To jam the downlink, you'd need to be between the satellite and the
ground receiving dish, or have line-of-sight to the receiving dish and a
ton of power. This only disrupts the one receiving dish, so the attack
is isolated.
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.
> ...if the satellite is also being used for things like sat-phones...
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."
I think you hit the nail on the head. This is very interesting in light of Turkey intercepting "radar" equipment from Russia to Syria.
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.)
The best way to learn is relentless curiosity. There's always a big
difference between the stuff you need to know and the stuff you want to
know. If you're truly fascinated by how things work and you really want
to know how they work, learning is much easier and far more enjoyable.
The best part is, even if the learning is actually horribly difficult,
you never notice you're suffering since you're having a lot of fun.
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.
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.