Topband: Dumb radial question

[Vanderydt Theo]

Hello TopBanders,

I have a (probable) dumb question about my radial system.
This summer i got rid of my inverted L antenna and put up a shunt fed 
,toploaded, tower
to use on 160. Not having time to lay down radials right away i tuned the 
vertical without
and got it at 1.2/1 SWR X 0 and about 50 Ohms. None of these figures tells 
anything about
performance of this radiator, i know! But i'm giving you the numbers for 
reference.
These are the figures i got from my MFJ analyzer.
Today i drove a copper rod into the ground at the base of the antenna and a 
number of radials
have been layed on the lawn. The ground rod and radials are attached at the 
bottom of the
vertical.
Now i read following figures from the analyzer.
SWR 1.5/1 X 0 and R 80 Ohms. Bandwith stayed the same at about 60 KHz. SWR 
went up a bit, but what i'm puzzled with is the increase
in impedance? Is it normal to see a higher feedpoint impedance? I expected 
the impedance to drop..
Am i interpreting the numbers correctly? Should i continue to attach radials 
untill i'm reading a 50 Ohm
impedance?
Maybe someone can answer my question.
Before i had the ground rod and radials i worked some dx with this antenna, 
it radiates, but
how efficient?

Thanks on forehand,
You can reply of the list to on4atw at skynet.be

73' de Theo ON4ATW - OR2T