Antenna towers: don't forget drainage!

Back in 2013, I found a cheap retractable lattice tower for my 12m LFA beam.  The drawback was I had to travel eight hours to very nearly Land's End, and then eight hours back again!

Installation of the tower was, as tends to be the case, slightly hurried.  Concrete comes on the hour it is ordered, and nobody will stop it setting if you're not ready!

So it was here, cutting the last bits of metal to prepare the mount above the hole at 10pm before the 8am concrete delivery the following morning.

Base concrete pouring, back in summer 2013.

Whilst I managed to get the concrete to flood the point where it met the bottom of the metal base, it's never easy to make sure that voids haven't formed, especially with today's accelerated-setting concrete.

So, if you are going to install a tower, make sure you think of drainage.  There was a small void, maybe about 200ml in volume, beneath my tower base, which wasn't able to drain away properly.  I think it formed because the two bolts that keep the winch section in place are quite close together, so they prevented proper concrete levelling underneath the base.

Drainage channel.  No more water accumulation.

After a lot of careful cutting with a pointing chisel to make a deep channel, I then broke through a small 'dam' that was preventing most of the water from getting out.  Iron-stained bacterial mats revealed this water had been in place for some time.

Now, when water seeps beneath the tower base, it instantly drains out again.