Topband: NEW HORIZOTAL DUAL FLAG ANTENNA " HWF" by N4IS

Fri Apr 24 07:47:40 PDT 2009

Hi low band lovers

I'm happy as I was when I got my first 6V6 tube transmitter working at 15
years old.  After almost 3 years working on dual Flag antennas I hit
something big here.

My BWF , Big  Waller Flag with dual  20ft x 14ft loops is still delivering a
solid performance on low bands, I worked during 2007 # 163 and 2008 #155
countries on Top Band from my 1 acre city lot QTH. 2009 is not so strong and
propagation is diving due this low solar activity, however I managed to work
119 since Jan 1st   on 160m.

The big news is about my new Horizontal loop. The HWF performance is just
unbelievable, is very quiet and does not pick up any man made noise, power
line noise, The city noise in increasing with all new appliance and modern
LED, LCD,  solar panels, chargers etc. I'm glad I found this new weapon.

End of January I put the HWF on top of my TX antenna at 116ft high. I'm
using the 40ft boon as top hat and part of the TX antenna. The antenna
worked very well since the first day, but after the first raining day I had
problems with the isolation between the loops and the boom, sparking,
arching and burned the two resistors. I fixed all those things last week
after returning from a 3 weeks trip.

Here what it is important to know.

1 - Choke the feed line at the phasing transformer and at the end of the
feed line close to the ground or inside the tower.

2 - For best performance on 160m I recommend 300 sq ft loops, this will work
well 160m, 80m 40m and 30m. 200ft is good on 160m and excellent on 80m,. I
tested 175 sq ft loops and also works well on all low bands but it is thermo
limited on 160m, however if your local noise is high the HWF will be a huge
improvement on your  RX system.

3- Horizontal RX antenna is not much affected by vertical TX antenna.

4 - Only one external preamp is enough for a 300 sqft loop.

5 - Grounding and chokes to avoid common mode noise is a MUST.

6- Using the boom as part of the TX antenna, the loops must be very well
isolated from the boom.

7- I'm using 2 Norton preamps with MRF151a, close to the radio, they are
quite and have good IP3, 20 db gain is only what you need, my RX is a IC7800
and  the internal PRE1 plus 2 Norton, I get 4 db noise figure on 160m. You
can find information on Dallas files about noiseless Norton preamps.

The main reason why this antenna works so well is the rejection to vertical
signals, almost 30 db attenuation on the front lob for vertical signals. The
signal noise increase > 15 db in comparison the original BWF vertical. As a
result the power line noise does not impact my signal noise any more. 

On 80 m I can hear signal from Europe 2 hours before my sum set, Q5 s5 to s6
signal on the HWF and no copy at all on my BWF, vertical.

On 160 m I can hear signals Q5 from PY, ZP VK, ZL when there is no way to
even detect a signal on my BWF. During the night when the signal is out of
noise, the signal is stronger on the BWF.vertical.

The propagation plays a lot and if the signal is coming bellow 16 degree and
vertical polarized the HWF does not copy it at all, so the solution is to
use both antennas one vertical and another horizontal.

I will update my web site by the end of the summer with all tests and
photos. 

Some friends is getting fantastic results using one single horizontal loop
20 ft above ground, when local power line noise is a problem. PY2DO Daniel
few weeks ago was able to copy VK9 and YC0 on 160m with a single loop and no
copy on other traditional RX antennas.

This kind of antenna can be easy to built using hardware from 10m yagi, I
tested HWF's with 20ft boom, 24 ft and 40 ft, all can perform well but
limited by your local noise. Bigger is always better.

My intention is to motivate the low band fellows to test and help to develop
this new solution for city lots, imagine how many DX stations can improve RX
on 160m, and be active from rare location with a lithe real state. All
information is available on my site.

www.n4s.com <http://www.n4s.com/> 

George AA7JV is thinking in develop a small RX rotatable antenna for HF, to
cover 160 to high bands, easy to turn and use during DX expeditions, so more
improvements is possible to come soon. 

New papers, tests and new models like a dual delta flag was done by Dr
Dallas; you can find a lot of new information on Dallas files

http://www.kongsfjord.no/dl/dl.htm

I would like to thank Dr Dallas for his support and important work on
developing and testing the Flags, He and Doug NX4D have supporting me and
sharing information's and doing tests on Flags, without Doug and Dr Dallas I
was not able to reach this level of signal noise on my RX system.

I'm still living in noisy city lot but I can enjoy low band good as never
before. 

Please try new things, like a big 30ft x 20ft dual loop on 50ft boom at 120
ft high, this monster HWF can performs well as a full size 160m 4 elements
yagi. I have no tower to support this size of antenna.

Also don't panics for the mechanical problems, a simple wire supported by
nylon and a good 2N5901 preamp will get you on low bands with a good RX.

Good tests.

Regards

JCarlos

N4IS 

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