Hi Folks,
I'm trying to build a mobile dual band antenna for 6 & 10 meters.
I read an article back from a year ago in QST where the author
started with a full size CB whip, cut it half, and used a polycarbonite
coupler (with a trap built on it for 10m).
Sounded ok, but I neither had a CB whip, nor did I have a way to
make the coupler.
I did have one of those helically wound HF mobile antennas for 20m
that I could sacrifice to the project.
Got the base all wound & had an excellent match on the 6m FM
frequency that I wanted (had to add about 47pF to the base to
make it happy). Then I made the trap at the top of the whip
for 10m (with the whip attached to the top).
When I checked for the 10m resonance, I found it to be a little lower
than I needed, so I decided to pull a couple of turns from the trap.
Before I did that, I re-checked the 6m resonance point, and it had gone
up to 60mHz!
Anybody have a clue what's going on here, & why it jumped up?
Thanks,
Tim W5FN
I'm trying to build a mobile dual band antenna for 6 & 10 meters.
I read an article back from a year ago in QST where the author
started with a full size CB whip, cut it half, and used a polycarbonite
coupler (with a trap built on it for 10m).
Sounded ok, but I neither had a CB whip, nor did I have a way to
make the coupler.
I did have one of those helically wound HF mobile antennas for 20m
that I could sacrifice to the project.
Got the base all wound & had an excellent match on the 6m FM
frequency that I wanted (had to add about 47pF to the base to
make it happy). Then I made the trap at the top of the whip
for 10m (with the whip attached to the top).
When I checked for the 10m resonance, I found it to be a little lower
than I needed, so I decided to pull a couple of turns from the trap.
Before I did that, I re-checked the 6m resonance point, and it had gone
up to 60mHz!
Anybody have a clue what's going on here, & why it jumped up?
Thanks,
Tim W5FN