First the 'T' is just that a ' T ", not a coupler
/ combiner. [see below] The coax is usually seventy five ohm for
the television set so that is what we want to use.
The length of coax in the drawing from the ' T ' to the TV is not required.
If you can find a ' T ' with one female and too male ends you can connect
the ' T ' directly to the TV set thus eliminating the coax from the set
to the ' T '. The coax 'open ended stub' is cut for the frequency
that is causing the interference, this is the free space length times the
velocity factor of the coax used. The best coax I have seen for TV service
has a velocity factor of 0.8 some will be as low as 0.58, so use the 0.8
plus a little, say 1/2 inch install the trap and trim the stub for the
best operation.
Another option is to use something like the MFJ
259 instrument to adjust the stub the folks at MFJ have included
instructions in their manual for this operation. Remember the loose end
is open circuit!
The stub is fairly broad so if you work all of six
meters just cut for the middle of the band and it should do a reasonable
job for you.
A good starting point for six meters is 59 inches for the stub. You
will need to trim this down for the stub to work, not knowing what coax
and
' T ' you will be using I can't guess any closer for you.
