Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 16-07-2014, 13:16   #136
Registered User
 
boat_alexandra's Avatar

Join Date: Aug 2009
Location: chesapeake bay
Boat: bristol 27
Posts: 2,811
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by larsed View Post
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.
__________________

__________________
boat_alexandra is offline   Reply With Quote
Old 16-07-2014, 14:29   #137
Registered User
 
larsed's Avatar

Join Date: Feb 2013
Location: Stockholm, Sweden
Boat: 1911, 6mR, 31 ft
Posts: 76
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by boat_alexandra View Post
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
Lars
__________________

__________________
larsed is offline   Reply With Quote
Old 16-07-2014, 14:34   #138
Registered User
 
Sailor_Hutch's Avatar

Join Date: Nov 2012
Location: Dreaming - through the bars to the Chesapeake... Land cabin: near Raleigh, North Carolina
Posts: 461
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by boat_alexandra View Post
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.
__________________
Sailor_Hutch was born for water. His 130 pounds, well insulated, floats like a bouy. With webbed paws, he gracefully paddles - The Umbrella Man.
Sailor_Hutch is offline   Reply With Quote
Old 16-07-2014, 14:54   #139
Nearly an old salt
 
goboatingnow's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Posts: 13,649
Images: 3
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by boat_alexandra View Post
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
__________________
Check out my new blog on smart boat technology, networking and gadgets for the connected sailor! - http://smartboats.tumblr.com
goboatingnow is offline   Reply With Quote
Old 16-07-2014, 15:06   #140
Registered User
 
Sailor_Hutch's Avatar

Join Date: Nov 2012
Location: Dreaming - through the bars to the Chesapeake... Land cabin: near Raleigh, North Carolina
Posts: 461
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by goboatingnow View Post
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.
__________________
Sailor_Hutch was born for water. His 130 pounds, well insulated, floats like a bouy. With webbed paws, he gracefully paddles - The Umbrella Man.
Sailor_Hutch is offline   Reply With Quote
Old 16-07-2014, 15:33   #141
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,399
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.
Sean Depagnier's Plugins
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:
New rtlsdr Plugin

We would very much like to have some users test this with dongles!!!
__________________
rgleason is online now   Reply With Quote
Old 17-07-2014, 07:23   #142
Registered User
 
Sailor_Hutch's Avatar

Join Date: Nov 2012
Location: Dreaming - through the bars to the Chesapeake... Land cabin: near Raleigh, North Carolina
Posts: 461
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.
__________________
Sailor_Hutch was born for water. His 130 pounds, well insulated, floats like a bouy. With webbed paws, he gracefully paddles - The Umbrella Man.
Sailor_Hutch is offline   Reply With Quote
Old 17-07-2014, 08:04   #143
Registered User

Join Date: Dec 2013
Posts: 209
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.

Sent from my SCH-I415 using Cruisers Sailing Forum mobile app
__________________
wellin is offline   Reply With Quote
Old 17-07-2014, 08:12   #144
Registered User
 
Sailor_Hutch's Avatar

Join Date: Nov 2012
Location: Dreaming - through the bars to the Chesapeake... Land cabin: near Raleigh, North Carolina
Posts: 461
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by wellin View Post
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.

Sent from my SCH-I415 using Cruisers Sailing Forum mobile app
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.
__________________
Sailor_Hutch was born for water. His 130 pounds, well insulated, floats like a bouy. With webbed paws, he gracefully paddles - The Umbrella Man.
Sailor_Hutch is offline   Reply With Quote
Old 17-07-2014, 08:42   #145
Registered User

Join Date: Dec 2013
Posts: 209
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.

Sent from my SCH-I415 using Cruisers Sailing Forum mobile app
__________________
wellin is offline   Reply With Quote
Old 17-07-2014, 08:50   #146
Registered User
 
Sailor_Hutch's Avatar

Join Date: Nov 2012
Location: Dreaming - through the bars to the Chesapeake... Land cabin: near Raleigh, North Carolina
Posts: 461
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by wellin View Post
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.

Sent from my SCH-I415 using Cruisers Sailing Forum mobile app
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.
__________________
Sailor_Hutch was born for water. His 130 pounds, well insulated, floats like a bouy. With webbed paws, he gracefully paddles - The Umbrella Man.
Sailor_Hutch is offline   Reply With Quote
Old 17-07-2014, 09:52   #147
Registered User
 
Sailor_Hutch's Avatar

Join Date: Nov 2012
Location: Dreaming - through the bars to the Chesapeake... Land cabin: near Raleigh, North Carolina
Posts: 461
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.
__________________
Sailor_Hutch was born for water. His 130 pounds, well insulated, floats like a bouy. With webbed paws, he gracefully paddles - The Umbrella Man.
Sailor_Hutch is offline   Reply With Quote
Old 17-07-2014, 10:12   #148
Registered User
 
boat_alexandra's Avatar

Join Date: Aug 2009
Location: chesapeake bay
Boat: bristol 27
Posts: 2,811
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.
__________________
boat_alexandra is offline   Reply With Quote
Old 17-07-2014, 12:17   #149
Registered User
 
Sailor_Hutch's Avatar

Join Date: Nov 2012
Location: Dreaming - through the bars to the Chesapeake... Land cabin: near Raleigh, North Carolina
Posts: 461
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by boat_alexandra View Post
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.
__________________
Sailor_Hutch was born for water. His 130 pounds, well insulated, floats like a bouy. With webbed paws, he gracefully paddles - The Umbrella Man.
Sailor_Hutch is offline   Reply With Quote
Old 17-07-2014, 12:41   #150
Registered User
 
larsed's Avatar

Join Date: Feb 2013
Location: Stockholm, Sweden
Boat: 1911, 6mR, 31 ft
Posts: 76
Re: Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !

Quote:
Originally Posted by Sailor_Hutch View Post
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.
__________________

__________________
larsed is offline   Reply With Quote
Reply

Tags
ais, cheap

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 08:21.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.