That's a pretty tight focus for a pan.
John
--- In Mitch Hill <> wrote:
>
> Hi John,
>
> Thanks for your time to respond...
>
> I'm a great tinkerer and do-it-yourself sort of a guy, I get great pleasure
> of doing my own thing and then refining it and doing it again most likely
> based on what, hopefully, I have learned along the way...
>
> Actually, my first stab at building a dish microphone is already
> underway... Quite by chance, I came upon a source of inexpensive stainless
> steel woks, 16" diameter... This is made of a light weight stainless made
> the same way many stainless cookware bowl shaped items are made and
> surprisingly, this wok has a good parabolic shape and when pointed at the
> sun, sets a stick of wood on fire at a point 5 5/8" above the bottom center
> of the bowl... This was a very crude test made to determine how well the
> wok would focus and at what height above it the point of focus was located.
>
> I have not measured and calculated to see how true a parabola it is,
> however for a first attempt, to see what I can learn as an experiment, I'm
> going to mount a microphone on it and see how it does.
>
> In the long run, to my way of thinking, stainless would be too heavy a
> material for portability, however if this foolish wok proves to have the
> right shape, it will make a good mold for plastic or fiberglass fabrication...
>
> You can see 5 photographs of my test and result made this afternoon here:
> http://www.4shared.com/dir/2_X_hmub/Dish_tests.html
>
>
>
> In
>
> At 03:04 AM 7/17/2010 +0000, you wrote:
> >Hi Mitch,
> >
> >Building a parabolic system from scratch could certainly be fun, but
> >unless you need something bigger than the Telinga dish, $150 for the raw
> >dish is a good value for the base of your system. I did, however, make a
> >dish for less than five dollars by finding a scrap piece of ridged foam
> >insulation, cutting out overlapping rings, gluing them together, shaping
> >with a wood rasp, sanding, and then using wood glue to glaze a reflective
> >surface. First though, I calculated the shape, and cut a parabolic arc
> >template out of plywood. For my Telinga dish, I used a variety of parts
> >from the plumbing section at the hardware store to mount the dish.
> >
> >John Hartog
> >
> >--- In Mitch Hill <fmhill@> wrote:
> > >
> > > Dan,
> > >
> > > Thank you for the information And thanks to Paul for your comment.
> > >
> > > I think one of the first sites I visited in my search on line for
> > parabolic
> > > dish microphone information was the NatureSongs web site and I listened to
> > > the comparison recordings made with the ME66 (which I have and use) and
> > the
> > > Telinga dish and it is truly impressive. If I were interested in
> > > purchasing a complete system of that type, there is no doubt in my mind
> > > that is what I'd purchase.
> > >
> > > However, a key part of what my plan is a learning experience... In the
> > > past I have worked with refining a design of a hand held diver pinger
> > > locater used in underwater work which was a very similar looking device
> > but
> > > much smaller. As a result I have some experience and ideas of my own that
> > > need to be exercised before I'm satisfied that I goofed and my fall back
> > > would be a Telinga parabolic dish setup. It is definitely a neat clean
> > > design and the sample recordings are impressive to say the least, gives me
> > > a mark to aim for performance wise.
> > >
> > > Thanks,
> > > Mitch & Shadow...
> > >
> > >
> > > At 10:34 PM 7/15/2010 -0700, you wrote:
> > > >A few years ago most of the parabolic dishes were home-brewed. Now that
> > > >Telinga in Sweden manufactures a superior system, you can buy it off the
> > > >shelf. Telinga( http://www.telinga.com) is imported by Doug Von Gausig,
> > > >http://www.naturesongs.com. I do the repairs in the U.S.
> > >
> > > --
> > >
> > > Thanks,
> > > Mitch & Shadow...
> > >
> > > http://www.4shared.com/dir/UTASxktL/wildlife.html
> > >
> > > Shadow's area: http://www.4shared.com/dir/ecfWjyZb/Shadow.html
> > >
> > >
> > >
> >
> >
> >
> >
> >------------------------------------
> >
> >"While a picture is worth a thousand words, a
> >sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
> >Yahoo! Groups Links
> >
> >
> >
> --
>
> Thanks,
> Mitch & Shadow...
>
> http://www.4shared.com/dir/UTASxktL/wildlife.html
>
> Shadow's area: http://www.4shared.com/dir/ecfWjyZb/Shadow.html
>
>
>
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