Welcome to the World of Software Defined Radio

However the high cost SDR will kick the butt of high cost analog rigs.

I'm a dabbler and I came across a very cool project that seemed a bit out of my league at the moment - but perhaps you and others on this thread will get a kick out of:

https://ocw.mit.edu/resources/res-ll-003-build-a-small-radar...

Basically, making your own radar system with Coffee cans. As a newbie, I'm a bit surprised by all the modular components that were just fitted together. I knew about Amps and attenuators but didn't know you could get VCOs and mixers like that too. Any books/website recommendations/beginner projects would be appreciated!

The Pirates using FLTSATCOM aren't Brazilian criminal gangs, they are truckers, families, and others who have used rudimentary technology to keep in touch with one another. Think CB radio from the 70's and 80's in the United States.

I've only heard casual conversation between truckers and families on UHF Satcom.

I'm a noob and yeah antennas seem crucial. I wish there was some book I could read on the subject or some recommended websites. Maybe HN can recommend something. There are many tutorials how to build an antenna for specific purpose, but I'd like to gain some basic understanding of how do you design it.

> criminal gangs

or unregistered companies operating under hostile conditions created by the government?

So are you referring to American arrests? Because you make it sound like the Brazillians don't get arrested.

A reply comment says that truckers are using it - what's their legal status?

This is a super cool application for this, unfortunately our water meters and stuff in the UK are very basic mechanical devices in most cases still which sucks so none of this fun for me... This does remind me I probably should check out a few other things though, such as ZigBee protocol on my home automation stuff.

433mhz is used in place of the 900mhz broadcasts in Australia

From that project you linked, it decodes "Oregon Scientific Weather Sensor" protocol - but there's several different versions of that. I'll have to have a play with it one day - thanks!

What do your electric/water meters sound like?

I can't recommend those videos enough, great stuff!

I'll add some other software recommendations along the more visual route. For those on Windows, SDR# [1] is pretty great. On Linux and Mac, I really enjoy using GQRX [2]. And finally, when you're digging deep down into a received signal, inspectrum [3] can't be beat.

[1] http://airspy.com/download/ [2] http://gqrx.dk/ [3] https://github.com/miek/inspectrum

Yeah, it's full of cool stuff. Like old guys talking about emergency systems over VHF/UHF repeaters. And younger people, too.

What many people don't realize is that right now, as you're reading this, you're probably using radio. Either wifi or 4G cellphone. Seems like an obvious statement, but RF engineers have done such a great job at making IP over the air reliable with 802.11X and 4G/LTE that we can forget about the fact that we're using it.

The problem with this though is security. We tend to focus as security engineers too much on stuff riding on top of IP and forget about the underlying layer 1 protocols. And so that's for me what makes radio really interesting - especially dark corners that haven't been looked at for some time because they've been forgotten about.

While not SDR, there are some cheaper alternatives if you're just looking to mix code and radio transmitting.

[1] https://www.adafruit.com/products/3076 [2] http://www.ebay.com/itm/162086931088

Isolated Audio card & PPT signal + HT can probably be done for less than $100 if you go with one of the cheaper HTs.

Heck you can pick up a Mobilinkd[1] for ~$60 if you just want to stick with KISS/AX.25 over Bluetooth. They're really awesome little devices for what they do.

[1] - http://www.mobilinkd.com/

Yes that's about right. For technician's 2 meters and 70cm are by far the most popular. Just tune into a local repeater using a $50 handheld and you can chat all day. You can also use echolink and IRLP to chat world-wide via your local repeater or even connect to a repeater from your smartphone or PC.

I could only dream of having this in my thinkpad able to do some cool mesh networking/APRS strait in my machine.

Generally favorably, most of the mid-high end HF rigs are about 50% SDR based anyway.

As far as I can tell the average user doesn't tinker with them much however.

It depends on who you ask.

The younger generation who have ECE/CS degrees love SDR. So does the military and the commercial/corporate radio industry. Some of the older generation frown upon SDR as voodoo magic with too many computer/network dependencies.

There is a general distrust (among older hams) of computer/network technology and especially anything that depends on a non-human (computer program) to modulate or demodulate a message.

For example, you can send Morse Code with a Carrier Wave and a simple switch (on and off) that you built from wood scraps and copper. You don't need an external thing (program, software, device, etc.) to do that for you. So there are less dependencies and in general it is much simpler to reason about and use. When the shit hits the fan, you want simple, reliable things.

The problem is, most humans don't know Morse Code. So they can't decode a message anymore. Thus the reliance on computers and software.

The efficiency gains are hard to argue with as well. You can do things with SDR that would be impossible or far too costly in hardware... Like resurrecting and communicating with a 36 year-old satellite http://www.rtl-sdr.com/rebooting-isee-3-usrp-software-define...

There is no unity, which is good. Its just like the conversion from AM to SSB or incentive licensing or FM repeaters on 2M in the 70s or no-morse-code licensing or dstar or thru-hole to SMD or rtty to PSK31 or pretty much everything that's ever happened to ham radio ...

Never heard of it. That's crazy. I think its interesting or it'll be the death of the hobby (depending solely on if the participant is personally involved). Its the same stuff looked at differently. We've always all been a fan of that since its start. So obviously I've dropped the docs on me being eligible for QCWA and 3rd gen ham.

I will say as having fooled around with it, latency can sometimes be truly awful which has quite an impact on your normal half duplex operation, ops almost willfully don't understand scalability of the software with bandwidth or real time RTOS desires. Nothing funnier than a PC crash in the middle of a QSO. Ability to "do ham radio stuff" does not necessarily come with basic computer competence, although it often does...

There's a big impedance jump going from "I downloaded HPSDR and it worked" to "I pkg install'd gnuradio and made my own broadcast FM receiver and it worked". Its like using Scratch to write hello world vs porting Emacs to Haskell. The first time you get gnuradio to work its a rush. I imagine the jump from gnuradio to FPGA based boards is similar rush if you can do it. In my infinite spare time...

Good SDRs have overwhelmingly better performance than all but the most expensive traditional superhet receivers. Even then, the exotic superhet receivers match rather than beat equivalent SDRs. Direct conversion receivers are exceptionally good at isolating weak signals that are close in frequency to strong signals, which is a particularly important trait in amateur radio operation. This is widely understood and largely uncontroversial.

Some amateur SDRs are essentially computer peripherals, but they increasingly look just like traditional transceivers. The Icom IC-7300 was the most talked-about transceiver of 2016; It operates like a traditional transceiver and costs about the same, but has exceptional receiver performance and a host of DSP-based bells and whistles. I expect that many Elecraft customers are completely unaware that they bought an SDR rather than an analog transceiver.

Personally, I would never go back to a superhet receiver. If you use a good SDR for half an hour, you're spoiled for life. Superhet receivers still have a place at the low-end of the market, but they're being slowly squeezed out.

Ham here. WT1J. I chat with quite a few hams that run the entire age spectrum. Young and old are into SDR. The older hams use everything from super expensive commercial SDR's that come with rack mountable hardware to Ham Radio Deluxe. The younger hams use RTL-SDR and HackRF along with the pricey gear.

It really depends what you're doing. If you're contesting on RF for example, you'll find younger european hams that have HUGE budgets and build enormous multi-band yagi antenna towers and use very expensive SDR's to monitor the whole band and for excellent RX and signal discrimination capability.

Then you've got the SIGINT crowd that hang out at defcon and they'll generally use cheaper SDR's with bleeding edge software.

The HF band ragchew crowd tend to use boat anchors (old ham radios) with big amplifiers up to legal limit (1.5kw) and hang out especially on the lower frequencies like 7mhz, 3mhz and 1.8mhz. (40m, 80m, 160m in ham speak).

But generally once you get into radio you realize it's less about the base station and more about the antenna.

I ignore it as my escape from the daily grind of computing is digging the soldering iron out and building some very minimal kit out of only discrete components. There is something fascinating about extreme minimalism. The fact it transmits and receives is a byproduct of the journey. I'm unsociable enough to confirm a couple of contacts and then build something else.

I have no problem with SDR, it just doesn't interest me. You need a physical connection with the universe sometimes.

Yes, and contrary to the article it has a google maps display, too. Try "./dump1090 --net --interactive" and open localhost:8080. Would be neat if it could query some API to find out the flight's origin and destination, etc (flightradar24 maybe? do they have an API?)

The cheap RTL_SDR dongles are actually sold as OTA TV tuners. It's how I watch TV.

I look forward to seeing some end-user reviews of this device when it finally ships. I realise that there are plenty of pre-production reviews, but I believe that the final version will have broader matching networks, facilitating better sensitivity on HF and low VHF.