While a relatively newly licensed amateur radio operator (got my license earlier this year), I've been a radio enthusiast for well over 25 years (since I was around 10 years old). I have had many scanners, shortwave radios, and even owned an HT that operated on ham bands (but never transmitted). In the 90s
I would decode POCSAG (pager) transmissions over local airwaves using a scanner
or the ham radio with a discriminator output wired up to the soundcard of a Windows PC.

Flash forward to today -- I've been doing a whole lot of digital modes lately. I still appreciate analog (and I always will), but digital modes are a lot of fun. Unfortunately, they're still insanely finicky, and it truly feels amateur.
Though we're definitely seeing some activity by the amateur community at large,
and support for it grows daily (with digital implementations by commercial vendors using DRM, D-Star, WIRES, etc).

APRS seems to be fueling a lot of the interest (though I personally don't care for it much, as it seems so automated and somewhat unnecessary), which is built
on top of AX.25 (the basis for packet).

I've been doing a lot of SDR stuff lately. I have a whole variety of SDRs. Several cheap R820T based RTL-SDR's, a FunCube Dongle+, and a "very wide receiver" from Russia offering higher fidelity and full range reception without
needing a convertor.

For the last few weeks I've been tinkering with Raspberry Pi B+ and BeagleBone Black as a demod/decode host, powering RTL-SDRs to decode a variety of signals.
I've come to terms with the fact that these small ARM platforms are not powerful enough to decode much of anything without having issues.

ADS-B (aircraft surveillance) decodes nicely, and my Raspberry Pi B+ and RTL-SDR with stock junk antenna have been going at it since the last few days. It has a terrible reception range since I'm using the stock antenna and I am on
the first floor of a two story building... indoors. But I have an ADS-B tuned antenna on the way. I'm then feeding this data off to flightradar24.com, who then in exchange gives me a free Premium account to view live aircraft traffic throughout the world.

I had hopes to build a cluster of embedded devices with SDRs and then build some control software (to allow me to easily scan the airwaves, hook in to automatically decode some signals, and stream audio content ala WebSDR), but these ARMs are just too damn slow to be much use. I'm currently looking into acquiring some ODROID U3's and see how much more they can handle.

If all things pan out, I expect to make a small iOS app that let's me control the small cluster, stream the audio, and review decode logs -- the ultimate in lightweight mobile SDR ability.

Just thought I'd share...

Knight

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þ Synchronet þ The Phunc BBS -- Back from the dead! -- telnet to bbs.phunc.com

.

Just thought I'd share...

Knight

All of that...is pretty freakin' cool.

**********************
* Tim Wray, Sysop *
* Backwood Realm BBS *
* Bedford, Indiana *
* bwrbbs.dddns.net *
**********************

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þ Synchronet þ The Backwood Realm BBS - bwrbbs.ddns.net - The heart of Southern Indiana

Re: SDR and Digital Mode Decoding
By: Knight to All on Tue Nov 04 2014 15:35:27

I wish I had time to give this a more in depth reply right now, but thank you for mentioning those experiences, at the very least. There's absolutely nothing that is going to keep me back from pursuing this interest more, especially now that you've mentioned all of those wonderful little gems. :) I'd love to hear more specifics if you ever have time and feel like digressing a bit.
Hell, I've got a few ideas for 'droid apps of my own lately, too. If you need any help on the mundane aspects of the app coding, once I'm starting to learn the general APIs, let me know. I need practice.

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þ Synchronet þ Tinfoil Tetrahedron BBS telnet or ssh -p 2222 to tinfoil.synchro.net

Re: Re: SDR and Digital Mode Recording
By: Khelair to Knight on Wed Nov 05 2014 01:29 pm

I wish I had time to give this a more in depth reply right now, but thank you for mentioning those experiences, at the very least. There's
absolutely nothing that is going to keep me back from pursuing this
interest more, especially now that you've mentioned all of those wonderful little gems. :) I'd love to hear more specifics if you ever have time and feel like digressing a bit.

That's great to hear. I think the hobby is more alive than ever. There's just so much to do. Analog repeaters (the classic portion of the hobby), digipeaters, internet repeater linking, FreeDV (digital voice over VHF/UHF and HF, using extremely narrow bandwidth and gracefully degrades when data is missing), satellite repeaters, contests galore, SOTA (summits on the air), POTA
(parks on the air), packet BBSes, Broadband Hamnet (amateur licensed wifi mesh over extended distances), etc.

Exciting times. I thought things were neat when it was all analog when I was 10
years old and an avid scanner listener. Years later I'm finding that there's not shortage of things to touch.

Hell, I've got a few ideas for 'droid apps of my own lately, too. If you need any help on the mundane aspects of the app coding, once I'm starting
to learn the general APIs, let me know. I need practice.

Thanks for that offer! I think it would come in handy -- and any others who think they want to jump in are welcome too. My particular sets of "ready now" skills include backend development (variety of languages and frameworks), API design, architecture, infrastructure, and iOS development. Constantly working on additional skills (I make sure to do one lesson a day online), especially around design, user experience (UX), etc.

But, there's too much to do for me to tackle alone. What's your droid development experience so far? (A nice first goof around could be to develop an
Android client for http://radioworld.me since it's relatively straight forward and would serve as a basis for future work, if you were interested).

To a continued excitement in the hobby,


Knight

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þ Synchronet þ The Phunc BBS -- Back from the dead! -- telnet to bbs.phunc.com

Re: Re: SDR and Digital Mode Recording
By: Knight to Khelair on Thu Nov 06 2014 03:31:57

That's great to hear. I think the hobby is more alive than ever. There's just so much to do. Analog repeaters (the classic portion of the hobby), digipeaters, internet repeater linking, FreeDV (digital voice over VHF/UHF and HF, using extremely narrow bandwidth and gracefully degrades when data is missing), satellite repeaters, contests galore, SOTA (summits on the air), POTA (parks on the air), packet BBSes, Broadband Hamnet (amateur licensed wifi mesh over extended distances), etc.

Yeah I've really never heard many of the things beyond the TV app that echicken and [I think] you were discussing, barring packet BBSing, that HAM is capable of. The breadth of technologies really surprised me, though it shouldn't have, in hindsight. I've absolutely got to get into it. Soon as I've got money earmarked for a new apartment for my son & I, I'm dedicating some to that.

Exciting times. I thought things were neat when it was all analog when I was 10 years old and an avid scanner listener. Years later I'm finding that there's not shortage of things to touch.

I think that's part of the reason that I was so amazed when I saw the initial list of things that you'd been speaking of. I remember from Jr. High/middleschool talking with some HAM technology afficianados that I knew about some of the data capabilities, but they were only just starting to realize what kinds of things they were stumbling across, themselves. I haven't had much contact with people in the know on such since then, unfortunately. Honestly, though, with my focus on disaster preparedness and the like, I've got plenty of reason to get into this even without such things, but the capabilities for a mobile communication hub with everything that you've described are kind of mindboggling right now. I'm going to have to start compiling information on my wiki right quick here. ;)
Shit, I actually got to that before I started in on replying to the next section. ;)

Thanks for that offer! I think it would come in handy -- and any others who think they want to jump in are welcome too. My particular sets of "ready now" skills include backend development (variety of languages and frameworks), API design, architecture, infrastructure, and iOS development. Constantly working on additional skills (I make sure to do one lesson a day online), especially around design, user experience (UX), etc.

But, there's too much to do for me to tackle alone. What's your droid development experience so far? (A nice first goof around could be to develop an Android client for http://radioworld.me since it's relatively straight forward and would serve as a basis for future work, if you were interested).

My focus in the past has been completely on back-end development. I mean I've touched UX code a little bit, but I just have a bad grasp on aesthetics in general. I only learned to dress myself without standing out horribly a few years back here. I've started delving into some intro-level algorithms courses, but that's about it. I mean I'm hardly a seasoned coder, but I know how to write in a half a dozen languages and I can write some good system/ network adminning scripts. My first fully-fledged project that I've been working on in quite awhile here is the vDOC command shell clone for Synchronet, actually. It should be up in an alpha version within a week or two, so long as work doesn't leave me too terribly exhausted every night.
I wouldn't mind being tossed some small, light-weight stuff, though, primarily because I want to learn to develop for Android (my experience on that platform so far is precisely none), and I really need to work on getting better at learning via API docs better. That's pretty much the name of the game when getting development jobs with established code bases, and even open source, and they're still a little bit foreign to me, so I just want to broaden my experience learning on my own as such.
Anyway, I'll write some more later, I'm expecting a phone interview call on a DevOps job in about -5 minutes here. Hopefully they don't leave me hanging!

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