[TowerTalk] Telrex TB5

[n4kg@juno.com]

We had a Telrex TB6EM at the University of Michigan ARC,
W8UM, back in the 60 / 70's and noticed a similar problem.
There was almost no pattern on 10M and the SWR was high.

We re-resonated the 10M traps by adding a "gimmic" across
the trap.  A "gimmic" is a pair of parallel wires taped together
with opposite ends connected across the trap and the other 
ends unterminated.  I believe we had about 4 inches of overlap.
I don't recall the size wire.  #14 insulated copper wire should
work OK.

Check the lengths of the 10M reflector and director.  My 
guess is that they were tuned for use at 29 MHz.  You can
model a tribander as a 10M monobander fairly easily to
see where the 10M elements should be tuned.

73 / GL,  Tom  N4KG

# # # # # # # # # # # #

On Tue, 25 Jul 2000 14:30:02 -0500 dj2001@isd.net writes:
> 
> Here we go again with the Telrex.  I'm searching back thru the 
> postings but have not come up with anything yet.
> 
> Does anyone know what the values of the capacitors are in the traps 
> for the Telrex TB5EM tribander?
> 
> I think I might have some bad ones and dont want to tear into it 
> unless I'm sure I can fix it.  The antenna works but not very well 
> on 
> ten.  Twenty and 15 seem ok except on 15 the resonant freq is about 
> 21.45 and drops off slowly well down the band, its acceptable.  Ten 
> is at 29.3 and 2/1 best case.  I have rebuilt the balun and cleaned 
> everything.
> 
> Dale J.
> K9VUJ
> 
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