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Cool Stuff for Amateur Radio - APRS

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  Cool Stuff for Amateur Radio - APRS Oregonian Haruspex <bob_davis_retired@yahoo.com> - 2014-02-07 15:26 -0800
    Re: Cool Stuff for Amateur Radio - APRS 2phar <none@example.com> - 2014-02-07 18:46 -0500
      Re: Cool Stuff for Amateur Radio - APRS Oregonian Haruspex <bob_davis_retired@yahoo.com> - 2014-02-07 16:13 -0800
        Re: Cool Stuff for Amateur Radio - APRS Massive Unibrow <unibrow@gmail.com> - 2014-02-08 07:52 +0000
          Re: Cool Stuff for Amateur Radio - APRS Oregonian Haruspex <bob_davis_retired@yahoo.com> - 2014-02-08 09:07 +0000
            Re: Cool Stuff for Amateur Radio - APRS RS Wood <rsw@therandymon.com> - 2014-02-08 11:48 +0000
            Re: Cool Stuff for Amateur Radio - APRS 2phar <none@example.com> - 2014-02-08 08:58 -0500
              Re: Cool Stuff for Amateur Radio - APRS Oregonian Haruspex <bob_davis_retired@yahoo.com> - 2014-02-08 15:10 -0800
              Re: Cool Stuff for Amateur Radio - APRS Vince Mulhollon <vincemulhollon@gmail.com> - 2014-02-10 05:41 -0800
          Re: Cool Stuff for Amateur Radio - APRS "Dirk T. Verbeek" <dverbeek@xs4all.nl> - 2014-02-08 12:17 +0000

#91 — Cool Stuff for Amateur Radio - APRS

I'm a radio amateur and have been for about 5 years now.  My radio 
interest started when I was a kid, playing with the shortwave radio 
that my friend's dad owned and later with the cult classic 
long-distance receiver, the GE SupeRadio.  When I was about 13 I got a 
police scanner - this was shortly before the cell phone frequency ban.  
I was also a computer geek at the time and these sorts of interests 
seem to go hand in hand.

When I got my amateur radio license I started looking into the 
different technologies available to the ham.  In addition to typical 
voice and morse code (known to us hams as CW) there are quite a few 
digital communications modes that are in common use, from very low 
bitrate error-corrected communications to fully high speed protocols.  
Today I'd like to share one of these really cool digital protocols / 
modes with you all, in hopes of getting those of you who aren't hams 
interested, and those of you who are interested in it.  The protocol is 
called APRS.  It's a packet communication protocol that is usually 
carried out at 1200 baud.  Messages are forwarded through the network 
until they hit a dead end, and routing information is conveyed by 
beaconing.  If you (A) can see a station (B) that can see another 
station (C), all you do is input the call sign of C and you can send 
them a message with B acting as an intermediary.  Location data, 
temperature, current status, and text messages can be conveyed this 
way.  APRS also has a feature known as the iGate, which is a node 
hooked up to the internet.  With this feature, it is possible to send 
text messages to other hams pretty much anywhere in the world, using 
the internet to bridge any long range gaps.

I often use this technology to send emails to my wife.  She is not a 
radio amateur, so she can not send messages through the APRS network, 
but I can simply send them to her email address and APRS to email 
services (all free, like every amateur radio technology or facility) 
will deliver the mail to her.  I sometimes go hunting or fishing far 
from cell phone service in the real back country in Oregon, but I can 
almost always get APRS packets out to an iGate, or to somebody that 
sees somebody that sees somebody (etc) that can see an iGate.

There are many handheld radios with APRS built in, as well as larger 
units meant for installation in a home or vehicle.  Free computer 
software can also perform all the functions (often even more) done by 
commercial APRS radios so really all one needs is an old computer and 
an old radio to get started.

Thanks for listening, and I will post other periodic neat comments 
highlighting amateur radio tech that I think is cool.

Here are some links to the relevant technologies I mentioned:

APRS, the protocol itself (exhaustive web pages by the man that pioneered it):

http://www.aprs.org

APRS to email:

http://www.aprs-is.net/Email.aspx

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#92

On 2/7/2014 6:26 PM, Oregonian Haruspex wrote:
> I'm a radio amateur and have been for about 5 years now.  My radio
> interest started when I was a kid, playing with the shortwave radio that
> my friend's dad owned and later with the cult classic long-distance
> receiver, the GE SupeRadio.  When I was about 13 I got a police scanner
> - this was shortly before the cell phone frequency ban. I was also a
> computer geek at the time and these sorts of interests seem to go hand
> in hand.
>
> When I got my amateur radio license I started looking into the different
> technologies available to the ham.  In addition to typical voice and
> morse code (known to us hams as CW) there are quite a few digital
> communications modes that are in common use, from very low bitrate
> error-corrected communications to fully high speed protocols. Today I'd
> like to share one of these really cool digital protocols / modes with
> you all, in hopes of getting those of you who aren't hams interested,
> and those of you who are interested in it.  The protocol is called
> APRS.  It's a packet communication protocol that is usually carried out
> at 1200 baud.  Messages are forwarded through the network until they hit
> a dead end, and routing information is conveyed by beaconing.  If you
> (A) can see a station (B) that can see another station (C), all you do
> is input the call sign of C and you can send them a message with B
> acting as an intermediary.  Location data, temperature, current status,
> and text messages can be conveyed this way.  APRS also has a feature
> known as the iGate, which is a node hooked up to the internet.  With
> this feature, it is possible to send text messages to other hams pretty
> much anywhere in the world, using the internet to bridge any long range
> gaps.
>
> I often use this technology to send emails to my wife.  She is not a
> radio amateur, so she can not send messages through the APRS network,
> but I can simply send them to her email address and APRS to email
> services (all free, like every amateur radio technology or facility)
> will deliver the mail to her.  I sometimes go hunting or fishing far
> from cell phone service in the real back country in Oregon, but I can
> almost always get APRS packets out to an iGate, or to somebody that sees
> somebody that sees somebody (etc) that can see an iGate.
>
> There are many handheld radios with APRS built in, as well as larger
> units meant for installation in a home or vehicle.  Free computer
> software can also perform all the functions (often even more) done by
> commercial APRS radios so really all one needs is an old computer and an
> old radio to get started.
>
> Thanks for listening, and I will post other periodic neat comments
> highlighting amateur radio tech that I think is cool.
>
> Here are some links to the relevant technologies I mentioned:
>
> APRS, the protocol itself (exhaustive web pages by the man that
> pioneered it):
>
> http://www.aprs.org
>
> APRS to email:
>
> http://www.aprs-is.net/Email.aspx
>

And Amateur Radio satellites carry APRS stations..  I remember being 
able to relay messages from my TNC to a base in Antarctica via satellite 
back in the 1980s. Wonderful stuff.

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#95

On 2014-02-07 23:46:30 +0000, 2phar said:

> And Amateur Radio satellites carry APRS stations..  I remember being 
> able to relay messages from my TNC to a base in Antarctica via 
> satellite back in the 1980s. Wonderful stuff.

I forgot to mention satellites in this context - good catch!

The murder of Slashdot has gotten me thinking about amateur radio as a 
last-resort non-commercial communications infrastructure.  Amateur 
radio is often mentioned in the context of emcomm, but I think it has 
potential in this increasingly corporate-controlled world we live in as 
a last resort freedom of speech option.

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#109

In article <ld3ss3$rrc$1@dont-email.me>,
 Oregonian Haruspex <bob_davis_retired@yahoo.com> wrote:

> On 2014-02-07 23:46:30 +0000, 2phar said:
> 
> > And Amateur Radio satellites carry APRS stations..  I remember being 
> > able to relay messages from my TNC to a base in Antarctica via 
> > satellite back in the 1980s. Wonderful stuff.
> 
> I forgot to mention satellites in this context - good catch!
> 
> The murder of Slashdot has gotten me thinking about amateur radio as a 
> last-resort non-commercial communications infrastructure.  Amateur 
> radio is often mentioned in the context of emcomm, but I think it has 
> potential in this increasingly corporate-controlled world we live in as 
> a last resort freedom of speech option.

This article I posted on a site I run seems germane:
http://lounge.dictatorshandbook.net/index.php?/archives/94-Dictator-Disli
kes-Shortwave-Radio.html

I'd forgotten in Usenet days you sometimes have to paste the links 
together.  Here's a shortened link in case it doesn't work:

http://goo.gl/JEYNPw

When I was researching in order to write _Dictator's Handbook: a 
practical manual for the aspiring tyrant_ it became clear one of the 
advantages of shortwave and radio in general is that no one can track 
what you - the listener - are tuning in.  Everyone gets excited about 
the Internet (remember the media orgasm over Twitter during the Arab 
Spring?) for subtervention of governments.  But governments have shown, 
from Iran to Syria to China to (obviously) the USA that they can track 
and identify every website you visit.  They can't do that to radio 
waves.  They can try to block the transmission, or going back to WWII 
days, jam it.  But they can't track who is listening to it.

Internet's got a lot of advantages, but radio still has some advantages 
the Internet with which the Internet can't compete.

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#112

Massive Unibrow <unibrow@gmail.com> wrote:

> This article I posted on a site I run seems germane:
> http://lounge.dictatorshandbook.net/index.php?/archives/94-Dictator-Disli
> kes-Shortwave-Radio.html
> 
> I'd forgotten in Usenet days you sometimes have to paste the links 
> together.  Here's a shortened link in case it doesn't work:
> 
> http://goo.gl/JEYNPw
> 
> When I was researching in order to write _Dictator's Handbook: a 
> practical manual for the aspiring tyrant_ it became clear one of the 
> advantages of shortwave and radio in general is that no one can track 
> what you - the listener - are tuning in.  Everyone gets excited about 
> the Internet (remember the media orgasm over Twitter during the Arab 
> Spring?) for subtervention of governments.  But governments have shown, 
> from Iran to Syria to China to (obviously) the USA that they can track 
> and identify every website you visit.  They can't do that to radio 
> waves.  They can try to block the transmission, or going back to WWII 
> days, jam it.  But they can't track who is listening to it.
> 
> Internet's got a lot of advantages, but radio still has some advantages 
> the Internet with which the Internet can't compete.

It is possible for authorities to determine not only that you are listening
to the radio, but also what frequency you are tuned in to.  The Germans had
this technology in WWII, but it was very local and obvious - large detector
vans and trench-coated goons roaming the neighborhoods.  By the time 'Nam
rolled around, this technology had been placed aboard US airplanes which
could detect emissions from local oscillators from many miles away.

Some radios, such as basic crystal sets, that are completely passive, and
direct conversion radios may be immune to detection but I wouldn't bet my
life on it.  Still, detection of radios would be a lot more work than
automated Internet surveillance.

Thanks for the reply.  Your site is interesting.

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#113

On 2014-02-08, Oregonian Haruspex <bob_davis_retired@yahoo.com> wrote:
> Massive Unibrow <unibrow@gmail.com> wrote:
>
>> This article I posted on a site I run seems germane:
>> http://lounge.dictatorshandbook.net/index.php?/archives/94-Dictator-Disli
>> kes-Shortwave-Radio.html
>> 
>> I'd forgotten in Usenet days you sometimes have to paste the links 
>> together.  Here's a shortened link in case it doesn't work:
>> 
>> http://goo.gl/JEYNPw
>> 
>> When I was researching in order to write _Dictator's Handbook: a 
>> practical manual for the aspiring tyrant_ it became clear one of the 
>> advantages of shortwave and radio in general is that no one can track 
>> what you - the listener - are tuning in.  Everyone gets excited about 
>> the Internet (remember the media orgasm over Twitter during the Arab 
>> Spring?) for subtervention of governments.  But governments have shown, 
>> from Iran to Syria to China to (obviously) the USA that they can track 
>> and identify every website you visit.  They can't do that to radio 
>> waves.  They can try to block the transmission, or going back to WWII 
>> days, jam it.  But they can't track who is listening to it.
>> 
>> Internet's got a lot of advantages, but radio still has some advantages 
>> the Internet with which the Internet can't compete.
>
> It is possible for authorities to determine not only that you are listening
> to the radio, but also what frequency you are tuned in to.  The Germans had
> this technology in WWII, but it was very local and obvious - large detector
> vans and trench-coated goons roaming the neighborhoods.  By the time 'Nam
> rolled around, this technology had been placed aboard US airplanes which
> could detect emissions from local oscillators from many miles away.
>
> Some radios, such as basic crystal sets, that are completely passive, and
> direct conversion radios may be immune to detection but I wouldn't bet my
> life on it.  Still, detection of radios would be a lot more work than
> automated Internet surveillance.
>
> Thanks for the reply.  Your site is interesting.

How 'bout this:  Special deal.  Free copies (epub or mobi) of the 350
page _Dictator's Handbook: a practical manual for the aspiring tyrant_
to Slashdot refugees who make the transition to Usenet.  Just send an
email to info@dictatorshandbook.net and mention the top secret code word
"Fuck Beta."

Costs me nothing to offer and it's fun to provide an incentive to
Slashdot Refugees.

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#117

On 2/8/2014 4:07 AM, Oregonian Haruspex wrote:
>
> It is possible for authorities to determine not only that you are listening
> to the radio, but also what frequency you are tuned in to.  The Germans had
> this technology in WWII, but it was very local and obvious - large detector
> vans and trench-coated goons roaming the neighborhoods.  By the time 'Nam
> rolled around, this technology had been placed aboard US airplanes which
> could detect emissions from local oscillators from many miles away.
>
> Some radios, such as basic crystal sets, that are completely passive, and
> direct conversion radios may be immune to detection but I wouldn't bet my
> life on it.  Still, detection of radios would be a lot more work than
> automated Internet surveillance.
>
> Thanks for the reply.  Your site is interesting.
>

I suspect the local oscillator snooping might not be much good with 
software defined radio. There may be similar artifacts, but wouldn't it 
be far more complex?

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#132

On 2014-02-08 13:58:33 +0000, 2phar said:

> On 2/8/2014 4:07 AM, Oregonian Haruspex wrote:
>> 
>> It is possible for authorities to determine not only that you are listening
>> to the radio, but also what frequency you are tuned in to.  The Germans had
>> this technology in WWII, but it was very local and obvious - large detector
>> vans and trench-coated goons roaming the neighborhoods.  By the time 'Nam
>> rolled around, this technology had been placed aboard US airplanes which
>> could detect emissions from local oscillators from many miles away.
>> 
>> Some radios, such as basic crystal sets, that are completely passive, and
>> direct conversion radios may be immune to detection but I wouldn't bet my
>> life on it.  Still, detection of radios would be a lot more work than
>> automated Internet surveillance.
>> 
>> Thanks for the reply.  Your site is interesting.
>> 
> 
> I suspect the local oscillator snooping might not be much good with 
> software defined radio. There may be similar artifacts, but wouldn't it 
> be far more complex?

A direct sampling SDR would do rather well, I think.  It all comes down 
to the threat model - are you existing in a city where there are tens 
or hundreds of thousands of other computers running around the clock?  
Out in the country?  In the woods with a special operations team of 
insurgents?  In the last case I would consider almost every 
communications device to be a giant beacon screaming "DRONE STRIKE ME."

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#194

On Saturday, February 8, 2014 7:58:33 AM UTC-6, 2phar wrote:
> I suspect the local oscillator snooping might not be much good with 
> software defined radio. There may be similar artifacts, but wouldn't it 
> be far more complex?

It would work better than you might think.  You usually end up setting the LO freq maybe 10 or so KHz higher or lower than what you're monitoring.  Or if you're playing dynamic range games to avoid a really strong signal you might tune off quite a ways.  This is assuming a typical superhet architecture.  If you go direct sampling its harder and more expensive and might be harder to monitor.

It boils down to if you're replacing everything after the RF amp you're sorta correct although you're not going to like the price (or likely the performance) and if you're replacing just the product detector or final IF mixer then it'll have no real effect.

For awhile when my R-392 was working I had a 455 KHz SDR listening to the IF.  This would have no effect on DF detection or whatever, but it made a kinda cool demod.  I don't recall how well NBFM on 10 meters worked but I remember trying it.  The latency from twisting the tuning dial to speaker output quickly drove me nuts.

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#116

op 08-02-14 07:52 schreef Massive Unibrow:
> This article I posted on a site I run seems germane:
> http://lounge.dictatorshandbook.net/index.php?/archives/94-Dictator-Disli
> kes-Shortwave-Radio.html
>
> I'd forgotten in Usenet days you sometimes have to paste the links
> together.  Here's a shortened link in case it doesn't work:
>
> http://goo.gl/JEYNPw
As already mentioned in another thread you can easily use long url's by 
embedding them between quotations like:
"http://lounge.dictatorshandbook.net/index.php?/archives/94-Dictator-Dislikes-Shortwave-Radio.html"

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