Yes, but we're not talking about Starlink. I'm talking about Othernet, which I mentioned above.

It is receive only-- not an uplink.

(I'm sure a tiny bit of RF leaks out of the LNB, but that could be mitigated as it is not designed for stealth).

> I'm sure a tiny bit of RF leaks out of the LNB

Any receiver using the heterodyne principle (this includes most current digital radio modems) is trivially detected by its local oscillator, often to some considerable range (potentially hundreds of metres).

In the UK, the BBC used to exploit this, with radio detection vans patrolling the streets for unauthorized receivers, to fine people for watching TV without a license. So did the USSR with shortwave receivers, where the penalty was potentially more than a fine. A satellite receiver is the same, in principle.

> Any receiver using the heterodyne principle (this includes most current digital radio modems) is trivially detected by its local oscillator, often to some considerable range (potentially hundreds of metres).

I'm sorry. This is not intrinsic; this is a design choice. Yes, most LOs just care about getting under legal emission masks, but there's nothing to prevent one from bringing it much lower.

Further, as I explained: the LO frequency of the LNB for the first conversion is often the exact same frequency as you'd use to downconvert digital TV broadcats.

It's not intrinsic, no. It's possible to design a receiver with its local oscillator emissions to be down to an arbitrarily low emission standard. (But who actually does that?) And not all reception techniques require a local oscillator at all. Still. My point was merely that with an average radio, which was designed to just not be harmfully interfering, such as typical satellite TV receiver? It's quite possibly lit up like a beacon if you know what to look for.

> with its local oscillator emissions to be down to an arbitrarily low emission standard. (But who actually does that?)

Better testing to compliance standards has pushed LOs down way lower than they were in the 40s-60s. We have relatively cheap high quality spectrum analyzers and big integrated measurements. So-- kinda everyone pushes things down pretty low now.

> My point was merely that with an average radio, which was designed to just not be harmfully interfering, such as typical satellite TV receiver?

Yah-- this LNB looks just like a satellite TV receiver, with the exact same LO frequency. So your rogue downlink looks exactly like something that there's hundreds of innocent versions around.

Then a SDR inside your house chooses a different signal from the transponder and gets the data.

In countries this would be a problem in right now, satellite TV is often banned too.

Satellite TV is exceptionally common in Pakistan, I believe.

And Iran. Still banned though.

[https://gulfnews.com/world/asia/pakistan/government-bans-imp...]

Of course, so are most drugs in the US.

I believe that receiving state media with state-approved satellite services is A-OK. This is an import ban on unapproved equipment.

It’s also legal to take state approved drugs in the US.

Point taken though!

The point is, there's a whole lot of (mostly legal) satellite receivers around, so looking for satellite receivers doesn't seem like a great way to spot dissidents immediately.

Satellite TV receivers are generally frowned upon in authoritarian societies, I believe.

It's trivial to force all the registered satellite broadcasters servicing a country off-air, if your already willing to arrest the former prime minister in public view, so anyone left with a hot dish would be easily identifiable.

So, you turn off all the state TV coming by satellite... so that you hope that all the satellite receivers get unplugged from the wall (else, they're likely to be listening to reacquire and get program guide etc)... so that you can drive around in vans and look for the -remaining- satellite receivers as a conduit of information coming in.

I mean, I guess it's possible. But probably not your top priority during a time of potential unrest. And it probably won't work that well as a way to find people with the links.

Any non zero amount of incoming radio signal to a hot dish would be suspicious, and easily identifiable, if all the registered broadcasters are offline.

I suppose the heterodyne frequently (the 465 kHz of AM, for instance) can be effectively hidden. Put your whole receiver into a metal enclosure, have a high-pass filter before the antenna connector, and a low-pass filter before the outputs and power connectors.

Such a device would likely look peculiar enough to be easily recognizable, though, so you'll need to hide it, possibly inside some innocuous-looking other device or enclosure.

The whole setup becomes somehow more involved, but still cheap enough.

> I suppose the heterodyne frequently (the 465 kHz of AM, for instance) can be effectively hidden. Put your whole receiver into a metal enclosure, have a high-pass filter before the antenna connector, and a low-pass filter before the outputs and power connectors.

Yes-- and every piece you mention is "quality radio design 101".

> Such a device would likely look peculiar enough to be easily recognizable

I'm not sure about that.

The biggest most suspicious thing is, if they're resourced to investigate everyone with a piece of coax going outside-- where does yours plug into?

Of course, if you're really dedicated-- get a satellite TV receiver, empty out the nice metal box, put the receiver inside ;).

Sounds useless for the internet (where every protocol is fundamentally two way), but great for ‘Radio America’ type broadcasts. Of course, so is shortwave.

definitely not solving the same ‘problem’ at all though.

You're replying to a thread where I started by saying "Maybe the internet as a whole is intractable."

could you say this seven more times?

I'm worried I'll have to :/