Topband: A question on L's

[Peter Dougherty]

>> >6. I am reading that a quarter wave vertical has about 31 Ohm of 
>> impedance. How
>>does it get matched to 50 Ohm coax?
>
>First, the loss in the ground system will add some R to that. You can use a
>matching network, or let your antenna tuner deal with the mismatch 
>that remains.
>Again, don't worry about it unless it's a really long run of small 
>coax, in which
>case it's a good time to pop for some big coax.

I have a question about this very thing. I'm running an inverted L 
with the vertical portion going up about 40' or so, and maybe 1000' 
of radials, mostly cut to about 66' in length each. When I put my 
MFJ-259 on the coax at the shack end of the antenna I'm seeing pretty 
close to 50 ohms over a relatively wide range -- from at least 1800 
to about 1950. I'm using #14 AWG copper clad steel wire, which is 
soldered to the center conductor of an SO-239, attached to a DX 
Engineering radial plate.

Everything I read told me I should be about 30 Ohms or so at the base 
and have a relatively small bandwidth (maybe 30 kHz or so). Not 
complaining about having a flat match or the wide bandwidth, but I 
have to wonder why I'm so out of spec with this, and if in fact I'm 
heating up the ground more than I am pumping a signal into the ether.

Any thoughts on this? I'm running legal-limit power and I seem to be 
getting out "OK" but not great. I'm behind a 500' high hill to Europe 
(which is off the weak end of my L also), so I'm not expecting 
miracles out of it but it does seem to work. Should I just "go with 
the flow" or should I be looking to tweak this a little more?




Cheers,

Peter,
W2IRT