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Some people have a set of skills Ijust simply won’t own. These are in the design and build of complex cicuits that do stuff that most of us say WOW!

I bumped into one of those peoplea few days ago, Kevin, M0KHZ. Kevin is heavily into SDR and more specically HPSDR – High Performance Software Defined Radio. He was also the person who showed me how to solder SMD’s and made it look so simple it gave me the confidence to ruin a few pads and components. Most of which he generously donated to me from his stockpile.

At last years Dayton convention he and a few dedicated others showed a prototype Hermes SDR that was simply breathtaking (at least the box in his shack that he showed me had me wanting one immediately). Since then he mentioned that the project team had been battling with some problem with the boards and as a result needed a lot of head scratching. This thinking time is nearly over and the fruits of his and the rest of the teams labour is at an end. With a bit of luck this years Dayton will have an update.

If you’d like to know more about Hermes and HPSDR then follow this link. I’ve no real clue as to how it all works, I can certainly follow a block diagram but the rest of it is well over my head, I’m just fascinated with the end result. It may not be your thing and if it isn’t you must agree that this type of experimentation demonstrates the unique nature of this hobby. Homebrewing for me is building an antenna from scratch or a simple kit or cable. For others its at the bleeding edge of RF technology. For others its the integration with computers or building cheap and simple sub watt transmitters that get the other side of the world. Whatever the flavour I challenge anyone to come up these levels of innovation, I can only think of astronomy!

I recently got in contact with Atsushi Yokoyama (JN1SDD) regarding his project to produce software for monitoring beacons using the HF lite sdr kit and the electrically switched BPF. He informed me that he wasn’t ready to release the code for others to use just yet as it needed a bit of a tidy up. But, he has opened up a sourceforge project to release it when its good and ready.

There is an interview conducted by Tobias (DH1TW) that gives a load more detail if you’re interested.

Now all I need is a working HF lite (Mine is no longer a happy sdr, may have been damaged when I moved the garage around) and an electrically switch BPF kit. These seem to be as rare as hens teeth!

It seems as though the idea of connecting an HF Lite to a small linux box running a custom beacon monitoring program has already been done by JN1SDD. Now that someone far cleverer than me has managed to do it I’m thinking I might be able to replicate (er I mean copy) what he has done. This was something that I fancied doing but after talking to a developer of windows applications, warning me that it ‘Isn’t going to be easy’, I had taken his advice and just kept asking / googling to see if had been done.  So there you have it.

My own personal reasons are for nothing other than it could be a fun project to build a HF lite kit and electrically switched BPF and to couple that together with a small, arm based (read cheap) computer that could be used to monitor beacons whilst using less than 60 watts of power with a laptop  or netbook and tieing up a rig that I use for HF.

Time for me to make a tidy job of wiring up the HF Lite I built last year and hope that JN1SDD is feeling generous with his secrets. Good thing is it saves me having to save up for a more expensive receiver too:-)

Having been thoroughly concerned about soldering SMD’s it’s apparaent that they aren’t all that bad!

Last night I finished the preliminary build and completed the checks on the build notes. There were a few odd voltages across some of the pins of a U6 and U8 but it seemed to fire up ok and was recognised as a USB device. I was able to change frequencies and connected up the audio. There was a reassuring hiss of the noise I’d expected but slap bang in the centre of every tuned band was an enormous band of noise. None of the band pass filters were installed so this may be a cause but after checking things again and removing the HF Lite altogether the noise was still there. Maybe it doesn’t like my machine, but I’ll check again later and if it’s still there with some filters installed. Below is the screenshot

Last night i tried out my SMD sodlering skills on a very generously donated board and few surplus components, thanks Kevin, and I’m happy to say that it wasn’t as hard as I forst thought. I managed a few without any magnification and as long as there is good light then I’m not sure that its actually that hard on the 1206 type components. A couple of the smaller ones presented a bit of a problem so i tried firstly under a 2x magnification and that seemed to do the trick and used the 4x microscope to check against Kevins soldered joints.

A few were ‘over soldered’ but the technique developed and after 20 or so attempts they weren’t looking too bad. So this evening I will start on the power supply part of the softrock