SDR ham radio - hobby or enterprise??

[AA7EJ]

After dismal propagation during FD I am turning the rig off and soldering iron back on.
Like the idea of Software Defined Radio, however, finding out that majority of initial web publicized ham SDR projects are now "for profit" enterprises. To be honest, found some home brew projects of interest. But most “site updates “ are couple of years old. There are few scattered articles here and there on various web sites.
So, is there a current SDR ham radio development going on? (Please skip references to HDSDR and SoftRock).
73 Vaclav AA7EJ

[KC4RAN]

Flex is doing the most commercial side of things, and although you said don't mention them, the HPSDR group is probably closest to the cutting edge from a group perspective. There might be individuals doing higher end research, but I haven't seen mention of it.

The Mercury board is probably what I would consider the highest end of the research. Direct sampling (no conversion, no IF stages) from 0-65MHz.

[AA7EJ]

http://f4dan.free.fr

PS Anybody in Houston with similar interest building SDR?

[wa3vjb]

I hope you are not being too rigid in drawing a boundary between "ham radio" SDR and the ongoing development you can find in the commercial arena. As Flex has shown, there's a lot of crossover.

That said, may I suggest a posting with your query over on http://amfone.net with a specific reference to Frank, WA1GFZ.

There is an active, vibrant homebrew community over there that is developing SDR receiver techniques for use with Amplitude Modulation. I'm sure you will find some kindred spirits discussing and developing from some of their work, led first and foremost by my friend Frank.

Best wishes

[AC0FP]

Flex is doing the most commercial side of things, and although you said don't mention them, the HPSDR group is probably closest to the cutting edge from a group perspective. There might be individuals doing higher end research, but I haven't seen mention of it.

The Mercury board is probably what I would consider the highest end of the research. Direct sampling (no conversion, no IF stages) from 0-65MHz.

That sounds expensive! I worked as a consultant 7 years ago on a military project that did use conversion (from 1.1 GHz), however, the baseband conversation to the DSP was 60 MHz. Those 60 MHz DSP chips were expensive.:eek:

[N2RJ]

The hardware itself is commercial, but by all means feel free to write your own software.

The point of SDR is that the software is the radio.

[KC4RAN]

That sounds expensive! I worked as a consultant 7 years ago on a military project that did use conversion (from 1.1 GHz), however, the baseband conversation to the DSP was 60 MHz. Those 60 MHz DSP chips were expensive.:eek:
Looks like the LTC2208 is around $100 in qty 1, as far as I can tell. If someone can find a better price, I'd be interested to see it.

[AA7EJ]

Thanks to all who are participating in this thread.
I started my interest in SDR few years back ( I have checked HDSDR group than) and finally getting better feel for some of the challenges of the subject.
Here are some of my opinions so far.
It is called “radios for masses”, but it is a misleading term - the necessary hardware complexity and therefore price can go from $10 up to $1000’s.
The price tag of designs based on direct conversion using quadrature detection is considerably less than the price of "bleeding edge" designs using true AD converters.
It seems that many “specifications” are really outstanding, albeit somewhat overkill.
So far I have not head anybody commenting on how SDR receiver really outperforms in ham radio daily usage. (With exception of EME experiments).
I am not sure how to put this – but most interfaces appear designed in VB and very cluttered. Personally speaking – no matter how sophisticated the software is - the interface should have simple tuning and volume control first.
It also looks like the main “selling” feature is old fashioned panadaptor. IMHO the only technical value of “wideband display” is to see lid overdriven transmitter splatter, which can be heard by using galena crystals! (Just kidding).

Anyway – here is my plan.
Build simple diode “mixer” (TinySDR http://www.qrz.lt/ly1gp/SDR/ ) with one transistor LO probably on 7 MHz.
Use available software for processing and add simple visual interface.
When this is running – replace the “front end” with modified SDR 1000 – I have the DDS oscillator already.

[k2bet]

Hi, Gang. I have just jumped into the SDR pool and find it absolutely fascinating and it is incredible what a few bucks and a few days will reward you with in terms of enjoyment.

I purchased several of the SoftRock kits from Tony Parks recently. After outfitting the bench with appropriate tools to begin my foray into surface mount technology for the first time in my 65 years I was ready to endure.

Well, that was three days ago. I am proud to say that I have completed the first kit, the SoftRock Lite 40 meter receiver in about 12-14 hours of focused soldering... and I mean focused! (In my recent communications with Tony he reports completion of no less that six of these units over the same period of time!)

There are several tests offered before hooking up the nine volts and in one of mine the result was a resistance low enough from the expected to be of concern. So I turned to email and was able to reach Tony with a response to my concerns in less than one hour. After several exchanges of email and further tests with poor results it was concluded that I was using the wrong 'test points' to get my readings. Once I did it correctly everything looked according to expected specs and I dared to hook up a nine volt battery to the PC board. (About 1.5 X 1.5 In. Square!) Nothing fried and the voltage at the output of the 5 volt regulator showed 4.98 V DC! So I like to think that this was one of those rare moments in life when one thinks he made a mistake (Assembling the kit) but was wrong about that. I had had actually assembled the kit A-OK! ie "I thought I made a mistake, but I didn't!)

I was ready to hook up an antenna and plug the little puppy into my computer's sound card. I downloaded some of the several free versions of software available on the Internet and voila! I was hearing the RTTY contestants of the weekend's 'TEST' and copying CW across nearly 40 KHz of the low end of 40 meters. I even had occasion to run across some South American DXers on SSB whose signals were demodulated perfectly using 'WinRAD' software (Thank you, Alberto di Bene, I2PHD.)

So... if I recall correctly, the cost of this kit was around $10.00 US. Tony is also producing RX/TX kits for under $30.00 which can be built to any of the band's specs and put out a milliwatt or so. I see he now offers an 'all band version' kit for under $50.00. You cannot beat these projects for ease of construction, limited expense and maximized enjoyment, if you like wielding a soldering iron and listening or transmitting on the short waves. I encourage the perusal of more info at Tony's site: http://www.softrockradio.org/SoftRock . These kits won't provide everything for daily amateur use, (Such as the FLEX 5000) unless you enjoy the elegantly primitive as I do, but they will be sure to edify and entertain you in the new technology of SDR. Go forward... and getter done!

Back to my play...

73,

Bruce, K2BET