[MAMS] 1296 looper

[Lloyd Ellsworth]

Had my first failure of a loop antenna, in, well, ever since I started using them. When G3JVL came up with them in the RSGB Journal. 1970 whatever. Still have the first ones I built. 


Been having trouble with the rover 1296 looper for some time. Top antenna on Rover. Because it is up on top, it meets up all the time, with branches, foliage and all. Fixing it all the time. Started getting intermittent results. I usually attributed it to poor band conditions or location, and moved on. Sometimes it worked fine. Sometimes not. Started keeping a watt meter in line, looking for any problems. Kept watching it. Last few contests, started to note some SWR issues. Especially with the 75W amp. 


Finally found the problem today. Going over the antenna. Straightening bent loops. Looking at the driven element, noted a slight micro crack, discoloration, just above the boom ground connection of the UT.141 matching section. Wiggle, bright light and the magnifying glass and could see the crack. Playing with the IC8 HT, SWR and 1W Bird slug. Found it. Crack went all the way around. Just at the edge of the solder. Right weather, temperatures, making that intermittent connection, intermittent. At other times, not. Intermittent connections and problems, are always the most "fun". Well, then spent some time to find parts, and replace it. Now to test it. By using it. 


Hate to even suggest how many hours disappeared into this intermittent problem. How many lost contacts. Already wiggled it so the PTFE dialectric now clearly shows. If I get ambitious, will throw it in the example box of problems found. Another grand show and tell item. 


Yes, I have known about making loops, curves, for allowance for expansion in the lengths of semi rigid. Been doing that since day one with it. Well, first time with a loop antenna. Kind of hard to do, with the loop feed. This is why it takes me most of a day to set up rover for contests, etc. Then events like MAD to try things out. I do not presume every cable, antenna, connection, connector is good. I test them all. Amazing what you find that does not work. Test everything. 


73, Lloyd NE8I/r
EN74 etc

ne8i at arrl.net