I was unable to retreive any of the documents on the LOFAR website, so I
can't comment on the details.

I do see that the Sky and Telescope article mentioned the work at Ohio
State. This one is working at S band (3 GHz +/-) and is currently detecting
TVRO satellites and the solar emissions. I'm not sure what type of antenna
they are using, however.

I built the first prototype of the OSU system some 17 years ago, by the way,
as my Master's thesis, so I think I am qualified to comment on this. The
bandwidth of the LOFAR system is huge, percentage wise. There are a number
of problems that have to be overcome to get this to work in addition to the
RFI problem. I was able to ignore most of these problems in the prototype
because I used a very narrow bandwidth (just a few kHz). Unfortunately, my
thesis is not available on-line, but there is some information on this and
the current desgin at www.bigear.org.


Are they perhaps using circular polarization? There is an advantage to this
as most of the 'noise like' signals are randomly polarized.

As far as the VHF signal interference is concerned, it can be shown that
most VHF signals arrive at elevation angles of 15 degrees or less, so
perhaps they designed the antenna elements to have nulls at this angle.

--
Jim
N8EE

to email directly, send to my call sign at arrl dot net
"Fractenna" wrote in message
...
See article at
http://skyandtelescope.com/news/article_1334_1.asp

My educated opinions on this matter are as follows--thisreport is very
sugar
coated: The Dutch decision broke up the original consortium and, in my
opinion,
severely degraded the success as originally outlined. The astronomical
community is not happy: this is the first time that an international
astronomy
community has worked against itself.

This is NOT 'LOFAR' as defined, but a highly compromised derivative
version.
Holland is a very poor site location for these frequencies, because of the
high
population areas and extant HF/VHF use. Also, the cross polarization
inverted
V element is a poor antenna for the relevant passband.

A good link on the original plan is:

http://www.lofar.org

73,
Chip N1IR