Hello,
I have constructed 4 dual-wire beverages so I have coverage every 45
degrees.
Just finished the shack control box, so I have 8 leds and a rotary switch to
select
the appropriate antenna, or search for where the guy is coming from.
In the woods, I have built two control boxes (virtually identical) and run
the control
voltage on the feedline (none, +12, -12, and AC) to switch between 4
antennas (2 dual-wires).
Then, outside the shack, I have another relay that selects wood's control
box A or B.
One coax coming in the shack.
The electrical part of the system works just fine.
Here is the experimental part:
Box B is 200' feet away, Box A 150' away from the shack. I fabricated 200'
of 450 ohm open
wire line on box B back to the external relay outside the shack. Box A has
75 ohm RG-6.
Of course, all impedances were matched at the control boxes, and to
transform the open wire
back to low impedance at the shack end.
I am testing on 40M now during the day because of convenient signal
availability.
The problem: the open wire feed has some sort of constant noise, like
normal background hiss.
Box A is virtually dead quiet. I wound two different transformers at the
external relay point,
and both exhibited this noise. I use binocular cores with Teflon tubing to
isolate the primary
and secondary windings. I use this same technique of winding transformers
throughout all
beverages and control boxes. The PEAK signal levels from the open wire
system (box B), seem to be about the same from the quiet system (box A).
i.e. - a station NE(box A) shows S-9 and the N
(box B) shows about S-9 also. NE has S-1 noise, N has S-5 noise.
Is this because the RG-6 is on the ground all the way to the shack and the
open wire line is
8-9' off the ground?
73's
Glen K4KV
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