Burt Lang wrote: > Hi Larry > > Remember me from the packet days of NEDA. > > You are confusing E F Johnson with Johanson Corp. E F Johnson do not > make piston trimmers. of that type. The capacitors used in the Sinclair > VHF Q-Circuit (BpBr) cans are 5602 Johanson caps. The key is the very > high Q of these caps. The Q of the cap controls the maximum depth of > the notch. > > Burt VE2BMQ>>> > > Larry Rappaport wrote: >> tomnevue wrote: >>> >>> I bought a Sinclair Q202G 4 can VHF duplexer. The previous owner >>> clearly spent a lot of time playing with the variable capacitors. 2 are >>> totally ruined and I suspect the other 2 are damaged because I can't >>> get a notch depth below 60db and it's not stable. These are porcelain >>> (white glass) piston style marked MAV05A30. Can anyone help me with >>> some replacements or source of supply? Any help is appreciated. Tom >>> W2MN >> >> Maybe I can help. They were made by E. F. Johnson (don't know if they >> still make them), and I still might have a couple of them. The >> problem is I might have trouble finding them as I bought about a dozen >> some 15 years ago, but I'll look. They were ridiculously expensive, >> about US$18-20 each as I recall as they are porcelain and gold. Shoot >> me an email off-list. If I have any, you can have them.
Hi Burt, Sure I remember you! And yes, you are right, it was Johanson Corp! Yes, I remember that Q is very important - that is why they are gold-plated ceramic piston trimmers. Well, we never heard back from the guy, so I guess it doesn't matter. 73 -- Larry W1HJF rapp at lmr dot com
