Unfortunately, I've recently had a lot of experience with Cushcraft traps.
To get them apart, remove the end caps, place the inboard end on a vice
with the jaws just catching the case (not the insulator), and use a
block of wood and a hammer to drive the innards out. Carefully.
The difference in TB and TC is a small difference in resonant frequency.
TB may have one fewer turn, or it may just be tuned higher with the case
position and/or number of outboard insulators. I don't know about TD and
TE, but the higher resonant frequency probably goes in a director.
The best way to identify the traps and determine if they're working is
to measure the resonant frequencies. (I can find the data, if you want
it.) I found it almost impossible to couple a dip meter to the trap.
However, I was able to measure the resonance by placing a probe on
either side of the outboard end, extending just beyond the end of the
case, so they were loosely capacitvely coupled to the center tube. One
probe came from a signal generator (just a clip lead coax), the other
was a 10X scope probe. At resonance, I could see a sharp peak on the scope.
The original Cushcraft traps are built much better than the new MFJ
ones. If you're using the MFJ ones, I can suggest some modifications.
Hope that helps. Contact me offline for more info.
73,
Scott K9MA
On 11/13/2019 13:02, Tom Wylie wrote:
Anybody got good advice re the opening up of traps for an A4S without
destroying them. What physical difference is there between TB and TC.
And TD and TE? The markings are worn off the traps
Tom
GM4FDM
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Scott K9MA
k9ma@sdellington.us
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