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QRP Labs
Chelmsford, May 2006 PDF Print E-mail
Written by Hans Summers   
Monday, 06 April 2009 17:44

My talk to the Chelmsford Amateur Radio Society was attended by a very large (and somewhat daunting) audience. I was asked by George G3RJV (founder of the GQRP club) to present the talk on QRP, since he had previously been invited but was unable to make it. Despite the very large shoes I was attempting to step into, the talk appeared to be well received and appreciated!

Chelmsford Amateur Radio Society website
CARS' writeup of my talk on their website
CARS' writeup of my talk in their newsletter (50KB Adobe file)


Here I am, getting ready for my talk. I plugged my laptop into a video projector and everything worked well. I had forgotten to request a video projector, but fortunately a member of the club had one in his car.
The first thing I tried to do was mention SPRAT, quarterly journal of the GQRP club, after all, this was supposed to be a talk about QRP that George G3RJV was originally to have presented.
At that time, my most recently completed project was a very simple and small USB-powered SDR 30m receiver designed for QRSS reception. It was built into the mint tin you see here. This is the webpage associated with that project.
Here it is with the lid open. The coin in the picture is a UK 2-pence piece, by the way.

During the interval, I set up the QRSS receiver's 30m wire dipole antenna outside the meeting hall. I had pre-arranged that Mike ZL4OL and Larry WB3ANQ would transmit suitable QRSS signals that we might be able to receive. Mike was sening QRSS 'O's.
Here I am listening anxiously for any signs of life in the headphones. There's nothing like the pressure of a crowd of excited onlookers, particularly when attempting something new on a newly built radio.

Here's what we saw. Chelmsford being the home of Marconi, there was a widespread consensus in the audience that if Marconi could claim 'S' reception in Newfoundland 100 years ago, we could claim this was the 'O' from New Zealand.

Actually I don't think that the line shown across the middle of the image was the anticipated 'O' from New Zealand. If it had been that distant a signal, it ought to have been subjected to more dispersion. Additionally it was somewhat less regular than the precision formed 'O' from Mike ZL4OL. I think we were suffering from some kind of local QRM probably from nearby buildings. Nevertheless it served to at least demonstrate the kind of thing we were looking for.


I brought some homebrew to show. Here's my Polyphase receiver, BCD readout frequency counter, and an unfinished 20m Pixie2 transceiver.
A closer picture of the Pixie2, which is on a PCB board "ugly" style, with a built-in L-match ATU. As yet this project is uncompleted.
Last Updated on Sunday, 19 April 2009 08:04
 
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