

Its very powerful signal used to flood large chunks of the HF/shortwave radio
spectrum (3-30 MHz) and render sections of it unusable for legitimate users
(i.e.: radio stations operating within the ITU (International
Telecommunications Union) radio regulations and technical standards).

Back then, it seems the Russians—or I should say the USSR—didn't give a damn
about standards when it came to Cold War activities.

Duga used to check for a quiet part of the radio spectrum and then start its
chirping activities (being radar, and even though its transmitters were
extremely powerful, it still needed very quiet channels in order to detect its
own very weak reflections/echoes if it was to work properly). Thus, it would
land anywhere where it was likely to sufferer minimum interference from other
radio stations (even though these other stations were very much weaker in
power than Duga was, they could still easily drown it out).

I recall amateur radio operators—who use even much lower power than these
other broadcasters do—were able to chase it out of their own bands with only
few tens of watts—so important was it for Duga to have a very clear channel.
Amateurs used to deliberately land on Duma's frequency and transmit there,
this would interfere with its reflection and thus screw up its radar
activities. When interfered with Duma would then move across the band to the
next quiet spot and start over again. The crafty cunning amateurs would
effectively chase it on and on across their bands until they had gotten rid of
it.

Nevertheless, Duma was a remarkable system and there's been videos of its huge
antenna arrays and transmitter buildings on YouTube for a few years now.
Moreover, there's a few showing intrepid climbers clambering all over these
very high antenna arrays. Intrepid in more than one sense, as Duma is in the
Chernobyl exclusion (radiation) zone only a few kilometres away from the
crippled reactor (presumably, they're not too concerned with the radiation
levels from the reactor).

For any techie who is even vaguely interested in RF engineering or ionospheric
propagation, Duma is a truly interesting relic/artifact of the Cold War as
well as an amazing technological curiosity.

