Someone is jamming BBC broadcasts in the Middle East
bbc.co.uk
bbc.co.uk
Given that these satellites are geostationary they can be seen from a very wide area on the ground. Back in 2003 Telstar-12 was jammed from a station in Cuba apparently run by Iran (http://www.atimes.com/atimes/Middle_East/EH22Ak03.html) to block transmissions to the Americas and Europe.
Thinking about it, jamming the downlink in a large area to get the same effect seems to be much harder than jamming the uplink.
But it might be worth noting that you can use spread-spectrum techniques (http://en.wikipedia.org/wiki/Spread_spectrum) to overcome jamming. Spread spectrum has some similarities to an encryption scheme, because the method used to smear the signal around uses a pseudorandom sequence which is known to the encoder and the decoder.
CDMA (http://en.wikipedia.org/wiki/Code_division_multiple_access) cell phones use this idea.
As you note, this type of encryption takes place at the RF level.
You increase your timing accuracy by 10x, and the jammer's power requirements increase by 10x (crudely speaking -- not a 1:1 trade, but directly linked).
We're talking about direct sequence, which increases the bandwidth of the signal but keeps the same carrier. To jam that (theoretically) you need large power through the entire band.
Both frequency-hopping and direct-sequence spread energy over a larger bandwidth. Direct-sequence does not explicitly frequency-hop, but the time-domain switching it uses will spread the energy out in Fourier space.
http://en.wikipedia.org/wiki/Direct-sequence_spread_spectrum
DS Spread Spectrum spreads the signal over a larger frequency range- because power is conserved it can even hide behind ambient noise.
When un-spread, the noise is spread out and the signal is "collapsed" back to the original bandwidth.
The most basic of jamming is to drown out all other communications with high-power noise. But in the case of illegal/covert activities this isn't ideal as your transmitter will be pretty easy to find.
So then you have to pretend to look like a legitimate signal. Which is where encryption and modulation can help. But then application level encryption isn't going to help against basic jamming.
Jamming the uplink is much easier. All you have to do is over-power the signal from the transmission station(s) up to the satellite. Encryption doesn't do you any good. Having redundant uplinks also doesn't do much good since the resources of the satellite are limited, and the amount of power you can get here on the ground is more or less unlimited by comparison. There are multiple uplink transponders (chunks of spectrum used as carrier frequencies), and you can allocate them in a redundant fashion, but it's expensive due to the limited resources on the sat.
The interesting, and undisclosed, question is whether or not the attack is only affecting the BBC? If so, then it's a more sophisticated attack targeting just the carrier frequencies (uplink transponders) being used by the BBC. A high power wide-band attack is crude but easier to perform, and would jam all of the channels broadcast from the satellite since it would over-load all of the uplink transponders.
Sadly, there are still a lot of old and poorly designed satellites still in use; it's kinda like finding unfixable Win95 systems on your network infected with malware. Since they're in orbit and cost a whole lot of money, fixing or replacing them aren't a viable options.
The only good news for older satellites is both the uplink (to satellite) and the downlink (to ground receivers) often have somewhat adjustable footprints. If you can identify the ground location of the jamming signal, you might be able to exclude its region from the uplink footprint. The trouble is, if the satellite is also being used for things like sat-phones, then you just cut off all customers in the excluded area of the uplink footprint.
By the fact that this was made public, there's probably nothing that can be technically done about the jamming.
I started messing around with satellite based data broadcast systems in high school during the mid 80's due to my dad's work. The systems delivered real time stock, commodities, and futures data at a time long before the craze of web based "Internet Trading". Back then, only the most serious trading businesses had real time quotes and the systems were connected by either satellite or dedicated lines. Since it was a "broadcast" systems (one-to-many), it's fundamentally similar to satellite television broadcasting.
The two-way satellite data/voice systems work on similar principles but there are a few major designs in use. Some satellite phones work with an array of sats in Low Earth Orbit (LEO) and only require an adequate pole/stick antenna. Other satellite phones work with satellites in geostationary orbit and require a two-way dish for both broadcast and receive. All of the satellite based Internet Service Providers (ISP) serving rural areas use geostationary satellites.
Some people wonder how Steve Wozniak can live in (near) the Silicon Valley and still complain about broadband speeds/coverage in the US. He doesn't live too far from me up in the hills above the valley, and the odds of fast broadband every reaching up here are very slim. As you might expect, I've run a satellite based Internet connection in the past, so I got a chance to learn the internals of those systems as well.
Satellite based Internet connections have very high latency. The minimum ping time is roughly about 480 ms ... umm, I think, but for fun, let's do the math:
Geostationary Orbit: 35,786,000 meters elevation.
Speed of light: 299,792,458 metres per second.
The ping request would travel from you up to the satellite and then back down to the ground station, so it travels twice the distance of geostationary orbit (up and back).
The ping reply would also travel from the ground station up to the satellite and then back down to you, so it also travels twice the distance of geostationary orbit.
(4 * 35,786,000) / 299,792,458 = 0.47747
Yep, pretty close to the 480 ms I remembered, but that's just the raw travel time under totally unrealistic conditions. In reality, you're a lot farther away from the satellite rather than directly below it at sea level, and there would also be some over-head for the computer systems involved.
The above also assumes you're on a dedicated transponder (i.e. you have a very expensive chunk of frequency dedicated to your sole use), but since you never get a dedicated transponder on a consumer service, ping times can be in excess of 3000 ms on a regular basis. The transponder space allocated to the ISP is shared amongst all of the ISP's customers via TDMA. FDMA, FTDMA, and I think occasionally CDMA. Even when you know how to tune your own TCP/IP stack and all of your applications to adjust for the high latency, using a lot of typical things (like web browsing) are still absolutely miserable. Think about it this way; every time you click on something, you have to wait 3 seconds for anything to happen. It drives most people nuts, so using a satellite based ISP is a last resort, and in some ways it sucks more than using a 14,400 baud phone line modem.
You see, once you learn some of the basics, then you have a base for learning more fun stuff, but most importantly, you also gain the advantage of being able to "reason" about how other related things work.
And, reading between the lines, that right there is possibly your biggest clue. Beyond the juvenile intrigue of someone breaking something just to see if they can, or even some chintzy politically motivated anti-propaganda operation, another motive might lie in assisting/disrupting (depending on whose side your on) clandestine operations in a specific geographic area.
It's tempting to wonder if maybe it's just some Greek crypto-anarchists horsing around, but more likely it'd be someone with heavy-weight resources and know-how like CIA/GRU agents operating in Syria.
From the article: "...together with a number of other broadcasters, is experiencing deliberate, intermittent interference to its transmissions to audiences in Europe and the Middle East."
If the jamming is coming from Syria, I'd say it's the government trying to jam the encrypted satellite radios of the rebels. (Some of the aid to the rebels from the US and Europe was for secure comms.)
http://www.google.com/hostednews/afp/article/ALeqM5hXpzxDWlS...
Apparently Syria sought Iranian assistance to disrupt the signals.
http://www.telegraph.co.uk/news/worldnews/middleeast/syria/9...
Its also a popular sub-activity of HAM radio, in which its called "Foxhunting."
This is broadly how the SETI program works for example.
The device is transmitting at high power, it's like beacon, and very easy to see.
If you do it in war the jamming station is likely to be visited by a http://en.wikipedia.org/wiki/Anti-radiation_missile such as the http://en.wikipedia.org/wiki/HARM_missile
And to levy a huge fine. Do not do this.
Calling channels are defined by the ARRL, not the FCC.
Oh, and HAM is not an acronym, it's just ham.
Kind of like trying to see a flashlight when someone's shining headlights at you.
But ... if you're shining a really bright light then everyone who cares to look can see where it's coming from.
Obviously whoever is "jamming" them is not going to read this, say, "My bad" and just stop.
I am really wondering who their real audience, in this case, is. Is this an attempt to influence government actions in the U.K. or the EU itself? Is this part of a public opinion swaying operation to sway the British people so that more of them will support the idea of military action in Syria?
It's all speculation at this point, but I do wonder.
If nothing else, it will help some of the affected viewers know to quit smacking their televisions on the side.
The identity of the culprit should be obvious!