Suggestions wanted and a virtual show an tell

[Harry Johnson_]

OK, I've attached a couple of pics squished down into the smallest file size I could do. :)

The top one is a variable inductor that I got from Mert during his downsizing period. 

   It has an issue apparently with the wheel that contacts the coil wires - the values jump around.  I tried cleaning the wires and the wheel as best I could - paper towels, and (I think) a bit of sandpaper, but no help. If anybody has any mystical cleaner, I'd be grateful. 

Otherwise the wheel seems to be on a 5/32" shaft, it's 7/64" wide, and a 1/2" in diameter. I measured with my Harbor Freight caliper, but I think that they're close.  Just wondering if a new wheel could make the difference. 

Next is my antenna switch project from heck. Finally done and in operation thanks to profanity and some help from Steve U who put connectors on the cable for me. 

Last, but possibly the most interesting is my zigzag 10 meter antenna sitting out on my balcony. It does function, and SWR is about 1.2 or so. 10 has been pretty dead as far as I can tell, but I have checked PSK and it's getting heard. I may have even made an FT8 QSo, but I don't remember. Note: If you have eagle eyes, you might be able to see the lever lock connector that I used between the two halves. 

73, 

Harry       KF0MAB

 

[John Haurykiewicz]

Harry, from what I can see, the inductor is made up of stranded wire, and when the wheel rolls along it, it is going to make contact with the different strands, making the value of the inductor jump around because of that.   If I am correct, that is an inherent aspect of the design and structure.  I don’t think cleaning it would eliminate that effect.

John Haurykiewicz

Sent  from my iPad

On Jun 16, 2026, at 3:21 PM, Harry Johnson_ <dumbm...@gmail.com> wrote:



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[Phil Lefever]

Roller inductors like that can sometimes have contact issues. Not sure how you were measuring it, but it is also possible that sampling of some sort of digital LCR type meter may make the inconsistencies look worse than they are. As long as the contacts are reasonably free of corrosion and detritus I bet it works fine as it.

I would avoid sanding on the contact surfaces if it appears that they were silver plated, you will go through the silver almost instantly. Even tarnished silver is a better conductor of RF than shiny clean brass. Make sure the contacts at the ends of the roller shaft are good and wipe it all down is a bit of DeOxit and that inductor will outlast any of us :)

73

Phil, KBØNES