[CQ-Contest] ARRL fieldday reports at RBN (reversed beacon network)
ulli.grunow at ospreyribs.com
Sun Jun 23 11:00:28 EDT 2013
Dear Hamradio friends contesters and ARRL-fieldday participants,
I would like to remind you, that the so-called reversed beacon network (RBN)
is a great tool, to confirm, whether your antenna set-up during ARRL field
day was effective.
Please check the spot analysis tool at RBN:
Main site is here:
After the contest you can check the signal to noise ratio the various
automatically operating CW skimmer receivers report. As everybody is using
identical software and many even using same hardware (the great QS1R
receiver by Phil Covington), the figures reported can be compared.
You should have in mind though, that band conditions can be very different,
if station QTH are separated more than probably 100miles
If you check your figures at my skimmer station (ON5KQ) , here is my antenna
160/80m: 200m longwire at 3m high, end-fed with 1:4 impedance transformer
and 20db pre-amp.
40m: 8ele vertical array made of resonant quarter wave elements, 100radials
per element (approx.. 8km of copper wire covering 3000m2), at European
night-time direction is to NW for USA, at EU-daytime until 21h UTC direction
is to east
30m: resonant half wave dipole at 15m, main direction east/west, 500kHz band
pass filter (-6dB) plus 18db preamp (homebrew),
20m: resonant half wave dipole at 15m, main direction east/west, 500kHz band
pass filter (-6dB) plus 18db preamp (homebrew)
17m: using the 20m antenna, in parallel to the 20m band pass there is
another 500kHz band pass filter for 17m (-6dB) plus 18db preamp (homebrew),
surprisingly this set-up works very well, although no resonant antenna is
used and very high SWR on the feedline
15m: 5/8 wavelength vertical over same radial network as used for 40m array
12m: 5/8 wavelength vertical over same radial network as used for 40m array
10m: 5/8 wavelength vertical over same radial network as used for 40m array
Still this rx-system is not yet ready and needs to be improved !
The big problem is, that I don't use power combiners yet, but all antennas
are brutally coupled together with T-fittings of PL-connectors. As soon as I
have time to install the power combiners, I will do so, which will improve
the pattern of directional antennas very much and prevent that some bands
face power losses due to interaction of different antennas.
I carefully designed the 5/8 wavelength verticals not to interact with the
very close 8ele 40m array.
For the winter a very comprehensive 8 direction 2ele beverage array will be
setup during the summer - so hopefully I can offer a very effective skimmer
station for the low-band season.
Unfortunately, I have to switch off the whole skimmer system, when I am QRV
myself. So if I am in the contest myself, we should better gain QSO-points,
as operate the computers.
rx: single QS1R (no other receivers used yet)
computer: Supermicro dual quadcore Xeon workstation (during weekends &
contests), during the week, when there is lower activity only 10year old
Pentium D is available for the moment. I plan to purchase new second
Supermicro dual Xeon workstation .
Best regards, enjoy reversed beacon network (RBN)
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