There are an infinite number of solutions.
The most popular are to tune the length for resonance
where the is ZERO reactance and then match the
(low) real impedance to 50 ohms, OR, to adjust the
length to provide 50 Ohms plus some inductance and
use a single capacitor to cancel out the inductive reactance.
Tom N4KG
On Sat, 10 Aug 2002 20:17:23 -0000 "Kevan Nason" <knason@emeraldis.com>
writes:
>
> After a couple years of 'listening' I've finally joined.
> Thank you all for your help -- even if you didn't know you
> were giving it. I'm still learning some of the basics
> and thought y'all might help out again. I'm new to using
> an antenna analyzer. Used to simply use the SWR bridge.
>
> I'm constructing an inverted L for 160m and am unsure of how
> to proceed. My MFJ269 tells me the following:
> Freq Rad. Resis XL SWR
> 1.9 45 155 13.5
> 1.7 32 28 2.3
>
> I haven't measured my ground characteristics, but judging by
> the general documentation available for this area and the
> large amount of clay around I figure its poor.
>
> My question is this. If antenna efficiency is:
>
> eff = Rrad/(Rrad+Rloss)
>
> and I don't change Rloss by running more radials or some
> such (I ran out of wire and want to play in the NAQP next
> weekend); would I be better off leaving the length as is and
> cancel the inductive reactance with a capacitor, or should I
> keep on trimming the antenna. If keep trimming, how far?
> Until Xl is zero and then match the antenna using
> a transformer or antenna tuner?
>
> Kevan
> NS4T
>
> _______________________________________________
> Self Supporting Towers, Wireless Weather Stations, see web site:
> http://www.mscomputer.com
> Call 888-333-9041 to place your order, mention you saw this ad and
> take an additional 5 percent off
> any weather station price.
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today! For your FREE software, visit:
http://dl.www.juno.com/get/web/.
|