[RFI] 40khz Oscillator for ultrasonic dish testing

[Charles Plunk]

Unfortunately I painted the dish black many years ago....

On 5/31/21 5:33 PM, n0tt1 at juno.com wrote:
> 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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