Geoff's Challenge 2009

For year 11 of Geoff’s challenges, Geoff came up with two challenges that complemented each other.

Challenge 1 – A Receiver that could receive the International Space Station

For the first challenge Geoff was looking for something to produce enough power for a radio without using batteries.  Geoff had in mind something that generates the electricity from mechanical means.

Challenge 2 – An antenna to receive the International Space Station

For this challenge Geoff was looking for something that could be used in the field where a suitable operating position was not available.

Entries

A Receiver that could receive the International Space Station

There was just one entry for the first Challenge.  Phil Ciotti G3XBZ, submitted a regenerative receiver (see picture on right) that could receive signals in the 2m band.  It was based on the CQ2 receiver published in the November 2004 issue of Practical Wireless.

 

An antenna to receive the International Space Station

For the second challenge, there were 4 entries.  

 

Phil Ciotti G3XBZ, produced a 2m Slim-Jim antenna using ribbon feeder and a cocktail stick to separate the ends.  

 

Alan Bowers G8FWF, produced 2 separate antennas, both made from left-overs from recent plumbing jobs at home.  The first of Alan’s entries was a 2m turnstile antenna (see picture on left) using stainless steel bicycle spokes as the elements screwed into a plastic pipe.  A ¼ wavelength of coax was used to match. 

 

Alan’s second antenna was a J-Pole made from copper pipe left over from his shower installation (see picture on right).  Alan reported that he had used the antenna on the club net recently, and that it had a SWR of 1.4:1.  Most importantly, Alan said that he had heared the International Space Station with it. 

 

The final entry from Eddy was another turnstile, this time à la Moxon.  This one is based on half-wave loops, and reception of the local 2m repeater was demonstrated using it.  Eddy’s entry was made of 10mm copper pipe with wooden insulators  

 

Members voted Eddy’s turnstile the winner, with Alan’s two antennas equal second.

 

Eddy is seen on the left holding his winning antenna.

 

 

 

 

 

Don’t forget Geoff’s Challenge for 2010