Mobile antenna mounts?

[WeatherWatcher]

OK I have a mount ready to fit but don't want the antenna on all the time, suggestions for something to protect the SO239 when no antenna is fitted.
Mount is a hatchmount held on with grubscrews, taking it off on a weekly basis would be stupid . I would remove the antenna when the car is not being used which can be 3 or 4 days a week - I don't trust the local oikes on a Friday/Saturday night

[26TM931]

OK I have a mount ready to fit but don't want the antenna on all the time, suggestions for something to protect the SO239 when no antenna is fitted.
Mount is a hatchmount held on with grubscrews, taking it off on a weekly basis would be stupid . I would remove the antenna when the car is not being used which can be 3 or 4 days a week - I don't trust the local oikes on a Friday/Saturday night

HI
What I have done is:
Get a old SO 239 plug, remove the center bit to keep the screw bit,
then get a Tyre valve ( the black bit that goes in a wheel)
then pull the rubber bit through screw bit, make sure the valve cap is kept on and you have a water proof cap !

Also you do get some people asking why you have a Tyre valve on the top of the car !!

[Admiral]

A condom should work.

[2SG]

One of these?...
http://www.ebay.co.uk/itm/SIRIO-WEATHER ... Swcu5URm4N

The metal ones are actually better, but I don't see anyone in the UK flogging them.