Deunan
With a piece of wire 
23rd-Jun-2012 02:56 am
SDR in 5 easy steps:

1) Design your radio

2012-06-23 DR2A PCB

2) Build it

2012-06-23 DR2A working

3) Get control software

2012-06-23 HDSDR @ 7880kHz

4) Get decoder software

2012-06-23 MULTIPSK HF FAX

5) Amaze your friends

2012-06-23 Weather Fax 7880kHz


Considering I got this far with a 2m piece of wire hanged across my window, I'd say it's a success :)
Comments 
23rd-Jun-2012 03:00 am (UTC) - Cost
Anonymous
How much did the board and building end up costing you?
And the time to set it up?
23rd-Jun-2012 07:48 am (UTC) - Re: Cost
Hmm... About 100$, maybe a bit more. I had to order those PCBs at prototyping service, and then buy most of the components online. I wanted SMD to keep the board small and have most of the bottom layer as GND for shielding. Soldering SMD electrolytic caps is a nightmare :)

So, THT is going to be cheaper, especially if you can do the PCB yourself. Even single-layer one is good enough with a few jumpers here and there. Connectors are optional, wires can be soldered directly.

You still need a signal generator at 4 times the frequency, about 1Vpp, to drive the quadrature demodulator used here. I used AD9850 module which I bought cheaply + MMIC driver. I'm setting it up via USB with FT245 module I already had. I can make a picture of that as well if you're interested.
24th-Jul-2012 09:59 pm (UTC)
Anonymous
just a lil quationj,
did you left the progress on makaron at all?
25th-Jul-2012 01:06 pm (UTC)
No, I'm still working on Makaron but I'm busy with many things.
27th-Jul-2012 10:31 pm (UTC) - Schematics?
Could you provide schematics and names of software used for that SDR?
If not, could you at least name your references and methods used?
Thanks.
28th-Jul-2012 08:29 pm (UTC) - Re: Schematics?
Everything is here: http://yu1lm.qrpradio.com/sdr%20rx%20yu1lm.htm
Be careful though, there are some mistakes and omissions in the schematics, you should read all the PDFs there because the later ones contain updated and corrections.

Some of those errors are easy to spot but there are also changes to resistor values.

Note that this SDR is not based on Tayloe mixer/detector, rather is two balanced sample and hold detectors that make up a complete quadrature demodulator. I like this approach better and it has some neat features like less problems with 2nd harmonic (and 3rd is considerably less powerful) and better sensivity.
This page was loaded Jul 24th 2014, 2:45 pm GMT.