Charlie considered using a mounted green laser sight. During the winter months
when the Sun goes down it makes it very difficult to see where you're pointing.
If I remember correctly, green seems to produce the most noticeable color for
day and nighttime spotting.
Be safe,
Mike
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On May 13, 2021, 6:12 AM, at 6:12 AM, Charlie Delta via RFI
<rfi@contesting.com> wrote:
>Hi Mike
>I have studied the various datasheets for Ultrasonic receivers. Most
>have a broad beam width that is something like more than 60 degrees.
>This includes the widely used Kobitone transducer. I have check many
>datasheets including those from Murata, Monacor, Kobitone and those
>from many expensive USA made sonar transducers. All seem to have
>similar sensitivity figures all the Kobitone transducer appears to be
>6db more sensitive. I just assumed that the perfect FD ratio with the
>perfect parabolic shape when combined with the broad beam-width would
>be sufficient to flood the transducer.
>I will be using a laser beam and LED endoscope light source and I will
>test all of the variables as I have some time.
>I have also been informed that the Radar Engineers unit uses the 25khz
>frequency rather than the 40khz frequency. This apparently makes a big
>different in the usable detection range. So the assumption that 40khz
>would produce similar results to the RE unit is clearly incorrect since
>the lower detection frequency would have a propagation distance
>advantage.
>73CraigVK3OD
>"One aspect of the design that may be
>overlooked is the beamwidth of the
>ultrasound transducer itself. Even
>with a proper F/D ratio, the transducer
>may not fully illuminate the reflector
>or instead spill over the edge, both reducing
>gain. The transducer's sensitivity is
>another obvious factor. Getting the perfect
>reflector geometry won't mean much if
>it's not matched to the transducer beamwidth.
>
>Mike, K8CN
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