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Re: Models of reflectors

Subject: Re: Models of reflectors
From: Walter Knapp <>
Date: Thu, 11 Dec 2003 00:51:40 -0500
From: "Daniel De Granville" <>
> 
> Hi there folks, 
> 
> I have been searching the web for some types of parabolic reflectors that I 
> could use as an example. I came across several  models used for indoor 
> lighting. They are supposed to be aluminum made, lightweight (average weight 
> below 2 lb / 1 kg) and cheap (ca 20 to 25 USD).
> 
> http://www.repume.com.br/produtos/di240.htm (diameter 52 cm)
> http://www.eletricanet.com.br/ilum_industrial/ilum_industrial16.htm (diameter 
> not specified)
> http://www.eletricanet.com.br/ilum_industrial/ilum_industrial08.htm (diameter 
> not specified)
> http://www.westarb.com.br/p_lampadas_iluminacao_ind.htm (diameter not 
> specified)
> 
> Could some of you have a look at the links, and give me your opinions whether 
> any of these designs would work as a good reflector for nature sounds 
> recordings? 
> 
> Thanks again, 
> 
> 
> Daniel De Granville
> Bonito, MS, Brazil
> 
> 

I once used such a style of reflector. For a air sonar project. The 
focus was very poor, pickup gain was minimal, but the price was right 
(free). I think these things are designed for a bulb with a linear 
filament and designed to send light from the entire filament length, 
thus the poor point focus. I'd not recommend them for a nature recording 
reflector. A large metal kitchen mixing bowl would probably be better. 
Neither are parabolic in shape.

Though I'm not sure how you would get them in Brazil, you would be 
better off with one of the aluminum large solar cooker reflectors from 
Edmond Scientific.

Or here is another supplier, and pictures:
http://scientificsonline.com/product.asp?pn=3053875

Or use a Telinga spare reflector.

Here's a photo of a diy "parabolic" to show just how far afield you can go:
http://gbppr.dyndns.org/PROJ/mil/mic/MMDS-microphone-2.jpg
That one is actually based on a radio reflector. I would guess it would 
pick up a lot from the side, but should have a fair gain.

Walt




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