naturerecordists
[Top] [All Lists]

Parabolic Reflector plus Head Spaced Boundary - Field Test

Subject: Parabolic Reflector plus Head Spaced Boundary - Field Test
From: "tk7859" tk7859
Date: Sun Mar 2, 2008 9:30 am ((PST))
Hello All

I've spent the last two weeks visiting relatives in the Odenwald, 35
miles to the south of Frankfurt.

I managed to get out for a total of some eight hours of field testing
the PRHSB.   I behaved exactly as predicted by the tests in my garden
at home.  However I found it quite difficult to aim at and isolate
individual sounds in the thickish woodland.  I'm clearly very much a
beginner to using a dish in this type of habitat. 

At the moment I do not seem able to access the naturerecordists file
site so am using Geocities for my examples - apologies in advance for
any difficulties you have downloading.

m("btinternet.com/site.jpg","//uk.geocities.com/g0sbw");">http:

gives a Google Earth view of the recording site.  This was not as
ideal as it seems - Frankfurt International Airport is only 30 miles
away and there are several military airfields in the area.

m("btinternet.com/dishsetup.jpg","//uk.geocities.com/g0sbw");">http:

shows the dish set up on the tripod.  The following is a short (1
minute ) extract of a wide stage recording.  Listen for the distinct
clicks in the last twenty seconds or so.

m("btinternet.com/wpecker1.mp3","//uk.geocities.com/g0sbw");">http:

When recording this I thought someone was close by tapping with
something.  In the last day of my recordings I got an answer.  A
woodpecker shaped bird landed on a thin (2inch diam.) bough about 30
feet in front of me at a height of about 60 feet.  It was late
afternoon on a dull day so I could not make out any distinguishing
marks.  The bird commences tap tapping (not drumming) at the bough.  I
managed to record with both the boundary and the parabolic dish
capsules.  The following, 40 second, snippet is exactly as recorded
with my statements of  "wide stage" and "parabolic" and the noise of
the potentiometer being turned.

m("btinternet.com/wpecker2.mp3","//uk.geocities.com/g0sbw");">http:

and this is a the same with the announcements and potentiometer noise
deleted.  a 350 Hz HPF as also been applied to reduce the aircraft 
and buzz saw noise.

m("btinternet.com/wpecker3.mp3","//uk.geocities.com/g0sbw");">http:

The difference between the barrier and parabolic dish capsules can be
clearly heard and can be seen in this "Raven Lite" waveform of the
wpecker3 sound snippet

m("btinternet.com/wpecker3.jpg","//uk.geocities.com/g0sbw");">http:

The field test was a success in proving the application of this
technique/method to field recording.  The test has also shown some of
the drawbacks of using big reflectors in woodland.  In turn these
problems have set me thinking about the design of the next version
which will have weight saving and portability prominently on the
design brief.

Please let me know if you have difficulties with the  Geocities FTP
site.  If necessary I will repost this with links to the
naturerecordists file depot when this is available.

I would also love to know your views on the name of the tapping bird -
clearly I'm a tyro birder as well :-)

Cheers
Tom Robinson 





<Prev in Thread] Current Thread [Next in Thread>
Admin

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU