Geoff's Challenge 2012

After the popular challenge for 2012, for year 14 of Geoff’s challenges, Geoff came up with one of his tougher challenges to date – a replica Paraset, the transceiver used during WWII by the Resistance and for other covert operations..   

 

 

Two members entered the challenge, Alan Stepney G8BLW and Colin Davis G0JII.

 

 

Alan Stepney G8BLW used an old suitcase that he found in his loft in which he had stored relays.  In this, he built a 4 Valve set consisting of a 3 Valve transceiver and a power supply running from a 12 volt battery.  

 

He used a Vibrator, a 6-0-6v, 250v transformer and an EZ91 rectifier valve to produce the high voltage needed to power the valves.  

 

Alan had deliberately used a fourth valve so that he could series/parallel the heaters and use the 12 volt battery to power them.  He made a metal front panel that he finished with a Black ‘crackle enamel’ and fitted a home-made Morse Key and slow motion drive to finish it off.  

 

Using a 7.030MHz crystal, he was able to produce a 1 watt CW signal into the antenna.  He used a set of S.G. Brown headphones to listen to the receiver.  The set worked very well and was nicely finished.

 

 

Colin Davis G0JII built his set in a small suitcase that he had to spare.  He got details of the Paraset from the Internet and made a front panel c/w some ex HRO valves and he powered the heaters to make it look realistic.  

 

Inside of the case, Colin had fitted a MFJ QRP Cub Transceiver that he had recently built. On the front panel, he fitted a slow motion drive that operated the QRP kit inside the case.  He could transmit and receive on 20 metres using CW and it worked very well.

 

 

 

Alan, G8BLW won the challenge as Geoff felt he had produced a set that was the nearest to the real thing.  He won a £50 prize, made up of £25 from the Poole Radio Society & £25 by Rob Mannion G3XFD, the Editor of Practical Wireless.

 

Geoff will be setting another challenge for the coming year and we are waiting for details of this.