Hello
I have a EF Johnson KW matchbox.
I modified it for use on 160M from ER142. 4 ea 50pf doorknobs @ 15kv across the main coil and there I am on 160M.
Lately the old girl has gotten shakey putting allowed AM carrier to the box. Tuning, with the probably destroyed (made in Ukraine) Rig Expert antenna analyzer ZOOM.........shows me an excellent match. Tuner working fine all winter. Many QSO's. Now SWR suddenly jumps up. Put that system back on the analyzer and a little working of the tuning knobs and I can get to a perfect match again.
Sprayed DeOxit on the slider contacts on the (stator??) the sliding GROUND and a little TLC on those contacts helped somewhat, but no guarantee if it will hold the adjustment and decide to drift off-resonance.
Nothing is loose or flakey. Capacitors are bread slicers that are probably almost as old as I am(
?) Nothing arced out or arcing when the tuner decides to work. Can't depend on her no more.
My HB tuner from K1JJ fame is still working and solid. So, it's not my antenna system crappin on me. It just seems that the EF Johnson gets a little more juice to the ether than Tom's design.
"Seems" like better signal reports since using the Johnson.
Any ideas?
Thanks
Fred........................I might decide to build this monster tuner down the road and have a tuner shootout using a field strength meter and the camera on my cell to see any increase / decrease