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Receiving unintentional voice transmissions from GPS satellites

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71–80 of 93 posts

Re: Receiving unintentional voice transmissions from GPS satellites

#71
post #3

Quick summary: > Many navigational and meteorological satellites carry a search and rescue (SAR) repeater which is intended to receive UHF emergency locator beacons and rebroadcast them in the L-band or higher. However the repeaters appear to be picking up all sorts of other signals from the ground, including voice transmissions.

Makes me wonder if these ever were used out-of-spec for transmission deliberately by parties. (Thinking spy stuff but it could also be just hijinx.)

[deleted]

Re: Receiving unintentional voice transmissions from GPS satellites

#72
post #3

Quick summary: > Many navigational and meteorological satellites carry a search and rescue (SAR) repeater which is intended to receive UHF emergency locator beacons and rebroadcast them in the L-band or higher. However the repeaters appear to be picking up all sorts of other signals from the ground, including voice transmissions.

Makes me wonder if these ever were used out-of-spec for transmission deliberately by parties. (Thinking spy stuff but it could also be just hijinx.)

The article suggests pirates which makes some sense.

Re: Receiving unintentional voice transmissions from GPS satellites

#73
post #8

Few things evoke feelings of the early internet like intercepting unencrypted communications in the wild with off the shelf hardware and software. It's some how comforting to realize this is still possible today.

If you keep emitting radio wave of these frequency for general communication purpose, the local authority will eventually catch you.

If the local authority or civilization corrupted, good luck rebuilding it.

Re: Receiving unintentional voice transmissions from GPS satellites

#74
post #36

Earlier quoted context omitted.

You still need to exchange keys. You can't get around that. Otherwise, how do I know the public key you sent me over the radio is YOUR public key and not someone else with a more powerful radio?

By having the key signed by someone who you trust. Which in a military typically means the central command.

You still need to physically meet someone you trust to exchange keys, however you slice it.

Re: Receiving unintentional voice transmissions from GPS satellites

#75

Earlier quoted context omitted.

Considering how much progress that has been made in encrypting internet traffic radio seems painfully slow in evolving to be more secure. Edit: specifically radio protocols not carrying internet traffic

Aren't there FCC regulations that forbid encryption over non-military radio?

I wouldn't have thought so, since most DMR products are certified for use in the US by the FCC and include fairly strong encryption.

Also, do bear in mind that most people don't need to care what the FCC says, or stick to their rules. I'm currently operating equipment that quite thoroughly violates FCC rules, and there's not a thing anyone can do about it :-D

Re: Receiving unintentional voice transmissions from GPS satellites

#76

My father is a radio lover, a DXer, and sometimes nearly contemplated a ham license. So I grew up with him listening to shortwave and other bands, he explained all the concepts, WWV would be on for two hours at a time (you could literally count every minute). Another fixture was the police/fire scanner that would be on most evenings, especially when we heard sirens. Dad put up a nice rotary Yagi VHF/UHF tower for the…

I guess you're in the UK? The UK has this really weird law where it's legal to listen to anything but you may not repeat what you heard. I don't know of any other country that has that stipulation. In most of Europe you can listen all you want and talk about it. I think in the US some frequencies were forbidden to listen to and to this day these are blocked on scanners. Not sure why as analog cellphones are long obso…

Even listening is in a grey area in the UK; it’s a separate offence to “use wireless telegraphy apparatus with intent to obtain information as to the contents, sender or addressee of any message” where you aren’t an intended recipient. But the intent bit is probably hard to prove in practice.

Re: Receiving unintentional voice transmissions from GPS satellites

#77

My father is a radio lover, a DXer, and sometimes nearly contemplated a ham license. So I grew up with him listening to shortwave and other bands, he explained all the concepts, WWV would be on for two hours at a time (you could literally count every minute). Another fixture was the police/fire scanner that would be on most evenings, especially when we heard sirens. Dad put up a nice rotary Yagi VHF/UHF tower for the…

I guess you're in the UK? The UK has this really weird law where it's legal to listen to anything but you may not repeat what you heard. I don't know of any other country that has that stipulation. In most of Europe you can listen all you want and talk about it. I think in the US some frequencies were forbidden to listen to and to this day these are blocked on scanners. Not sure why as analog cellphones are long obso…

I'm not sure we do have that law in the UK? The relevant legislation seems like it would be https://www.legislation.gov.uk/ukpga/2006/36/section/48; but that makes it illegal to either intercept or disclose.

Re: Receiving unintentional voice transmissions from GPS satellites

#78
post #3

Quick summary: > Many navigational and meteorological satellites carry a search and rescue (SAR) repeater which is intended to receive UHF emergency locator beacons and rebroadcast them in the L-band or higher. However the repeaters appear to be picking up all sorts of other signals from the ground, including voice transmissions.

Makes me wonder if these ever were used out-of-spec for transmission deliberately by parties. (Thinking spy stuff but it could also be just hijinx.)

Unless someone has proof otherwise, I'd bet that they've never been used for that purpose. Every major government is listening to this SARSAT downlink so it's probably better to use something less visible.

Re: Receiving unintentional voice transmissions from GPS satellites

#79
post #23

Earlier quoted context omitted.

For amateur radio, but no in general.

And it's not even actually illegal for amateur radio though there continues to be debate on the topic due to the phrasing. I do think that encryption is firmly outside of the amateur culture in most cases, but legality is well covered here: https://www.n5dux.com/ham/files/pdf/Data%20Encryption%20is%2...

In the UK, it's illegal to encrypt for the purposes of obscuring communication. There was a lot of noise about G3RUH modems in the olden days when 9600bps packet was starting out, because they used a "scrambler" to whiten the spectrum of the data being sent, and people assumed that meant it was using a secret key to encrypt traffic.

I mean, in a sense it was - you're trying to make thing with long runs of patterns look as much like noise as possible, which is the goal of encryption - but in order for it to work as a modem both ends have to have the same "key" which was a very short LFSR that would pull into sync during the training burst.

In practice, at least in the UK, you can more-or-less do what you like as long as you're not making a nuisance of yourself. You literally cannot pay Ofcom to investigate anything on the amateur bands, although you might get a lot of grumbling from daft old bastards.

Re: Receiving unintentional voice transmissions from GPS satellites

#80
post #20

What did the conversation overheatd in that video say?

Apparently it is related to some "taxes services" in China. At least that's what the author of the video says.

"Taxi service" would be more likely.
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