<div style="color:black;font: 12pt Arial, Helvetica, sans-serif;">Everybody used them who wasn't the Navy. And they weren't all blue. Some were white, depending on the model. 27 kHz standard. 27/9 switchable optional. Eventually superseded by Orcatron, et al, which produced higher wattage units with more clarity.
<div>Vance</div>

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<div style="font-family:helvetica,arial;font-size:10pt;color:black">-----Original Message-----<br>
From: Brian Hughes via Personal_Submersibles <personal_submersibles@psubs.org><br>
To: personal_submersibles@psubs.org <personal_submersibles@psubs.org><br>
Sent: Sat, Jun 29, 2019 7:29 am<br>
Subject: [PSUBS-MAILIST] Helle Engineering frequencies or any other info<br>
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Found an obituary of the fellow who founded Helle Engineering.  My kind of guy, not formally trained as an engineer, but a curious mind and independent research led him to found a successful company building underwater com systems.<br>

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I can't find anything on the web about the blue boxes his company sold, especially the frequencies they used for through water systems. Anyone here remember them or where to find more info?<br>

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Thanks,<br>

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Brian <br>

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