You have done well in identification of issues regarding dishes.
I am not the dish expert here and can only state my decisions in a
complex ongoing discussion.
I run ME-62 pointed in for two reasons. Better wind resistance and
because the 62 is not an omni at high freqs I figure I reduce out of
phase cancellation by pointing it in. Both ways are being done.
I run without a barrier because I do not want to divide the dish in
half and therefore double the minimum frequency at which the dish
will generate gain. Obviously both are done.
The pzm issue gets more complex and I am not the one to go there. I
like pzm for some things but do not use it within my dish. Anything I
volunteer here would be anecdotal at best as of right now.
Rich Peet
--- In "1gdw" <> wrote:
> Members,
>
> I have no experience with building microphones but would like to
> make a parabolic using the Telinga dish. I have been thinking
about
> both a Stereo and Mono design, following the previously posted
> diagrams for a home made unit.
> For the Mono setup;
> If I use a mono mic such as a ME-62 ( I have a K-6 power unit),
> would I be compromising the microphone efficiency if the mic was
> orientated to point away from the dish? The reason for that
> orientation would be to accommodate the K-6 element of the mic and
> keep the unit within the lip of the of the dish.
> For the Stereo;
> I will be using nosier lapel electric elements.
> First idea: Would there be any benefit if I used a small 1 1/2 inch
> boundary (mounted perpendicular to the dish axis ) and mount the
> elements as a PZM.
> Second idea, if the PZM idea has no merit: Would you expect the
pick
> up field of a cheaper omni to be uniform in shape? Should I face
> them into the dish or away from the dish .
>
> A second thought about the stereo parabolic. You folks have me
> confused about using a barrier in the dish, is the barrier in
Lang's
> most recent photos acting as a PZM? Is the barrier simply
> reflecting the wave to a new path and the mic diaphragm is large
> enough to gather all the semi focused wave? Perhaps the setup is
> relying on the efficiency of the mic to offset any loss of gain,
> since the mic is not at the focus point. How far from the focal
> point can you move the mic elements?
>
> 1GDW, Gerald White
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