Tuesday, April 22, 2014

Rebuilding a Carolina Windom 80 from Radio Works

A long time ago I bought a Radio Works Carolina Windom 80 Special from an amateur who had been using it for experimentation. I think he was using it for a write up he was doing for some radio magazine, I forget which but either way he was selling it on Ebay and I got a bit of a bargain. 

The trouble was the antenna was so long (133 feet total, 50ft and 83ft with a 22ft vertical radial) I had it wrapped round the house and all over the garden, so I never really did get it working properly. 

In the end I put it away in my shed and forgot about until I came up with the idea of making it a CW 40 by reducing the wire to 66 feet total (25’ and 41’) with the vertical radial shortened to 10ft. I figured rightly or wrongly that the “matching transformer/balun” and “Line Isolator/choke” were exactly the same for the 80 as was the 40. There was nothing to contradict that on the Radio Works website so I went ahead and reduced. 

The antenna worked reasonably well and I got some good contacts, but I never really felt that I'd got the best out of it and with various wires hanging all over the garden (I had other antennas up at the time) the XYL was none too pleased. So under orders I removed the Windom and a few other antennas and instead constructed my first cobweb as a single replacement.

The Windom got put away and I used the wire for other antenna projects, the balun and choke which remained attached got stored away in my shed. 

With the recent work on the G5RV and whether I add a 1:1 balun reminded me that I had these items somewhere in the shed, so I dug them out to take a fresh look and see if a) I could use the 1:1 balun/choke for the G5RV, or b) perhaps have another go at the “Windom” project. In the end I chose the latter since it would be a shame to waste the balun and choke while they were still attached and also I had just ordered guanella 1:1 balun kit for the G5RV.

After taking a good look there is no problem with the 4:1 balun and I can certainly remove the old remaining wire and re-solder some new, so I think it’s just a case of getting the correct wire measurements and seeing how I get on. 

My only concern is that the balun is the same for a 40 windom as it would be for the 80, (had Radio Works altered it in anyway?) But in all honesty I cannot see what would change, it should still be a 4:1 balun? 

Re-checking the website I still cannot find anything to doubt my theory,(if anything I just think it's a better constructed balun), so I'm going to go ahead and re-attach the wiring and see how it performs. 

The other major factor which will now help me is that I have my own MFJ 259b before I had to borrow my brother in laws with limited time to use it and I had little knowledge in using it. So now hopefully things should be a little easier and clearer with plenty of time to get things right.

As a further update as I have now virtually completed the rebuild. Both lengths of wires have been re-soldered to the balun, theses have been cut to an approximate length of 46' and 25', the balun to choke coax remains at 10'.

All neat and tidy ready to be tested and trimmed.

This then give me room to manoeuvre as once again too much reading on the web starts to do serious brain damage. I've seen and read there are various possibilities as to the correct lengths
From 14% from the centre, to 43'-23' or 46'-20' and the list goes on! Its all to do with finding that sweet resonant spot and I guess different lengths will favour different surrounds, I just have to find the correct one for my location. 
It should prove rather interesting!  

Well today it’s pouring with rain but being somewhat keen in getting the Windom back up in the air to do some testing I've braved the weather and hung the antenna up. It’s hanging at about 30ft in the inverted V position with the wire trimmed to 41.3’ and 25.1’ respectively; this is the best trim I could get at the time with the antenna analyser, but when its pouring with rain it’s not the most ideal conditions to try and get the best out of the antenna. 

It’s by no means perfect and I will continue with the trimming with the MFJ 259 once the weather clears up a bit, but so far I can use the auto tuner on the FT1000 MP V for all the bands so I must be doing something right!

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