[RFI] 40khz Oscillator for ultrasonic dish testing

[n0tt1 at juno.com]

Chuck et al,

For a super accuate method of tuning up a US dish you may want to try
this:
Use a flashlight some distance away (even 50ft)
from your dish that is in a darkened room.  If your dish is even remotely
reflective
(think clear plastic) there will be a definite spot of light at the focal
point when the
dish is pointed at the flashlight (or other single light source).  The
spot should fully cover the transducer, i.e., not be a small spot.

73,
Charlie, N0TT

On Mon, 31 May 2021 16:02:46 -0500 Charles Plunk <af4o at twc.com> writes:
> Sit down and whipped up a 40khz oscillator. If nothing else gives me 
> 
> confidence the dish is working. The dish is pretty much spot on and 
> if 
> go by max signal its very accurate at 30'. At some point need to 
> make 
> taps on the dish circuit for measuring max signal to make sure the 
> detector is in the right position in front of the dish. I'm guessing 
> it 
> is close.
> 
> https://www.facebook.com/media/set/?set=a.107413994889511&type=3
> 
> Chuck
> W4NBO
> 
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