True but I am talking about an unofficial install.
That doesn't help anyone! A
new Mode A/C transponder installation on ANY aircraft that wants to enter airspace that requires transponder carriage is against the requirements of the UK ANO. For new installations, it MUST be Mode S. You can only operate Mode A/C if it is already fitted (until 2012), or if you never enter transponder mandatory airspace. Later this year the general UK glider exemptions are likely to be revoked, meaning all aircraft will be treated the same, powered or not. There's a reason Mode C transponders are cheap on Ebay, because very few operators can fit and use them now (legally!).
Mode S is absolutely critical in the context of gliders as Mode S is the only way to track a gaggle of them in close proximity. A group of Mode A/C equipped gliders will lead to garbled replies and false targets presented to ATC.
I understand the issues related to length of flight and battery support for transponders, I sat in enough meetings with UK CAA, transponder manufacturers and flying representative groups looking at alternatives to suit the gliding and microlight fraternities (lightweight Mode S transponder) but unfortunately it hasn't got anywhere yet
This is a free forum for people to post what they want, but IMHO it would be wise to ignore advice to perform illegal installs, it defeats the whole point of the transponder regulation in the ANO.
RS