WB4IUY's Random Blog

I've been in Amateur Radio since 1974, and still find new and interesting things to do. I like to build, restore, and operate on the air. This is a blog of various info about my Ham Radio operations and activities, projects, and opinions. Visit www.WB4IUY.net for the lowdown at WB4IUY.

Thursday, May 10, 2018

Rebuilding a Cushcraft A3S HF Yagi...

This is one of the Cushcraft A3 Antennas I had, this one was on the tower when it came down in the storm on April of 2016. It was bent up and broken pretty bad, but considering they're selling new for $600 + freight these days, it's certainly worth rebuilding. I started by sorting through the wreckage, and trying to figure out what parts went where...


It was pretty bent up and broken, but I was able to kinda sort it all out. Some parts were removed from the trees, some parts were still attached to the mast, and some parts were broken off and scattered across the back yard. I located the boom, removed all of the brackets and such, and put it to the side...


Next, I gathered up the various bits and grouped them together by element... reflector, driven element, and director parts. I bundled it all up in groups, and stored it away for later. After all, I had another HF yagi to put on the tower and bigger fish to fry first, but planned to come back to this and rebuild it later. 



Well, 2 years passed, and I've rebuilt all of the other antennas for the tower. I have installed a Force 12 6 element HF yagi, and the others I recently rebuilt are ready to go back up. Now the time has come to get this beast rebuilt and find a new home for it. I restarted this rebuild by first cutting out the bad and broken sections, and straightened the other parts (elements and boom sections). I will order some aluminum tubing to splice or replace the damaged sections where necessary (not that many places, surprisingly!). 

I decided to disassemble every trap, clean them out, check the internal connections, and replace all of the plastic end caps on them. The real chore was to sort the traps and label them, since there are no permanent markings on them... the TB & TC traps all look the same. I found a chart on the web that told the approximate resonant frequency of each trap, built a simple coupler for my MFJ antenna analyzer to use it as a dip meter, and checked each trap. They're now tested, tagged, and waiting for new end caps...





That's it for this blog, I'm waiting on some aluminum tubing, new stainless steel hardware, and replacement end caps for the traps / elements / boom. I'll probably build a new and stronger center insulator for the driven element, next...

Dave WB4IUY
http://www.WB4IUY.net