Ignition Screening - Gipsy Major

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djwood
Posts: 12
Joined: Fri Apr 23, 2010 7:44 am
Location: Old Sarum

Ignition Screening - Gipsy Major

Post by djwood » Tue Apr 23, 2019 10:08 am

I have a Gipsy Major which does not have screened ignition. Using my old 25MHz radio the background ignition 'noise' was fairly low-level and quite manageable. With the new 8.33 radio it is much more noticeable. It's not a problem on the intercom or when close to a ground station but when I am trying to receive transmissions that are weak it can make life a little difficult.

I have standard 14mm car-type spark plugs. What are the options for replacing my unscreened ignition with screened ignition?
David Wood
FI(A)/FE(A) based in the South West
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tnowak
Posts: 431
Joined: Wed Jan 02, 2008 12:00 pm

Re: Ignition Screening - Gipsy Major

Post by tnowak » Wed Apr 24, 2019 7:26 am

Give Graham Keele at Hants Light Plane Services a ring: 01264-860056.
He is at Chilbolton and has recently assisted someone with using screened plugs on an Auster engine.
Tony
Tony Nowak
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john.henderson1263
Posts: 7
Joined: Fri Aug 10, 2012 9:39 am

Re: Ignition Screening - Gipsy Major

Post by john.henderson1263 » Tue Apr 30, 2019 9:57 am

We use unscreeened plugs on our Gipsy Major and the newTrig radios reacted badly! We simply applied mesh sleeving externally from the plug base to the metal conduit pipe that carries the HT cables to the magneto. the mesh is earthed using a flex metal earthing strip running from a screw on the magneto case to each of the four mesh strips and connected using jubilee clips. The mesh is held in place by discrete cable ties, which we replace each time we service or change the plugs. It works.
John Henderson
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djwood
Posts: 12
Joined: Fri Apr 23, 2010 7:44 am
Location: Old Sarum

Re: Ignition Screening - Gipsy Major

Post by djwood » Thu Aug 29, 2019 9:01 am

Thanks John. And do you use screened plug caps of any kind?
David Wood
FI(A)/FE(A) based in the South West
019588

john.henderson1263
Posts: 7
Joined: Fri Aug 10, 2012 9:39 am

Re: Ignition Screening - Gipsy Major

Post by john.henderson1263 » Fri Sep 20, 2019 3:41 pm

sorry for delay in reply, been on holiday. No we don't use screened caps. we carry the mesh over the HT connector at the top of the plug, all the way to the plug base and cable tie it there. we obviously replace the ties each time we service the plugs.
John Henderson
035727

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