Can a “satellite hunter” be hunted?
It’s really not an old thread. It’s still a very current discussion. It does not take a real high budget to start hunting. Let me elaborate a little about what I’m doing with crude experimenter equipment for under $100.
What does an LNB do? How do they work?
Outernet DreamCatcher 3.0 will use a Standard Ku LNB
In a nutshell, it receives signals between 11.70 and 12.20 GHz and converts the entire block down to 950–1,450 MHz by subtracting 10.750 MHz.
Since a Outernet is just a receiver…
You would think that it has no need to be secure because it’s only one way. I thought this very argument and found that it’s really not true. The Local Oscillator at 10.750 GHz does radiate. In the thread above, I used a Universal LNB to find the leaking carrier from the Outernet LNB.
Can I detect an LNB with another LNB?
The Universal LNB can receive the 10.750 GHz carrier in the Ku-low band (10.70–11.70 GHz). It does this by subtracting 9.75 GHz with its’ own LO, resulting in a down converted block 950–1,950 MHz. I can tune that block with an RTL-SDR, a low-cost Software Defined Radio. The answer is a resounding yes.
So what’s with the picture above?
The picture in my last post above is the 10.750 GHz carrier emitted from a Standard LNB. The horizontal axis is frequency, and the vertical axis is signal strength. Sine that indoor experiment, I have since found that I can detect that carrier with simple equipment at distances of 30 meters or more with plenty of signal to go. The weather has been bad, so I have not taken the experiment any further.
So why is this a worry?
The eventual target market for Outernet is for countries where there is no Internet. Some of the governments don’t like the freedom of information, so in turn they don’t like free speech, the freedom of the press, and the Internet. In some places, the government collects receiver taxes so they can regulate who listens and what they listen to.
Since I’m familiar with EMC/EMI testing, and knowing that LNB could be detected, I’ve taken an interest in knowing to what extent (if any) there is a problem.
How much of a signal are we talking about?
It’s not how much, but how small of a signal I was able to detect. A candle emits roughly one watt of light (around 30dBm). The signal I’m receiving with my pedantic hardware is in the neighborhood of -40 to -50 dBm. That’s like 1/10000000 to 1/100000000 of the light from a candle! It’s an incredibly small signal. But I’m using essentially another copy of the device to listen to a satellite 42,000 km away to detect it.
I’m in a sense telling you that I might be able to detect a computer, cellphone, shortwave, etc that’s turned on and not connected to any network the Internet in the middle of a desert with incredibly cheap hardware. LNB’s are incredibly sensitive devices. For $15, RTL-SDRs are amazing devices as well.
If only I had a $75K spectrum analyzer…
I might be exaggerating a little, but with enough resources, you probably can find a cellphone charger from an airplane. Buck chargers do radiate too, you just need to know where to look.
I actually think that wild animal poachers could be detected with amazingly simple gear.
–Konrad, WA4OSH
