Hi Trevor
Read Joe, W4TV's answer again !
The coil should be whatever inductance you need to resonate your slightly
short antenna . . . then you can use that coil as an auto-transformer to get
a good match, ie once the antenna is resonant, you can feed your coax a few
turns up the coil.
But your coil sounds WAY too big to me ! And with that big a diameter, you
may need to adjust the tap a half a turn or less. So I would use a 2"
diameter, and I doubt if you need more than 10 turns.
If you don't have any suitable gear to assess this, then try this:
On a 2" diameter coil, connect your coax inner two turns up the coil from
ground. Now try tapping the end of the antenna vertical wire up and down
the coil, and find where you have the best match.
Once you are at that best point, if the VSWR isn't 1:1, try moving the coax
tap up a bit. (just one turn at a time)
Roger G3YRO
>Thanks everyone for the replies, I'm new to all this so you may go easy on
me, I
>don't understand this R+JX stuff so I need a dummies guide if possible,
>I Have the vertical section at the top of the coil and I connect the feed
line to it
>where I can get the lowest SWR at 1.825mhz,
>Does the amount of coil left under the tap matter I didn't know it would as
it's
>going to ground,
>Ideally I don't want to drop the loading wires as they are not easy to get
to but I
>can if I need to,
>Thanks
>Trevor
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