Hi Folks,
Now that it's warm enough outside (103 degrees) I thought I'd spend the
afternoon on the concrete
driveway and fool around with matching the input to the BB3 mobile
antenna. Found some scape
2.5 inch airdux, cut off a 14 turn hunk. Connected one end of the coil
to the antenna input and the other to ground. Tapped the coil with the
center conductor from the coax...couldn't get a good match. Moved the
ground sideup the coil with a ground jumper. Ended up with using four
turns of coil with the coax tap at the feed point of the BB3 and the
ground strap located 4 turn below. I set the antenna to resonate at
7.225mhz before I started this exercise.
The measurement/results were are follows:
Frequency R X SWR
7.185 100 21 2.0
7.210 69 0 1.3
7.232 53 0 1.0
7.251 43 10 1.2
7.265 39 18 1.6
7.281 34 25 2.0
SO, does it look about right?
HAVE FUN,
dave
WA3GIN
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