Hi Guy and fellows TopBand lovers
It is much more them balanced feed lines. The Quad Delta Flag Array is a
revolutionary RX antenna, high efficiency and easy to implement in a
relative small real state.
Dr Dallas also did huge advances on FLAG theory; check his site Dallas files
for Flag theory and others developments like the QDFA.
http://www.kongsfjord.no/dl/dl.htm
Before the QDFA there were several antennas with deep nulls, F/R F/S etc.
However over < 50 db F/R attenuation is not common.... ok, it is deep but
some antennas can do it, BUT not 180 degree wide and from 0 to 90 degree
elevation. The QDFA is actually 8 verticals in phase and in the same line.
Dr Dallas optimize the QDFA for max F/R but it can be optimized for max RDF
too.
That is music for my ears. I see a FLAG antenna as 2 phase verticals and my
Waller Flag as 4 small verticals in phase. The phasing system is quite
simple and broadband usefully from 1.8 MHz to over 18 MHz.
There is a 20 db loss on this kind of phasing and it brings additional
complications with common mode noise that Dr Dallas fixed using low cost
speaker wire. Dr Dallas uses Radio Shack # 278-1104 and is $19.99 for a 100
foot spool. Twisted pair beside inexpensive eliminates the need of chokes in
most part of the system.
Imagine the flexibility to turn the WF in any direction, and the possibility
to install it 100ft high or 200 ft high.
Doug NX4D just upgraded his WF now it is 50ft wide by 24 ft high, and the
performance on the first day was amazing. Doug still lives in the same 1/3
acre lot and just worked his country #246 on TopBand. He started with RX
antennas in 2003.
What about WF arrays. Well... these can delivery RDFs over 14 db. This is
exciting and pure fun, there are a lot of new things to do and discover on
RX antenna for most of us, limited in suburban small lot.
Go ahead and do it!
Because the best RX antenna in the world is the one you can use.
Regards
Jose Carlos
N4IS
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