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It was apparently informally known as “the woodpecker” because of the sound of the interference it would make. It’s interesting to read the amateur radio commun
by teeray 7y ago
It was apparently informally known as “the woodpecker” because of the sound of the interference it would make. It’s interesting to read the amateur radio community’s response to it at the time: https://www.qsl.net/n1irz/woodpeck.html https://www.qsl.net/n1irz/woodpeck.html
> “If you want to screw up a radar signal, all you have to do is send a return signal on its frequency which blocks out the echos. Hams, from the earliest woodpecker days, have been driving the monster off their bands by getting on the frequency and sending properly spaced dots back. The screen somewhere in Russia blanks out and the operators utter some Russian oaths and change the frequency to get rid of the interference."
- xxpor 7y agoThe opposite behavior is kind of scary. What prevents someone from faking a "missile echo" response?
- paulmd 7y agowikipedia says the transmitter used a pseudorandom sequence, so unless you could copy the PRNG output then you couldn't predict the sequence and generate appropriate returns. Amateurs would just jam the whole frequency so the radar couldn't hear any returns at all.
- Enginerrrd 7y agoSeems like it'd still be susceptible to playback attacks with a slight random delay.
- blattimwind 7y agoYes within d/c. So a priori you already need to be rather very close to the position of the object you want to fake appearing. At that point you might just as well put an object there.
- paulmd 7y agoI don't know what d/c means but if it's data connection then the fact that light (and other EM energy like radio waves) travel faster in air would probably be a problem for using that as a jamming approach
- blattimwind 7y agodistance divided by speed of light = time window for a successful replay attack
- paulmd 7y agoWhile I actually find this discussion interesting (serious), I just want to make the note that this is a military system and thought was undoubtedly applied to making it resistant to at least trivial jamming approaches. Hence the PRNG based timing for the transmission. It would be more compelling if you outlined some ways that that approach might be stymied and how the soviets might have counteracted that.
- oliveshell 7y agoWhat the Hams are doing is radar jamming/interference; it’s not the ability to make the radar screen show whatever you’d like. That would be much, much, much more difficult (if it’s even possible). As far as this sort of spoofing between nation-state actors, discussion is difficult because both the U.S. and Russia have been developing sophisticated ‘electronic countermeasures’ [1] for decades, and all their most interesting capabilities in this regard are certainly classified. [1]: https://en.wikipedia.org/wiki/Electronic_countermeasure https://en.wikipedia.org/wiki/Electronic_countermeasure
- jeherr 7y agoPut a reinforcement learning network on the task to recreate signals from a radar with a ham radio and see if it can learn it. That would be pretty sweet.
- dbcurtis 7y agoWell, that is kind of stale news. The sending of a few dots worked for a few weeks. I even participated. But a pack of angry hams sending dots was worse than the woodpecker. But anyway, after moving off the ham bands for a while, the woodpecker came back with a chirped signal. That was essentially unjammable. Over-the-horizon HF radar needs to closely follow the MUF, staying just under it. So the woodpecker would drift up and down through the ham bands as the day want on.
- femto 7y agoI was working on the Jindalee OTHR at the time. We used to sit in the control room listening in on the Woodpecker. We also had quite a bit more power then the HAMs (beamformed) so they didn't ignore us. (Jindalee also stayed clear of the HAM bands. The radar had frequency exclusion tables built into it and there was a switch which allowed the tables to be overridden if necessary. A number of techs were HAMs and made sure the HAM bands were respected.)
- 8bitsrule 7y agoEastern Oregon had one of those, used from 1985-97, paired with one in California. (What frequencies?) After the cold war, WP says, it was used by the Border Patrol.(??) https://en.wikipedia.org/wiki/Christmas_Valley_Air_Force_Station https://en.wikipedia.org/wiki/Christmas_Valley_Air_Force_Sta...