From: william edmondson (w.h.edmondson_at_cs.bham.ac.uk)
Date: Wed Sep 29 2004 - 07:50:32 PDT
Hi Paul, all.
Geometric mean or otherwise - sure - but away from the main frequencies.
The fact of pollution there caused by our satellites is our problem,
not ETI's.
However, I would suggest (and keep my head low immediately afterwards)
that if we know the characteristics of the source(s) of the RFI we can
deal with >that< RFI in the processing. Don't forget - we know what
pulses we look for, and we know about the navigation satellite's
emissions. Or is that simply not feasible?
Cheers
William
On 29 Sep 2004, at 14:13, Dr. H. Paul Shuch wrote:
> william edmondson wrote:
>
>> the radioastronomy service has primary status in the
>> band 1660.0-1670.0 MHz (this for the 2 OH main lines). (Quoted from
>> Gerard)
>
> Not that this "primary status" has afforded us much protection from
> Iridium interference.
>
>> So - we may be looking at the wrong frequencies. We'd have to think
>> about where to look instead, and one "obvious" (??) place would be
>> the 'mid-points' of the H/OH pairings. 1542.9025 and 1543.882 MHz
>> These are nicely near each other, and bang in the middle of the water
>> hole.
>
> And, unfortunately, BADLY polluted by the swarm of navigation
> satellites blanketing the Earth with RFI! But if we ignore that for
> just a moment, I would respectfully suggest that the geometric mean
> makes more sense than the algebraic mean (for reasons I can delve into
> later). Thus, the two mid frequencies should actually be 1538.032 and
> 1538.936 MHz.
> It's also worth considering the geometric mean of the two main
> hydroxyl lines, which comes to 1666.380 MHz.
>
> --
> H. Paul Shuch, Ph.D. Executive Director, The SETI League, Inc.
> 433 Liberty Street, PO Box 555, Little Ferry NJ 07643 USA
> voice (201) 641-1770; fax (201) 641-1771; URL
> http://www.setileague.org
> email work: n6tx_at_setileague.org; home: drseti_at_cal.berkeley.edu
>
> "We Know We're Not Alone!"
>
>
>
Dr William Edmondson
School of Computer Science
University of Birmingham
Edgbaston B15 2TT
UK
Voice: +44-121-414-4763
email: w.h.edmondson_at_bham.ac.uk
This archive was generated by hypermail 2.1.6 : Wed Sep 29 2004 - 08:15:47 PDT