Main mast…
A very fiddly build largely because the instruction photos are so small. I don’t know why they could not make a page turner of instructions instead of a poster format. The pictures could be so much larger; so patience is required in interpreting them.
The radar lantern at the top was an opportunity to test a brass rolling technique that I had learnt about. It may be helpful if I run through it briefly for those not familiar with it. 
- Take two sticks (or wide brass rod of the same dimension) and a surface with a bit of give. I used a sanding block that has a bit of give in it, made of a sort of spongy material.
Place the piece of brass, already annealed, to be rolled, under one of the sticks and roll until it has a marked curve.
- Place the curved brass between the two sticks as shown
Roll the two sticks away from you and very soon you will start to see that the piece starts to become circular.
And finally…
Find a stick just a bit smaller than the diameter you want and close the gap and glue or solder.