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
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