Topband: Change in 160m conditions
JC
n4is at comcast.net
Thu Nov 9 08:28:17 EST 2017
>>
It seems to me that DX conditions have been pretty poor for the past 10
years on 160m . . .
<<
Hi Roger
I see your point on things changing. However I have a different experience.
The noise is up. Every day there is a new "thing" that used FVD, switching
power supply and the LED's.. oh boy the LED's that generate noise up to 50
MHz
Old antennas practice does not work any mote the way it worked 10 years ago.
Null canceling , deep front back, and other "simple" to achieve is not
enough.
The last 10 years has been very different, check the K9LA presentation on
WWROF archives how long the deep of solar cycle last. Carl shows the last 5
cycles last 2 years between less than 20 SSN. The last cycle 24 last almost
5 years, see page 8 here;
http://wwrof.org/wp-content/uploads/2017/10/WWROF-A-Look-at-Propagation-for-
the-2017-2018-Contest-Season-pdf.pdf
The actual cycle may be longer and better than 2007, 2008, 2009, and 2010.
I started on 160m in 1970 , for me, and the ones with new antennas with 12
db RDF or more, the last 10 years was the best ever on 160m, and here is why
I say that,
1- I worked #294 countries in the last 10 years and I heard #310, the 16
countries I missed was because my 1500w was not enough to be heard on the
other side. (lack of RX antenna on the DX side)
2- NX4D, Doug worked # 305 and heat probably a dozen more on the last 13
years.
3- The Waller Flag horizontal can dig signals 20 db below the same noise
from the vertical TX antenna.
4- I live in a city lot with noise from everywhere. All my 160m antennas are
in my back yard 100 x 150 ft.
5- Doug also has noise on the sub-division and live on 1/5 acre lot.
6- I know, and personal helped more than 50 WF installation and all antennas
is performing as my original WF
7- The extra 23 years on the deep cycle 24, 2009,2010 and 2011 provided a
large number of long path SSW/SSE openings with south Asia. I experiences
hundreds of days with openings. The SSE/SSW path will be open soon.
8- Low RDF antennas does help and it is a game change, a simple FLAG, EWE,
K9AY, SAL , all near 8 db RDF doe hear station Q5 that you can't head on the
TX antenna, however 2 flags, EWE, K9AY in phase can increase the RDF near to
12 dB and you can dig 8 to 10 db more below the noise flor.
9- 1db increase on the RDF increases 2 db or more noise figure, it's a
measured number with real antennas and signals on the band, not a simulation
on EZNEC or calculations. you can measure it too.
10- For the new generation using digital FT8, the improvement is the same, a
HWF can improve a signal -19 db to a +1 db. it means you are missing
another 20 db layer of weak signals without high performance RX antenna.
It point is :
You don't know what you are missing if you don't have anything to compare
with.
Get a high RDF RX antennas! You can't have enough.
The deep of cycle 25 can last 6 or more years, think about that. We are just
at the door.
JC
N4IS
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