Any masts at this location are earthed, but then they also have Transmitter/receiver antennae on them.
Easiest way to do it, Buy an Earth rod off E~~~ or builders merchants I think I got mine from Wickes, Jubilee Clamp size of Mast and then run from the earth clamp to the mast Earth cable available from your local Electrical wholesalers - Must be the heavyduty cable, I use 2.5mm solid copper.Use the sleeved stuff.
The earth rod has a screw fitting on the top and the other end just tuck the wire under the Jubilee Clip and tighten.
But I also have lightning arrestors in the coaxial feed for the Radio stuff.Linked in the same way.I only have one metal mast ,the other two are Fiberglass so are insulated anyway(Old windsurfers have their uses)
Don't think there would be a problem with wireless units however It is something I would do on on a wired unit.