Hi Andrei,
many thanks for your reply and the very useful informations!
==========================================
The placement of this chokes, which (I hope you have few of them for
RX feedlines) and what quality of ground rods used, may vary its
properties from FB to INCREASING noise - been there, seen that ...
--------------------------------------------------------------------
OK, may be you are right, so I disconnected one choke and also the
connection to the tower and its ground, keeping the feedline insulated as it
is with all the Pennants, but nothing changed.
But I discovered that the problem is due to the KD9SV preamplifier. I don't
know why but it introduces that s9+ noise only with the Flag, not with any
Pennant, neither with the verticals. On all them the KD9SV is a great
performer and I could not rise low signals without it.
Leaving the preamplifier out, the noise level is the same as on the
Pennants, but I can't get any S-meter reading.
=============================================
What is more interesting is F/B ratio of your antenna!
........................... The needed resistance range was from as low as
700 to 1100 ohms as I recall. All the testings was on local BC at
1134Khz (quite stable signal some 20 km away) and confirmed on 80
meters. Propely terminated flag shows about 24-26 db of F/B on a
ground signal.
------------------------------------------------------------------
Unfortunately there are no local BC stations here. The closest one is Radio
Koper in Slovenia, abt. 90 km. away, with a good strong signal on 1.170 KHz.
Daily F/B on such signal is 25 dB (from s7 to s9+15)
So the Flag works as it should.
================================================
Local NOISE SOURSE could be closer to the Flag then to any other of
your RX antenna and 'spread in direction' so it will actually mask
antennas real F/B and degrade its helpfulness.
We do have to carefully choose the antenna location ...
--------------------------------------------------------------
I agree with you Andrei, but in my situation this is the only possible
location for a rotable Flag (an existing telescoping tower with the
Tx antenna on the back in the preferred direction)
===============================================
>From my experience Falg can be used to REJECT the noise source only
and only if it is a single direction source. For getting some
directivity and more gain K9AY arrays are much better of course.
--------------------------------------------------------------
And that's what I'm going to do now.
....
Thanks for all the suggestions about K9AY loop grounding.
============================================
FireRite binocular BN202-73 is very nice, 3 and 9 turns windings is
all you need.
-------------------------------------------------------------
Yes, that has been already my choice: I found that 3 and 8 windings is
perfect!
===========================================
Andrei,
RA6LBS WWW.RA6LBS.RU
-----------------------------------------------------------------
Andrei, your web site looks interesting, but I am unable to get any English
reading on it!
Best 73
Luis IV3PRK
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