Taking down the pro whip antenna after it had been up for a couple of days in the rain I noticed that the balun appeared to be full of water! After undoing the screws on the casing and prising off the "superglued" lid,sure enough it was wet inside. To be fair the maker does not claim the antenna is waterproof and it certainly isn't! I need to find a way of sealing it up. I think the only solution is to fill the casing with something waterproof. Maybe silicon sealant. For now I have emptied out the water and used the YL's hairdryer to dry it out!