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Re:Again? by Ol+Olsoc · 2015-04-29 13:31 · Score: 1 · on Ham Radio Fills Communication Gaps In Nepal Rescue Effort

Do we really need stories about rescue efforts after every disaster?

No, but some of us like the news - even that which you find repetitive. I find it interesting that, with all of the modern technologies now available, old-fashioned ham is still useful.

Good reply. But Ham radio has definitely kept up with the times. While the old radios still work - and it's a subset of the hobby, the new stuff like the Software Defined Radio transceivers like the FlexRadios, http://flex-radio.com/ and the various digital/soundcard modes are nothing short of amazing. Geek-A-Licious!

Disclaimer: I'm a zealot.

Re:Different HW Needed? by Muad'Dave · 2012-10-22 04:48 · Score: 2 · on DARPA Funds a $300 Software-Defined Radio For Hackers

That was your use case - for many other uses, YIGs are unneeded - a simple NCO/PLL will work just fine. There are plenty of A/D's that can sample more than 10 MHz at 16+ bits. For the 2.4 GHz use case you would not have to sample the RF signal directly - that would be silly. You would first downconvert the desired signal to a more reasonable IF (intermediate frequency) and then sample that. If you don't have image rejection requirements you could shift it to DC and sample that. Read up on superheterodyne receivers to start with, then digital up- and down-converters.

This company makes the Flex-6000 series Amateur transceivers - they are all digital and directly sample the HF and VHF bands from 30 kHz to 77 MHz continuously. This radio has every bell and whistle, and has incredible performance stats. It's expensive, but it is indicative of the amount of spectrum you can simultaneously sample.

Re:Different HW Needed? by vlm · 2012-10-22 00:50 · Score: 1 · on DARPA Funds a $300 Software-Defined Radio For Hackers

This is why $300 is cheap for an SDR; but $30 is expensive for a wifi dongle.

$21 is cheap for a SDR... kit. I built this one for 30M band back when it was about $12. If you are lucky you can get the correct assembled TV dongle off ebay for $10 or so.

http://fivedash.com/

At the other end, if you'd like to spend four figures for cutting edge performance, there's always

http://www.flex-radio.com/

American Amateur Radio Equipment Companies by dtmos · 2010-04-06 11:20 · Score: 2, Interesting · on Ham Radio Still Growing In the iStuff Age

The resurgence of American amateur radio equipment companies is one of the great untold stories recently. I mean, one still has Japanese industry stalwarts Icom and Kenwood, who led the Japanese domination of the industry in the 1970s, but even Yaesu was bought by Motorola a few years back. The real news, though, is the new, innovative startups, doing state-of-the-art, truly wonderful designs, with simultaneous high performance, high quality, and reasonable prices. Companies like Elecraft and software-defined radio pioneer FlexRadio Systems come to mind, producing products unmatched by any of the mainstream companies.

It's a refreshing change.

Re:no kidding by vhfer · 2009-02-03 08:15 · Score: 1 · on Students Call Space Station With Home-Built Radio

Indeed, one can purchase a few vital components (boards) and create a SDR (software defined radio) and from there, you write your own radio, as in code. Here's one http://www.linuxdevices.com/news/NS3911104852.html for US $85k. Too much? Try this: http://www.flex-radio.com/ where you'll find lots of options.

Re:Closed drivers by Zymergy · 2007-12-12 14:02 · Score: 1 · on Intel Demos Software Defined WiFi/WiMAX/DVB-H Chip

Software controlled radios are becoming the new big thing for HAMs also. Any plans to write more 'flexible' software for the FLEX-5000A radio?
http://www.flex-radio.com/
Icom also has a neat receiver-only radio: http://icomamerica.com/en/products/receivers/pc/pcr2500/default.aspx

Re:A plug for GNU Radio by leighklotz · 2006-02-03 12:19 · Score: 2, Informative · on Software-Defined Radio Could Unify Wireless World

Why spend that much ($350+), when you can order a dirt-cheap shortwave radio for maybe $40 and just use a simple 455 kHz to 12 kHz adaptor?

SDR is a broad topic. Wide-band digital modes such as the 12KHz wide DRM or even narrow ones such as HamDream are a simple example.

SDR involves a variety of techniques, but the basic idea is using an A/D at an early stage, and performing operations traditionally done with RF components with DSP software instead.

In its extreme, an SDR has a broadband RF amplifier and a DSP.

Some systems use a tuned RF filter before the RF amplifier to improve dynamic range and reduce overload, and others put the DSP after the first analog mixer. Ham equipment that uses IF DSP does this, such as many of the ICOM radios.

Then there are devices that then mix down to somewhere around the audio range, at least to the 0-96KHz or 0-48KHz range handled by many popular PC sound cards. The RF signal is detected by a an I-Q detector, which produces two signals In Phase and Quadrature (90 degrees out of phase). You might notice that this is a decomposition of a periodic wave into real and complex parts, given v=cos(omega)+j sin(omega). Thus, DSP techniques such as FFT can be applied in the complex domain. If you're seriously interested in this math, look up the Hilbert transform. It lets you modulate or demodulate directly in the DSP, and as a result the transmit and receive software and hardware are very similar. (And wouldn't the Professor on Gilligan's Island like to know that you can make a receiver into a transmitter without using coconuts!)

Anyway, once you get the I-Q signals into the two channels of the sound card, you get a view of the RF spectrum all at once, up to the bandwidth of your sound card sampling. So, if you have a 48KHz sound card you get 48KHz of band scanned simultaneously, and can pick and choose what frequency you want to demodulate, and how you want to demodulate it in software (AM, Single-Side Band, FM, various digital modes such as the aforementioned DRM=digital radio mondial). See here and here.

The SoftRock 40 and its replacement, the SRv5, surface mount kits costing in the $30 range, do this. They're an excellent introduction to SDR techniques, without requiring DSP chip programming. People are doing fun things with them. It's not a transmitter yet, but it will be soon with another board and a ham license).

For software, among others, there is Gnuradio, and also SDRadio, a Windows app. And there's DTTSP, a SourceForge project that runs in Linux and also releases a DLL used by the FlexRadio people. DTTSP has a number of front ends in development, in Java and other languages.

A step up is the FlexRadio SDR-1000, alluded to above. It's a 100W transceiver that does the same thing that the SoftRock does, but does a better job, and also use a VFO that allows it to pick what frequency range it operates on, rather than being limited to a particular crystal-controlled band as the stock SoftRock does. It also costs quite a bit more, and they use a 96KHz sound card to get good quality.

A few interesting things by leighklotz · 2005-09-21 11:01 · Score: 1 · on Emergency Gadgets Reviewed

Here are a few things that might be interesting to people under 70:

Flex Radio by leighklotz · 2004-12-27 11:08 · Score: 1 · on Universal Software Radio Peripheral From GnuRadio

See also Flex-Radio which can transmit (if you have a license), has a similar price point (within 3dB ;-), works with GnuRadio software, and comes with its own Visual Basic software (source).

Flex Radio by leighklotz · 2004-12-27 11:08 · Score: 1 · on Universal Software Radio Peripheral From GnuRadio

See also Flex-Radio which can transmit (if you have a license), has a similar price point (within 3dB ;-), works with GnuRadio software, and comes with its own Visual Basic software (source).

Re:Ah yes but by plcurechax · 2004-12-27 06:43 · Score: 1 · on Universal Software Radio Peripheral From GnuRadio

you could use this hardware to pull in terrestrial HDTV.

You could, but you would be better off using the pcHDTV HD-3000 card which is designed to work well with terrestial, aka Over The Air (OTA), HDTV, "legacy" NTSC, and can legally ignore the FCC Broadcast Flag until June 2005.

To clarify, GNU Radio is a Free Software software defined radio implementation, and the USRP (Universal Software Radio Peripheral) is the semi-official reference hardware platform designed by Matt Ettus. The USRP is real-life useless without additional modules for basicRX (receiver) and/or basicTX (transmitter). Depending on the usage, you might require a up/down converter aka a transverter.

There are others working on similar hardware (e.g. SSRP for a bit simpler and lower cost, or the amateur radio oriented Flex-Radio) as well, and I expect that the USRP hardware will be copied, cloned, and improved upon in a short time.

Re:Sweet ! by John+Miles · 2004-12-27 06:38 · Score: 3, Informative · on Universal Software Radio Peripheral From GnuRadio

What you're talking about already exists, actually. See www.flex-radio.com.

Ham Radio in a Changing Electronics Landscape by ltkije · 2004-11-11 16:40 · Score: 1 · on Ham and Software - Communities of Creativity?

Going to the Dayton Hamvention this year after a 20 year absence was eye-opening. There just weren't many people under 50 to be seen.

I think several trends are at work in amateur radio right now. First is that advances in chip integration have made it more difficult to homebrew equipment. There are fewer and fewer "catalog" parts around with simple functions. This, plus surface mount packaging, have made electronic products cheaper but electronic experimentation much more difficult for the average person.

Another trend is the commercial annihilation of distance. Talking across the country on two-way radio loses its thrill when one can do the same on a cell phone more or less for free, and much more reliably.

Software Defined Radio (SDR) is a bright spot in ham radio today. Forget about the Big Project flavor of Gnu Radio. Amateur SDR projects tend to be quite simple - sometimes ingeniously so - and approach the subject from the experimenter's point of view, not the engineer's. Most are based on the simple proposition that a recent commodity PC plus sound card make a pretty decent digital signal processor.

Organizations like ARRL and TAPR have encouraged digital radio up to and including SDR, though they have each tried to firmly guide the direction of amateur SDR. In fairness, ARRL has published many articles in its experimenter's magazine and in an excellent online compendium.

Two independent projects show the range of amateur SDR. The SDR-1000 is a hardware/software project turned semi-commercial, with a steep price of entry. Flex Radio Systems also has a unique definition of Open Source. On the other hand, the SDRadio project is an independent software receiver that is slowly morphing into a community effort. The project forum is brimming with good ideas.

There are other, loosely related projects such as narrowband signal processing and Digital Radio Mondiale (broadcast) decoders being done by hams. From these resources it's easy to see SDR as an emerging force in rejuvenating ham radio, even though today the various efforts are quite fragmented.