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Hi to all,
here same news about receiving antennas and same questions.
So, like many of you know i like to check the ability to improve the S/N
of receiving antennas, finding wich is the performance of all the last
project discussed here.
Now i have in my field, an EWE, the shielded phased loops, one beverage,
a magnetic loop, plus the trasmitting slooping dipole, all on the North
America, and soon i'll put a K9AY.
So, wich is the problem??
The problem is that year after year, the local noise is increasing, and
exatly at 310=B0 there is a local noise that i receive on all my antenna
sistem, it is shure a local noise, and on the beverage is really strong,
a little bit less on the phased loops, and a little
bit less again on the EWE, that seems the best in S/N, with this local
signal.
So now the questions.
Reading the "The beverage antenna handbook" by Misek, third edition, at
page 5 him more or less wrote:
locally generated electical noise from appliance etc etc etc man made
noise is propagated in vertical polarizazion, and lessloss soil may
help you to dont pick up this ground wave signal
So him suggest to put under the beverage a wire to stabilize the soil,
and expecially for have a lessloss soil that help to dont pick up local
signal coming through ground wave!
So, someone have made same test in this direction?? this point i
believe is very important to reduce the near noise, but how many amateur
have the wire under your beverage?
In wich condition the soil is poor, or lossless?
Another question is again on trasformer, becouse after many and many
message here, i dont have understand if the best solution is connecting
to ground the cable togheter with the beverage ground, or made a
separate ground at about 40 meters from it, or leave left it.
I have made in this 3 last years many type of trasformer, starting with
trifilar winding like ON4UN suggest in his book, after i have made it
with two-hole core with a u of 10.000, with very good results in loss
and ros, and the last i have used a pair of single hole core long abt 2
cm., and i have coupled it like the two hole core, the u was abt 2700,
the loss was 0.15 db, and ros better of 25 / 30 db ranging from AM to 15
mhz.( all the test was made by a network analizer by HP)
So all my trasformer is winding like an ac trasformer, with two
separated winding, and it is connecting togheter in one end, and then
put at ground level.
For my experience, this type seems more simple to made, and the ros
performance seems more better than the other made on normal toroid.
So when a traformer have low loss and good ros, have many important is
the sistem of winding it?
Well, i hope that someone may answer to my question, for the moment,
best DX to all, and here in Europe we are waiting for same station from
south America, for us spring summer season!!!
Many 73
Giulio IK2DED.
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