Antenna Maintenance – Hexbeam22nd November 2021
Sunday the 21st saw club members arrive at the club facilities to perform some maintenance on our G3TXQ hex beam antenna. Whilst working on our 40m sky-loop on a previous maintenance day the clips that hold the elements in place on the spreaders had slid down as we lowered the mast to relocate one of the sky-loop sides.
Arriving at the shack, you can see the state of our Hexbeam antenna. It was a super cold morning but club members Damian (2E0TXE), Adrian (M0PAI), Greg (M0TXX), Ray (M1REK), Robin (M7AQX), Arthur (M0GWF) and Chris (M0VWT) all turned up to complete the days mission.
Adrian assembling the scaffolding tower, with our mast lowered it was at the perfect height to release the Hexbeam stub from the rotator and lower it to the ground.
Once on the ground due to our location the antenna was covered in a green algae from the nearby trees. After giving the mast and spreaders a wash over we got to work inspecting the Coax, spreaders, wire elements and clamps. Thankfully all components were still in brilliant condition and it was just the element cleats that had worked loose and slid down the spreader poles.
Our Hexbeam centre support showed no signs of any issues, the previously waterproof coax connection was dry and free from any corrosion. U-clamps were still tight along with the small nuts holding the elements to the main distribution pole.
Element cleats were re-spaced according to the G3TXQ Hexbeam documentation. Some required a spot of electric tape around the spreader to get the clamp to grip. The worse being the 20m and 17m elements which had moved the most.
Greg and Adrian here are realigning some of the cleats on the spreaders and then adding cable tie as an extra measure to stop any future movement.
By adding a cable tie in front of each cleat we hoped to stop any future movement. Once this was done we quickly put the antenna on the analyser to make sure all was well. With being low to the ground SWR was higher than expected. Looking at the elements construction there doesn’t seem to be an easy way to re-tune them. This was also confirmed in the documentation. We might need to revisit this at a future date as show in the plots at the end of this post.
With all maintenance completed as best as we could and with fingers getting frozen as the day didn’t really get much warmer our Hexbeam was lifted back onto the tower and into the rotator.
Adrian here atop the scaffolding tower is resealing the coax connection with fresh amalgamating tape to keep the weather out.
SWR plots will be posted next time I’m down at the shack!