Hi John,9V1VV
You are absolutely right...the main issue for operating topband is how to
get better and better S/N...finding a quiet place whenever possible...and
luckily...after that ...be a though one like a dog hound in the night till
morning...hearing for a new one ... hi hi
Best of luck for all of the 160M operator....
Nuradi YB0UNC
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of JC
Sent: Saturday, August 15, 2015 8:55 PM
To: 'John Davies'; topband@contesting.com
Subject: Re: Topband: Best wire antenna for roof top location.
" All of us have tried separate small loop receive antennas, both passive
and active, with only marginal improvements. Noise cancelling antennas don't
work due to the myriad of noise sources in built-up areas. Short Beverages
are a waste of time as well.
Bottom line is it is hardly worth bothering. After you have worked the few
big guns in EU and the JAs, Aussies and Russians on top band there is a
quantum leap to the rest of the world, all due to noise.
John 9V1VV "
Hi John
I understand how frustrating it is when you need to hear on the transmit
antenna. I started listening top-band back in 1970, I was able to work my
first DX in 1972 and it took me 20 years to work 100 countries. After moving
to a quiet location in 1990, I worked 9V1XQ in 1994 with 579 and using a
vertical with almost no radials, my back yard was 20 x 10 m...
The good news is that there is a solution for rooftop location. I have been
working on developing the Horizontal Waller Flag since 2009 and there are
two HWF in downtown Sao Paulo, Brazil. One at PY2XB and another at PY2AAZ.
Fabio's location is PY2AAZ-15 - 23°35.12' S 46°40.16' W - GG66PJ99QM
Fred, PY2XB, has several pictures on QRZ.com.
The Horizontal WF has two identical horizontal flags cancelling each other,
the rejection of manmade noise is above 40 db at the direction of maximum
gain. The antenna directive gain is excellent, 11,5 db RDF. But the power
gain is very low -55 db. There is over 20 db increase in SNR.
The antenna already optimized and the amplifiers still have some option
under test, the final system will only be available next year. I am running
very late on my final tests. This season there is almost no signal to use,
it has been hard to hear Europe on 160m. Very poor conditions.
Next year you can expect few articles on QST for those who want to build
them, if you google HWF N4IS or NX4D (http://nx4d10.wix.com/waller-flag)
you can find presentations and pdfs about the project. I will offer a
commercial optimized version next year. Some DX expeditions will use the
HWF from roof top as well.
With the HWF the 160, 80, 40 and 30m bands are quiet as 20m, it is a
difference experience.
Regards
JC
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