The radiation resistance is 25 ohms. I estimate your base referred ground
loss resistance to be 10 ohms. So, you should expect a VSWR of 1.4:1 fed
directly with 50 ohm coax.
To obtain a better match you could place a shunt inductor (start with 4 uH)
across the feedpoint but you will have to shorten the T wires a bit.
Dave WX7G
On Jan 25, 2012 12:28 PM, <ct1ilt@sapo.pt> wrote:
> Hi Everyone,
>
> just finishing puting up a T Vertical (exactly in T shape) using 2
> supports at the ends.
>
> The vertical portion is 18m and the T is 17m to each side (34m total).
>
> I am laying radials from 20m - 40m (have about 20 right now).
>
> My question is regarding the feeding of the antenna, should it be
> straight with 50 Ohm cable? Should I make some impedance transformer?
> (I have FT240-61) that I could use.
>
> Thanks for help, getting ready here for CQ WW cw 160M.
>
> 73's Filipe CT1ILT aka CR6K
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|