Please enlighten as to the possible use of the polar relay beyond land line circuits? Cathode keying replaced mechanical devices in TU by the late forties and early fifties, not being contrary and know that the polar relay has been around for a long time but have no idea why it would be used or for what? My best assumption would be that they were used to allow week currents that were on land lines to key the high current loops on the teletype printers and allow the high current loops on keyboards and perf systems to produce low current for distribution over land lines?

Ray F/KA3EKH

From: [email protected] <[email protected]> On Behalf Of B. Smith
Sent: Wednesday, May 24, 2023 11:00 PM
To: [email protected]
Subject: Re: [MRCA] Mystery Project

KM4V is correct and a tip of the Hatlo hat to him. The relay is adjusted for "Equal Time" on the pulses with equal time displayed as center on the meter. The relay has numerous adjustments and the alignment procedure is fairly complicated but most relays just need minor adjustment unless they have been Ham Hacked.   Polar Relays and their circuits are PFM.

On 5/24/2023 3:58 PM, [email protected] wrote:

Polar relay test and alignment / RTTY testing.

KM4V