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Old 16-07-2014, 12:16   #136
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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Then it's called rtlsdr_pi_0.10-1_[arch].pkgtype. (Are you the author boat_alexandra? I really got curious about that plugin but haven't tried it yet.)
Yes, I am the author. The plugin is very small, all it does is calibrate and control gr-ais or rtl_fm and aisdecoder and pipe the ais stream into opencpn. Could manually run these programs and get the ais without the use of the plugin.
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Old 16-07-2014, 13:29   #137
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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Yes, I am the author. The plugin is very small, all it does is calibrate and control gr-ais or rtl_fm and aisdecoder and pipe the ais stream into opencpn. Could manually run these programs and get the ais without the use of the plugin.
Well thank you! It saved me a lot of thinking!
I wondered if it perhaps contained the ais_rx.py. I personally found it much easier to connect that to ocpn than my 10 year old serial GPS...

Best regards
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Old 16-07-2014, 13:34   #138
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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Yes, the "land of the free" is a joke.

Mine picks up anything from 12mhz to 1.2ghz. I know another which goes to 2.2ghz. So, yes you can pick up cell phone transmissions. I looked up the section you quoted, and it is stated by fcc.gov that it's obsolete and without effect.
I finally found the "editorial revision" made by the FCC when they obsoleted the US 47 CFR part 15.37f regulation. Unfortunately, it looks like they simpy pointed to another regulation as replacing it (US 47 CFR part 15.121)

15.121 looks like it could still be a problem. Again, I'm no lawyer, and it probably would take one to wade through all the editorial revisions. It's hard on the eyes, and the stuff is buried in a labyrinth on the FCC site, so it's a bit hard to say for sure.

You might want to take a look.
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Old 16-07-2014, 13:54   #139
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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Yes, the "land of the free" is a joke.

Mine picks up anything from 12mhz to 1.2ghz. I know another which goes to 2.2ghz. So, yes you can pick up cell phone transmissions. I looked up the section you quoted, and it is stated by fcc.gov that it's obsolete and without effect.

In most parts of the world its illegal to listen to any radio signal without licensees permission. In fact with VHF I must keep " secret " any information I hear that doesn't pertain to me !!!!

Dave
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Old 16-07-2014, 14:06   #140
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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In most parts of the world its illegal to listen to any radio signal without licensees permission. In fact with VHF I must keep " secret " any information I hear that doesn't pertain to me !!!!

Dave
Yes - it's not just the US that regulates the crap out of things. Still - I'm feeling a little anal retentive, given the (probably low) likelihood that anybody would ever be on the wallet shrinking end of any action. Guess I'm spoiling everybody's fun.

I'm predisposed (genetic thing) to playing it too straight. So, for the time being, I'll have to do without one of these fancy gizmos. I'll have to be content to read about all the fun you all are having. Bummer.
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Old 16-07-2014, 14:33   #141
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Sean is the author and you will find the main development thread for his plugins posted here.
http://www.cruisersforum.com/forums/...ml#post1443580
This thread is used to inform when there are updates etc.
Comments, testing, results etc about particular plugins should be entered into the appropriate thread for the specific plugin to keep things organized.
I suggest you read down to the most recent entries to get a sense of the developments.

The Beta testing and comments Thread for RTLSDR_pi is here:
http://www.cruisersforum.com/forums/...-102929-4.html

We would very much like to have some users test this with dongles!!!
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Old 17-07-2014, 06:23   #142
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

A closer look at US 47 part 15.121 makes me think (uneducated opinion) that the regulation is really a much more restrictive version of 15.37f. It disallows any scanner or frequency converting device (marketed as scanner or with scanner) that may be easily modified by users to gain access to the cellular bands. By FCC definition, I'm guessing the dongles are frequency converters. Whether or not they'd be considered to be scanners is a question I don't know the answer to. I'm not the expert, so don't take my word for it! Since the dongles are not expressly marketed with the word "scanner", are they OK? Again, I don't know. They probably aren't marketed specifically to be used with scanners, necessarily. But they could be, with SDR. It's very hazy, so I don't know how to interpret the situation. The regulation uses the word "design" - which further muddies the water. The FCC pages for editorial revisions are what you're likely to land upon if you research this subject, so here's the latest (more concise) finalized reg for 15.121 (as of 2014):

eCFR — Code of Federal Regulations

I tried to find information for a dongle with the 824-900 Mhz range blocked, but so far have not found anything. I did see plenty of internet pages in Google listings for "cracking cellular channels" and a few of those articles used the kind of dongle we're talking about. I'm guessing the target market for these things is outside of the US. I don't see any information that indicates any of the TV dongles have blocked ranges, but maybe some of them do (block). A dongle that blocks the range (824-900Mhz) - would be good to go.

If anyone finds a dongle that has the 824-900 Mhz range blocked, let me know! I'm interested!

Disclaimer: I'm not a lawyer, so disregard this entire message.
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Old 17-07-2014, 07:04   #143
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

The TV sticks you buy are sold with software that does not allow tuning of cell signals. The aftermarket software is what allows all range tuning.

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Old 17-07-2014, 07:12   #144
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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The TV sticks you buy are sold with software that does not allow tuning of cell signals. The aftermarket software is what allows all range tuning.

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If that's true, then maybe we're in the clear. The regs make use of the term "scanner" pretty liberally, and a frequency converter is not necessarily a scanner. If the frequency converter is not intended to be used as/with a scanner, is it OK? I don't know. The question would be whether or not the software is easily modifiable to allow cellular range reception. Is the software tied (with keys, etc) back into the dongle to prevent the derailing of the blocking action? It seems the dongle still would have to be involved in order to make it difficult to avert the mechanism. Then it becomes a matter of defining "easy".

This makes me sound pretty anal/banal/ridiculous - but we'll all feel more comfortable about this whole range of technology if we get the facts nailed down.
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Old 17-07-2014, 07:42   #145
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

The regs are very scary to me. The scanning thing is not being refered to in the rules as an automatic or built in function so an old radio with a dial you can spin back and forth across the band with your finger would fit the regs definition of a "scanning" device.

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Old 17-07-2014, 07:50   #146
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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The regs are very scary to me. The scanning thing is not being refered to in the rules as an automatic or built in function so an old radio with a dial you can spin back and forth across the band with your finger would fit the regs definition of a "scanning" device.

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You're probably right about that!

Then, there's the newer cellular frequencies on 700 Mhz and 1.8 GHz. I don't know if they are specifically referenced by 15.121 or not. In some places, the regs talk about "cellular frequencies" in general, and in other places, specific frequencies. Part 15.121 points to part 15.22, which has the 900 Mhz frequencies listed. I'm not sure how 700 Mhz and 1.8 Ghz fit into the picture. Some of the dongles don't go up to 1.8 Ghz anyway. In other countries, there are still more frequencies. Like you say, it's scary. Yet, if we could get it all nailed down, we could make some excellent use of these new toys.
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Old 17-07-2014, 08:52   #147
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

I don't think any of these things are marketed to the US (compatibility issue), and instead the devices are targeted to the European/Asian TV markets and associated standards/specifications. I don't have a clue as to legal aspects of receiving signals in other countries outside the US.

The US situation seems crazy in a way. It's like the idea of walking around in public places, where it's been made illegal to hear certain types of people. So, when you see one of the off-limits people, you have to put your special earmuffs on.
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Old 17-07-2014, 09:12   #148
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

The cellular signals are encrypted anyway, so it's not like you can hear their conversations. You would be able to determine perhaps how much cellular traffic there is. Furthermore these devices are receivers not transmitters so they cannot interfere with any signal. Finally, if they are illegal, why can you buy them so easily? High powered lasers for example they refuse to ship to certain countries.

Obviously they have enough litigation to leave anyone confused, and also to allow any court to interpret the situation any way they want to.

Anyone can build a radio from basic components which picks up signals from any frequency, or by replacing the crystal in an existing radio. If there is a law that forbids this, then it is conflicting with basic freedoms and it's probably not worthwhile to live in that country.
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Old 17-07-2014, 11:17   #149
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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The cellular signals are encrypted anyway, so it's not like you can hear their conversations. You would be able to determine perhaps how much cellular traffic there is. Furthermore these devices are receivers not transmitters so they cannot interfere with any signal. Finally, if they are illegal, why can you buy them so easily? High powered lasers for example they refuse to ship to certain countries.

Obviously they have enough litigation to leave anyone confused, and also to allow any court to interpret the situation any way they want to.

Anyone can build a radio from basic components which picks up signals from any frequency, or by replacing the crystal in an existing radio. If there is a law that forbids this, then it is conflicting with basic freedoms and it's probably not worthwhile to live in that country.
The arbitrary restrictions of land life are among the prime motivators for sailors to sail! Amen! Amen!

I think a lot of the FCC regs are targeted to sellers/importers/commercial builders, etc. So, if you order something like this from the web, as an individual, I suppose the deal might just fall between the cracks. I don't think they'd carry on with that level of enforcement. Don't take my word for it though! (usual legal disclaimer language goes here). The law's the law - albeit we're not necessarily sure if it applies to the dongles, due to the structure of the reg language. If the devices were not in compliance, and you were to sell them enmasse, you'd be more likely to be questioned about it. That'd especially be true if someone was caught doing something more seriously illegal (actually receiving and decrypting calls), while using a device (purchased from you) to do it.

I still don't know for sure whether or not any of these dongles have built-in blocks for the offending frequencies. I looked at a couple corporate flyers (high-level spec sheets) but the info wasn't there. It could very well be that some of them DO comply with the US regs in this matter. It will take more inquiry. Anyway, I agree with you, it's ridiculous to stomp on simple experimenters (people like you) who are using the devices in a harmless way. Laws should target actual lawbreaking, rather than contruction project pieces.
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Old 17-07-2014, 11:41   #150
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Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

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If anyone finds a dongle that has the 824-900 Mhz range blocked, let me know! I'm interested!
Perhaps you're no longer interested, but I remembered having seen something about chipset/frequency ranges and finally found it:
RTL-SDR compatibility list v.2 [work in progress, please help!] : RTLSDR
rtl-sdr – OsmoSDR
As you can see the listed chipsets all cover the range you wanted blocked.

(had on my tongue to say something about legality, legitimacy and electronic communications after a.D. 2012, but I will not risk offending someone )

I'm not an expert either, but as far as I've understood the chipsets are only tuners with a high bandwidth. It's the software you apply to it that makes it tune, scan, decode or decrypt.
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