The YBB boom tether system

Like many hams, when there is a lot of wind about outside I have to check on how the mast is doing. One thing I did not like was the way the wind rocks the beam back and forth on the rotator. I figured this cannot be good long term of the gears, especially as they seem to be mostly plastic. (Unverified)
When you have something like a 20m moxon up the play back and forth looks quite dramatic. So here I am sharing my YBB boom tether system idea.

For a couple of years now I have had a small arm attached to the stub mast and I guyed that down but it was very short and even with a lot of tension the boom still moved about in bigger winds. Also was quite a lot of  sideways downforce on the rotator (I don’t have a cage).

So in the design and build of my new 20/15/10m tri-band 2 ele beam I incorporated a tethering system on the boom itself at each end to have more effect and balance the side loading to the rotator.

This has proven to be very successful, keeping the boom practically motionless while the 20m moxon element dances all over the place. So I thought I would share it as an idea for others, especially those with a christmas tree stack of beams. I always retract the mast when not on the air, but I know others also retract their masts when high winds are due, and this could help then.

This is the mast retracted to about gutter level and the beam tethered. The left hand tether point is close to the 20m driven because the balance point of the beam is to the left of the 10m driven so it was a small contribution to try and reduce the imbalance on the mounting point.

triband beam tethered

The tether points are very simple. Some aluminium angle, a square U bolt and a round U bolt. These MUST be stainless. (Trust me I know!)
tether point detailTo hook the rope on these I use a plated steel (must NOT be stainless) clip from screwfix. I then file the head off the gate pin to remove that.
Smith & Locke Karabiner 10 Pack

Then this is what they look like installed:
tether fitted detail

Once fitted they are just tensioned up with sliders as I use on all my guy ropes:
tether rope sliders
Now I know by now you are wondering how on earth I get them on and off?
Well that is quite simple and surprisingly easy. I use a telescopic fishing pole with some neodymium magnets taped to it to both fit them and remove them for winding the mast up:
tether fitting pole
All dead simple stuff but it is really effective.