Having recently (January 2013) started a re-arrangement of the antennas at my QTH, I took the opportunity to relocate my Sirio 4m Vertical Antenna onto a taller mast.

I was surprised at the amount of corrosion that this antenna has suffered as it's only been up around 18 months. I know that my proximity to salt water doesn't help, my QTH being only about a mile from the Northern edge of Langstone Harbour.

The photos show the corrosion of the SO-239 Socket and also the telescopic top section of the antenna where it is held in place by a grub-screw. After cleaning off the corrosion and the antenna was re-assembled, the base unit was waterproofed with sealant around the bracket. In original unmodified condition, i.e. from new, rainwater runs down the antenna, across the top of the lower part of the bracket (under the thick part of the antenna) and down the SO-239 socket into the SO-259 Plug threads. The sealant (just wiped around around the base - not underneath) prevents this. I made this situation worse by using self-amalgamating tape from the plug to the rubber bush that surrounds the socket, effectively making a well for the water to collect in. This black rubber bush (which looks like a waterproof tight fit around the antenna socket, but it isn't) is now permanently removed and the plug / socket waterproofed with self-amalgamating tape in the normal way.

The joint where the top vertical section of the antenna slides into the bottom vertical section is now also covered with self-amalgamating tape to stop water ingress / corrosion. On initially dismantling the antenna, the lower hollow part of the whip was full of water !!

Please note that none of the above seemed to affect the performance. It was working very well despite the above before I took it down to re-mount it on the higher mast. Eventually though I'm sure its operation would have suffered. Hopefully it will now last and perform well for many years to come.

These antennas are great performers, but if like me you live on the South Coast, it may be worth taking a look at it from a maintenance point of view. I hope the photos assist in some small way.

73 de Mick M0GWD