Friday, 28 November 2008

Software Defined Radio - Softrock V8.3

My new interest is SDR and I decided to build a Softrock (HF band) receiver kit. This little radio is the bees knees as far as I've read. I will let you know more later. The main board and one of four filter boards was built after 17 hours. Each stage was tested as I went along during lunch breaks at work. The stuff had to be set up each time hence the long total build time. Here is a picture of my Softrock V8.3 with the 15m/12m/10m board plugged in.
The build instructions are the best I've ever seen for any electronics kit. Instructions here. There are even video links for smt component soldering and inductor/transformer winding techniques.
I have downloaded the latest version of Rocky software that runs the radio and will be trying it in due course. Luckily the Audigy soundcard in my PC is a separate soundcard board that is dedicated to HAM and I'm hoping it will be adequate for the job in hand. I hope to sync. my ICOM 746 via the software HRD Deluxe so that both radios will tune in tandem.
Now completed the hardware (33 hours build time) and have thoroughly enjoyed the build. The software installation has started and I have already picked up ssb and cw on 160m.

I have now added audio isolation transformers (removed shortly after trials) on the audio outputs, salvaged from old PC modems, and built an IC2 AVR controller card. I managed to squeeze both units into the box. The AVR card links to the USB port on my PC and makes the band selector dip switches redundant, however, I now have full hf band capability. Winrad is my favourite SDR at the moment and band selection is transparent i.e. I don't select the dip switches anymore, with this software. What I do have to do is change the front end filter (1 of 4). I switch the ocf antenna between this radio and my ICOM IC-746 with an antenna selector switch. When comparing the sound on my headphones when both radio are tuned to the same frequency I am very impressed with the SDR, the quality is really excellent. I have wired a dedicated input for the SDR to an Aux input on the soundcard board inside the PC for best results.
6-1-2011.  I also use HRD 5.0 logbook at the same time as HDSDR radio with port sharing software by Eterlogic.  The radios sync with OmniRig.
6-10-11.  Disconnected earth of IQ output, that goes to Notebook, to stop earth loop hum.  SDR gets earth via the USB connection in my case.  Now 100% better as I seemed to get a lot of break through before.  It used to sound like the radio was running before you even started the software.  That noise has been completely eliminated.

Calibrate Softrock Procedure.