On Tue, 8 Jul 2008 16:16:50 -0700 (PDT), Jim Murray wrote:
>Don't quite understand that.
You're only giving us resistance readings, not reactance. That makes
it tough to guess what's going on. The MFJ 259 gives both R and X.
A inverted L like yours would have a resistance of 20-30 ohms at
resonance with a perfect ground. Add some ground resistance to it
and it will get close to 50 ohms. This is AT THE ANTENNA. This would
give you a 1:1 SWR. As you add more radials, the ground resistance
will drop, and the SWR will rise.
Your antenna will work and you will have some fun with it as is. Add
some radials and you'll pick up another dB or two.
One potential piece of funny biz is that your feedline may be acting
like a radial affecting the antenna. You don't want that, so I would
put a coax choke on it fairly close to the antenna.
Don't lose a lot of sleep about SWR with this antenna as long as its
below 3:1, because loss in coax is quite low at 1.8 MHz, and because
you're not running enough power to worry about breaking the coax.
73,
Jim K9YC
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