[TowerTalk] 4080V test get interesting per W8JI suggestions

[Dinsterdog@aol.com]

I have no idea why I didn't test things at the antenna but chalk it up to  
new born twins....
 
Here are the 80M results:
 
3.770Mhz                       3.789MHz                      3.826Mhz
 
42 ohm impedance         42 ohm  impedance        55 ohm impedance
 
2:1  SWR                         1.4  SWR                       2.0 SWR
 
Bandwidth at 2:1 is only 56 Khz.  Manual states 100Khz at  2:1 Had 30Khz more 
bandwidth in the shack.  Coax feedline was making a  difference here. 
 
Take the radials off and Boom!
 
3.870Mhz                       3.883Mhz    3.910Mhz
 
80 ohm impedance         80  ohm impedance        85 ohm impedance
 
2.0  SWR                        1.6  SWR                       2.0  SWR
 
40 Khz of bandwidth.........?  I thought it would go higher with a  less 
efficient antenna.  A 94Khz jump in resonant point. 
 
THE 40M results:
 
7.132Mhz                       9.972Mhz                      6.846Mhz
 
80 ohm impedance         50 ohm  impedance       48 ohm impedance
 
2.0  SWR                       1.2  SWR                        2.0 SWR
 
286Khz bandwidth as advertised, or close enough.  Resonant point  slightly 
lower by 10Khz than measured in shack. 
 
 
40M Results with No Radials-
 
7.213Mhz                     7.286MHz                          7.392Mhz
 
impedance 60 ohms      impedance 70  ohms          impedance 90  ohms 
 
2.0  SWR                       1.6  SWR                           2.0 SWR
 
Conclusion:  I still have a 8-10 ohm difference in impedance when  comparing 
40 meters to 80 meters at the feed point with or without radials  attached.  
So it is the antenna.   I had a suggestion  emailed to me that it is because 
the 80M antenna portion is a 1/4 design and the  40M antenna is a 1/2 wave 
design.  This would explain the size of the 40M  coil considering the antenna 
itself is almost a quarter wave in length for 40  meters.
 
Also, it goes to show the huge difference even a small radial field can  
make.  I use very heavy insulated hard copper wire but if you saw my  puny back 
yard, you would wonder why I am even trying a low band array. 
 
Any input on these numbers is appreciated except by SWR critics.  This  all 
about impedance and the effect it can have in an array.  If this was  just a 
stand alone antenna, I would not be putting the effort in.  Also, I  don't plan 
to operate below 7.000Mhz.  I was using an analyzer.  I  just can't wait for 
those questions. 
 
Thank you=  And thank you to those with some excellent  suggestions-
 
73
 
Paul  N0AH