Topband: 46 radials now on vertical/FT1000MP S/N observation

[n4uk@mindspring.com]

         Hello to all,
            I spent a good portion of Saturday putting up a 500 ft East/West beverage and laying out 16 more radials to the 1/4wl tower vertical. I recorded the SWR changes after adding radials in groups of four. Here is what I was seeing on the swr meter of my FT1000MP.

# of radials  1.5:1 points    Center freq.   Increase  Bandwidth
30              1778-1849         1813.5                   71khz
34              1784-1854         1819        5.5          70khz
38              1790-1857         1823.5      4.5          67khz
42              1791-1858         1824.5      1            67khz
46              1794-1860         1827        2.5          66khz

       At what point does one stop seeing a change in BW and the 1.5:1 points with the addition of four more 1/4 wl radials??     

      Also, for those of you who own FT1000MPs, has anyone made tests on the change in signal to noise ratio on 160 meters with the radio receive front end in the "tuned" and non "tuned" position menu settings? I made some tests this morning listening to local line noise and a friend 30 miles away. With the additional gain of the front end device inserted the line noise is S7 and the station is S9.A S/N of 12DB. When the Front end amplifier is removed the line noise decreases to S4 and the signal of the other station is S8. A S/N of 24db. This is an effective S/N improvement of 12 db with the front end removed on 160. Can this RF device that is removed or inserted have such a poor noise figure that it adds 12 db of noise on 160 meters??????  Obviously the receive front end is best kept in the "tuned" position which is where I usually keep it. The only problem with this is that the preamp "tuned" stage is not band independent. When the "tuned" position is menu selected to remov!
!
e the device from 80 and 160 meters another device is added to 24 and 28 MHZ that ruins the signal to noise on those bands. Is anyone aware of any way to avoid adding preamplification on 10 meters when the "tuned" position is selected short of modifying the radio and removing power from the the device???? Fun stuff!!
 Se you all next weekenbd in the ARRL 160m test. We'll be a Multiop.
   73, Ken, N4UK 
   Gray Court, South Carolina