[Milsurplus] R-720 AN/URH-2 ??

[Nick England]

 Based on the use and the front panel markings here's what I think - there
are multiple running-time counters which read in 1/1000's of an hour. A
counter was turned on when the relative signal strength was between limits,
so the net result is you could tell what fraction of the total time that a
signal was at a particular level. It is hard to tell from the photo but it
looks like the counters might be
0-20dB, 20-30dB, 30-40dB, 40-50dB, 50-60dB, 60-80dB, over 80dB, total time

Here's what I got from an engineer who used this receiver/recorder -
"I remember that receiver because we used it at VLF monitoring stations in
the Pacific area and it was used with Esterline Angus chart recorders. That
was 60 years ago so I remember little more. I was sent all over the Pacific
area to establish sites for the monitoring stations. This was all under the
direction of Jack Pierce of Harvard."
"The monitoring stations were established to determine the VLF signal
strengths in the Pacific area. This was necessary to determine the feasibly
of communicating with submarines and if the signal strength was adequate
for underwater navigation. I set up stations at Shemya Alaska, Hawaii,
Fiji, New Zealand, Australia, Jakarta, Philippines, Japan and Wake Island."

Nick England K4NYW
www.navy-radio.com

On Wed, May 2, 2018 at 11:15 AM, Nick England <navy.radio at gmail.com> wrote:

> Does anyone have access to MIL-E-16132 ??
> There used to be a web site with free downloads of mil-spec documents but
> all I find are pay sites now.
> This document concerns the development of the AN/URH-2 VLF
> receiver/recorder.
>
> Thanks
> Nick England K4NYW
> www.navy-radio.com
>
>
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