Sunday, December 15, 2013

Big Wheel Antenna

Now Bolton is not the most festive place to shop at Christmas, but this year Bolton Council have pulled out all the stops. Reindeers, ice skating and now the BIG WHEEL!

Yesterday was very impessive with the lights and atmosphere, much better that previous years.
As I stood looking at this enormous structure it struck me that this would make a superb antenna for HF.

Imagine tuning up one of these!

Friday, December 13, 2013

Kevin Davis

Kevin Davis and myself at school a couple of weeks ago.

I'm not really a football fanatic, but I respect Kevin Davis for the hard work that he did as captain of Bolton Wanderers. A great player and captain!
Now Kevin is at Preston North End. It is a shame Bolton didn't offer him a training or managerial job and kept links with Bolton Wanderers. A great guy!

Wednesday, December 11, 2013

Acorn Archimedes 3020

Photo of me with the latest computer at school in 1994
This was a strange time...the old Acorn BBC Computer was now not fit for purpose and replaced with the Acorn Archimedes series of computers. First came a the A3000 then various upgrades. They were amazing machines at the time and had in built digital storage...not a hard drive in sight! Programmes like 'My World' with the high reolution graphics and mouse controlled released schools into the the high tech world of Graphic User Interface (GUI) Amazing!
The Archimedes had a wasn't ready yet, so they brought out a later machine that looked like a PC but didn't work well.
At that stage I took a very bold decision in school to phase out the Archimedes machines and bring in the PCs. That was probably the best decision ever, even though others frowned at what I was doing. I took the school into the 21st century and had a networked PC system before most other schools in Bolton dared to venture. 
Specs for the Archimedes 3020
NAME Archimedes A3020
ORIGIN United Kingdom
YEAR 1992
KEYBOARD Full-stroke PC-102 style
CPU ARM 250 32 bit RISC
CO-PROCESSOR MEMC (memory), VIDC (Video and Sound), IOC (I/O)
RAM 2 MB (up to 4Mb possible with socketed zip ram chips)
Video ModesText Modes: 132 chars. x 32 lines maximum; Graphic Modes: 21 screen modes, including: 640×480 (256 colours), 640 x 512 (256 colours), 800×600 (16 colours), 896×352 (256 colours), 1280×960 (monochrome)
SOUND 8 voices
I/O PORTS Centronics, RS423, VGA, Network, 1 expansion slot
PRICE £749 with floppy, £899 with a 60Mb hard disk.

Saturday, December 07, 2013

SDR - Software Defined Radio

Last week I read an article in this months RADCOM by G0CHO about using a DVB-T stick as SDR to recieve all modes from VHF to Microwaves. I was fascinated by the article and also the free software to use with the stick. I have an old stick, but the chip is not suitable for SDR.
I decided to buy a new DVB-T RTL stick, so set about trying to find one on ebay. I was amazed to find a company called 'Cosycave' selling a new and fully tested DVB-T stick complete with leads and all the software required to receive SDR...and the cost?  £13.95!!!

I sent for the package and it arrived from Jersey the next day...too good to be true?

Definately not! The instructions that came with it on the disc is worth gold, very thorough, step by step instuctions on using the software and setting up the stick. Also includes SDR Sharp, an excellent and easy to use piece of software. After going through the initial set up the DVB-T stick worked straight away with SDR Sharp. I was amazed to be able to tune any frequency in all modes with just a tiny stick. Where are the tuned circuits, coils, variable capacitors? How could something so tiny receive everything from broadcast FM stations to Packet, Weather Satellites and Amateur Bands including 70cms and 23cms?

When I first got the stick receiving I listened to a local station on 2m and watched the spectrum waterfall for other stations. It seemed a bit insensitive, but then I realised that there is an RF gain control in SDR Sharp. When I found it I wound up the RF Gain and almost fell off my!
Now I am hooked on this SDR stuff, it has opened up a new dimension that I didn't know about. I thought SDR was expensive and even plug in sticks like the FunCube were not cheap. To think that you can buy the whole SDR set up for 13 quid is fantastic!

Now I am experimenting with weather satellites, with the pack you get software for decoding and displaying the weather pictures from the NOAA satellites. Today I built a 137Mhz Turnstyle Antenna which seems to work well.