Sunday, 20 March 2016

CTARC Why Attend A Work Party? - 20 Mar '16

There are some obvious answers to the above question, and some hidden gems.

Clearly, the first reason we should pitch up is that there is a job to be done. Yesterday, ten CTARC members arrived to sort out the rotatable beam antenna at the CTARC clubhouse, which has been giving intermittent and faulty readings. The antenna needed to be repaired.

Another (sometimes less obvious) reason is that the job requires several hands. So, we couldn't safely lower or raise that antenna without at least four (and preferably six) people to operate the winch, hold the stays and check for true in the process.

Yet another reason is the job requires expertise. Without the presence of Rob / ZS1SA, Danny / ZS1BL and Richard / ZS1RIC, that mast wouldn't have been lowered, We were also fortunate to have Fred / ZS1FZ at hand. More on this later

Then there are the less apparent, but no less tangible rewards of fellowship - working together cooperatively on a common cause can be very satisfying, and you certainly get to know your co-workers as the job proceeds. You also learn something about yourself!

But here's the crux. Yesterday I learned something new while watching Fred / ZS1FZ at work.This gentleman really knows his stuff, and it was both a privilege and an education to watch him at work.

I learned that you don't solder coaxial cable's copper conductors to lugs that will attach to a beam antenna's feed points. Doing so creates a brittle joint that will eventually crack. Also, soldering dissimilar metals together in that location creates an electrolytic reaction that will eventually corrode the joint.

What you rather do is to crimp the joints - with a proper crimping tool and a correctly sized lug, so that the co-ax's conductor and braid are tightly held in airtight grips that provide good conductivity and yet a little flexibility. Those connectors can then be protected with self-sealing tape or Denzo tape. (Think all this is still nonsense? The aircraft manufacturing industry uses this crimping technique on the thousands of electrical connections in any modern aircraft).

I also learned about self-vulcanising tape - a fancy (and expensive) product that stretches as you pull it and eventually amalgamates around the protected joint or piece of cable. And about using this tape to protect exposed parts of the feed line cable that might become brittle or corrode when exposed to wind and UV for years. And about some fancy waterproof UHF connectors that (again) don't require soldering the braid - just the centre pin.

I also watched how Fred checked the antenna and cable SWR with his MFJ antenna analyser, and how his background knowledge about what the readings should be in context caused him to go back and check and re-check, until all the faults were eventually identified.

So that's why attending your club's call to arms for work parties is such a good idea - you really do learn so much!

And there's another reason. Our club's guru's - who are our elders and very much our betters - have huge knowledge to share. Sadly, because they are our elders, at some point we will lose them and their knowledge (very long may that day be in coming). So we had better learn what we can from them, and  acknowledge their great contributions, while yet we can.


Nick / ZS1ZD