From: "onna_grace" <>
>
>
> thank you both for the advice. I have decided to attempt to construct
> a parabolic myself. What is the advantage of using a white dish over
> a metalic dish? I found metallic dishes sold at:
> http://scientificsonline.com/product.asp_Q_pn_E_3053875
>
> but I get the feeling that they are not recommended for sound. Why?
Edmund Scientific also has some metal dishes, look for solar cookers.
I don't like metal because it tends to ring too much, like a bell. Even
a tiny insect will cause this. Plastic dishes damp such sounds much faster.
The dish I'd suggest is the Telinga dish. It's available as a
replacement part for the entire Telinga:
http://www.naturesongs.com/Telinga.html
The white dish on my homemade parabolic page is less desirable, not
because of color, but because of it's long focal length. A dish in which
the focus is inside the front plane of the dish will have a more even
frequency response.
http://frogrecordist.home.mindspring.com/docs/quickparabolic.html
There is one advantage of the white dish, if standing in the night on a
road shoulder recording frogs the folks in cars will see you sooner than
with the clear Telinga dish. In either case they will tend to shy away
from you as you are obviously strange.
Some also tend to aim their parabolic visually. A clear dish makes this
easier. I tend to aim mine by sound so find this less of a advantage.
Walt
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