Software defined radio - Page 1
Forum section: electronics / general

author: chandin
author_rank: Contributor
timestamp: July 19, 2011, 10:38:37 am
content: Does anyone have any experience with these?I'm looking for a kit to start off with, something less than 200 bux (Hopefully transciever)?All the ones i checked were pretty expensive or the project dosent exist anymore.Maybe dave should do an episode on it hhmmmmmm?

author: Sionyn
author_rank: Frequent Contributor
timestamp: July 19, 2011, 11:32:49 am
content: yes i know bits but a very kewl girl who knows much more

author: chandin
author_rank: Contributor
timestamp: July 19, 2011, 12:08:17 pm
content: Quote from: Sionyn on July 19, 2011, 11:32:49 amWoW thats a mad find, cheers.

author: chandin
author_rank: Contributor
timestamp: July 19, 2011, 12:19:26 pm
content: I found thishttp://gnuradio.orgBut the hardware for that is well over 500bux

author: rf-loop
author_rank: Super Contributor
timestamp: July 19, 2011, 02:20:08 pm
content: If want seriously hobby normal DX or Utility stations:Imho SDR-IQ is guite good.But if want nearly as state of art (in serious hobby class) receiver thenhttp://www.microtelecom.it/perseus/This beats most of available other SWR's.Both of these are not very cheap, but they are not toys. Specially Perseus is amazing good if look specs and if also looks others than manufacturer tests.Of course there are military machines and then some like really for high level professionals High-End receivers or tranceivers but many peoples want more buy good nice house than only one radio.

author: gregariz
author_rank: Frequent Contributor
timestamp: July 19, 2011, 06:59:57 pm
content: Here is a nice kit and series of articles that will explain the inner workingshttp://www.elektor.com/magazines/2007/may/software-defined-radio.91527.lynkxMost SDR's that the ham guys use (and as in jeri's video) use a simple front end (ie RF amp/mixer/local oscillator) that outputs the RF in terms of I&Q signals. These are sampled by the soundcard in the PC and then software is used to demodulate that. Jeri used programmable logic instead of a PC. AM is an easy sqrt(I^2+Q^2). Theres lots of software that does this and a lot more on the Ham sites. A popular one is Power SDRhttp://www.flex-radio.com/products.aspx?topic=powersdr1x

author: Sionyn
author_rank: Frequent Contributor
timestamp: July 19, 2011, 09:00:53 pm
content: tryhttp://www.winrad.org/

author: gregariz
author_rank: Frequent Contributor
timestamp: July 19, 2011, 09:42:31 pm
content: There's lots of software that has been available for the last 10 years. A few of the older ones don't even use I&Q, just magnitude data on one channel is fine for AM. The front ends for that are even simpler, just a traditional mixer.As you'll see in Jeri's video.. the front end hardware can be very simple. Have a look herehttp://www.qrz.lt/ly1gp/SDR/If you have an Oscillator you can simply pump that in as the LO, allowing you to tune across the band or interest or instead or you can use a crystal locked version. The commercial version usually have a digitally controlled synthesizer that can be controlled from the PC software.

author: sacherjj
author_rank: Frequent Contributor
timestamp: July 20, 2011, 02:10:06 pm
content: With the newer DDS chips you can make a nice 3-60 MHz VFO for these for under $30-40.

author: gregariz
author_rank: Frequent Contributor
timestamp: July 20, 2011, 05:03:34 pm
content: The DDS-60 kit is a very popular one for some years that does exactly that...For newbies who just want to try SDR's out though they can just keey it simple use a front end and some software. Everyone has their favourite implementations.

author: sacherjj
author_rank: Frequent Contributor
timestamp: July 20, 2011, 05:29:49 pm
content: Quote from: gregariz on July 20, 2011, 05:03:34 pmHadn't heard of that kit. Adding a link for those interested:http://midnightdesignsolutions.com/dds60/index.htmlI ordered one to play with. Also gives me a function generator past my current 3 MHz limited one.

author: gregariz
author_rank: Frequent Contributor
timestamp: July 20, 2011, 06:39:48 pm
content: Quote from: sacherjj on July 20, 2011, 05:29:49 pmIt'll go beyond 60Mhz ... it samples at about 180MS/S. I find it goes up to about 80 or 90MHz IIRC.. been a while since I played with it. The same kit was available for years before using the AD9850 (same pinout as the 51). They used to call it DDS30 as it was a 30MHz unit. I can't remember if you need to supply the DDS chip or not but I had some 9850's in my racks so I simply placed one of those instead on one of them. Search around the net... people are selling controller boxes etc for that kit that you simply can plug it into to use as a VFO

author: sacherjj
author_rank: Frequent Contributor
timestamp: July 20, 2011, 06:50:27 pm
content: Quote from: gregariz on July 20, 2011, 06:39:48 pmThey are offering a single chip along with the kit for $20 or so. This is about 30% less than buying a one of from Digikey. They will only sell 1 with a kit.

author: updatelee
author_rank: Contributor
timestamp: July 20, 2011, 06:58:49 pm
content: If you want a kit look into the softrock models. If you want a ready made solution for under $200 look at the funcubedongle.I have a funcube and its a slick little unit for the price. I also have a ettus USRP N210 but thats $1700 before frontend's

author: sacherjj
author_rank: Frequent Contributor
timestamp: July 20, 2011, 07:19:42 pm
content: Also, chatting with Jeri on Twitter today, she is going to be working on a transmit chain to her SDR receiver. Those will also be some interesting videos, I'm sure.

author: gregariz
author_rank: Frequent Contributor
timestamp: July 20, 2011, 07:31:55 pm
content: Quote from: updatelee on July 20, 2011, 06:58:49 pmSoftrock kits have been extremely hard to get hold of... KB9yig doesn't kit them that often, although there is no reason why one could not kit their own I guess

author: gregariz
author_rank: Frequent Contributor
timestamp: July 20, 2011, 07:33:37 pm
content: Quote from: sacherjj on July 20, 2011, 07:19:42 pmI think her video's were great but I'm not really a fan of using programmable logic in this application. But that's just an engineering choice on my behalf

author: slburris
author_rank: Frequent Contributor
timestamp: July 20, 2011, 08:15:10 pm
content: I have the Open HPSDR purchased from TAPR:http://openhpsdr.org/http://tapr.org/Scott

author: gregariz
author_rank: Frequent Contributor
timestamp: July 20, 2011, 08:21:17 pm
content: Quote from: slburris on July 20, 2011, 08:15:10 pmTAPR have always been Awesome. There's some beautiful SDR stuff out there.

author: nzo
author_rank: Regular Contributor
timestamp: July 21, 2011, 05:18:37 am
content: I'm currently building a SoftRock Ensemble RX II kitset sold by Tony Parks @http://www.kb9yig.comReally good price, shipping included and gives you a choice of LF or HF bands using the same SDR board. HF bands cover 160, 80, 40, 20, 15 and 10m.There are more tutorials and info than you can shake a stick at here:http://www.wb5rvz.com/sdr/ensemble_rx_ii/index.htm(this is for the Ensemble RX II)http://sdrbuzz.com/forum/(this is a forum covering various SDR brands)I've been working with a stereo microscope and a Hakko 888 soldering workstation. Static (ESR) safety is a must. The two smallest Hakko chisel tips are great for SMT at around 360ºC using 0.5mm resin-core solder. Good quality solder and de-soldering braid is a must, as is a flux pen.Some like solder, some like lead-free. Your choice.There are some SDRs that are pre-built and come with an internal sound card as well as the SDR board. A good fast PC with USB2 and a good quality internal or external sound card are a must. Stay away from Creative soundcards. A variety of PC software SDR interfaces are available.If you want to check out SDR hubs on the net, go here:http://www.websdr.org/One of my favorite SDR hubs is here:http://wb4mak.com/-- you need java and javascript enabled on your PC to listen to these.HTH

author: gregariz
author_rank: Frequent Contributor
timestamp: July 25, 2011, 01:11:19 am
content: Quote from: sacherjj on July 20, 2011, 05:29:49 pmJust looked at my DDS-60... will reliably tune through to 80MHz

author: sacherjj
author_rank: Frequent Contributor
timestamp: July 26, 2011, 01:58:35 pm
content: Quote from: gregariz on July 25, 2011, 01:11:19 amI received the kit yesterday and built it up. About as easy of a surface mount kit as you can get. The only difficult part is the tightly spaced 7851 DDS chip (I think it is a 0.5mm). This is the first kit I did with soldering iron, rather than solder paste and hot air iron. I went back and fluxed and reflowed a few hot air. It is so much easier to let the parts center themselves.I didn't add power to it yet. Want to double check everything first.