[GreenKeys] Polar Relays.

[B. Smith]

A test an adjustment jig can be found on my page:
http://k4che.com/Polar%20Relay%20Test/Polar%20Relay%20Testing.htm

K4CHE
On 2/28/2026 7:57 PM, Tom Hunter wrote:
> First - I am glad Paul Cembura stepped up with 314A relays.
> At $20 there is no need to fool with a 255A which is a stinker
> to adjust.
>
>
> Second - Al,
>
> I connect the two windings in series aiding for lower current
> and greater sensitivity. I measured the relay current from my
> RS232 at +- 9.4 mils. I had to hold the 314A up to my ear to
> hear it  chatter, yet it printed perfectly on my model 28.
>
> The 314A is a mercury wetted relay which means the contacts
> are constantly being renewed. It also means the relay must be
> kept within 30 degrees of vertical or the liquid mercury will
> short the contacts.
>
> The model 15 wiring looks like they are using .25 mfd in series
> with 2000 ohms as a contact protector for a 255A relay.
> I would also recommend using that across the 314A
> contacts that key the loop.
>
> The 314A is pin compatible with the 255A
>
>
> Tom   N3CRK
>
>
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