Hi all and Merry Christmas.
Before Christmas I received my NCC-1 from Dx Engineering, noise canceler and
phase box.
I have made two antennas, none resonant antenna approx. 7.3 meter long. I
measure the impedance to around 200 ohm on 160. Thereafter I made a 2.67 ratio
transformer 200 to 75 ohm using 4 turn primary and 7 turn on secondary on a
73-mix FairRite Products 2873000202 core.After I was done I try to see if I
have enough signal this means: one antenna was approx. 30 meters (100 feet)
from my house and antenna two approx. 60 meters (200)feet from my house.
At around 1300 local time that is "middle" of the daylight ours and supposing
the most quite time of day, I did my test. I could see the signal increase on
my receiver (none NCC/1 connected yet) with approx. 5 to 6 db when I connect
antenna that was closest to my house and about 4db increase on noise floor on
antenna that is most further from my house. The different I guess is due to
local noise from my house and garage.According to ON4UN book, this is a good
method to use. If you see increase of signal that would normally be enough.
When my Radio is on (SUNSDR pro2) and connected to dummy load I see my noise
floor at approx. -140dbm. When I connect the NCC-1, my receiver (no antenna
connected yet) noise floor increase to approx. -135dbm.
I connected the two antennas on port A and B and using 10 dB preamp on my
receiver, I then see the same noise floor approx. -135dbm or just a touch of
signal increase on the noise floor. (internal loss in NCC-1 is around 6 or 7 dB
I have heard, not tested yet.)Should I make my two receive antenna somewhat
bigger to get a bit more signal, or is this sufficient. I use one ground rood
and use two radials that has the same length as the antenna itself. I mad the
system "portable" so I easy can move the element when I test. My antenna is
made with 1.5mm wire and the support is made of 6 meter (20 feet) fiberglass
fishing rood and 2x2 inch wooden post. Both antenna is feed with approx. 300
feet of RG6 coax.
When I test the antenna on 80 and 40 meter band it all seems ok but, on 160 I
haven't got a signal that is weak enough yet :-) The noise floor now in the
evening is approx. -124dbm
Anyone that have suggestion or comments.
"antennas mounted in bad wheatear do always perform best :-)"
(off course it start to snow that day :-)
73 Rune LA7THA
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