[Boatanchors] T/R switch question _ 221122

[Nick England]

B&W type 377 coaxial T-R relay name changed to type CR-115, works on 48 to
120 vac
https://usermanual.wiki/Manual/BWCatalogue.1522491327.pdf
page 19

For muting I have just used a common DPDT 115vac relay with the coil in
parallel with the T-R coaxial relay - for receiver muting, lighting up an
"ON AIR" sign, whatever you need.
Something like this can often be found at hamfests for a buck or two.
https://www.zoro.com/omron-general-purpose-relay-120v-ac-coil-volts-square-8-pin-dpdt-ly2n-ac110120/i/G2396624/
Often seen in an octal socket version,
https://www.surplussales.com/Relays/RESealPI-1.html

I put the extra relay in a box wired to a barrier strip for easy
connections.

Nick England K4NYW
www.navy-radio.com


On Wed, Nov 22, 2023 at 8:53 PM corner5 <corner5 at comcast.net> wrote:

> hi all,
> .
> I am new this group as well as new to the world of BA.  I am starting to
> collect pieces for my new (to me) BA station and have a couple of
> questions about T/R switches.  I currently have two of them and seek
> advice how best to use them.
> .
> Switch-1 == B&W model 377B.  The coil tests good (800 ohm per spec), but
> I am unable to confirm what voltage to apply to the coil to toggle it
> (AC, DC, value?).  The coil is labeled as follows: "C.P. Clare & Co E.C.
> Coil Relay Turns 11800 ohms 800 ohm 37E.C., 462-1391-2".  This may need
> 115VAC, but I wanted to check so as not to fry the coil.  What voltage
> to use or how to determine same?
> .
> Switch-2 == Not labeled as to model but clearly resembles the classic
> line of Dowkey units.  This unit's coil is nicely labeled as wanting
> 115VAC and it works fine.  I have studied up about best practices
> relating to toggling between a BA transmitter and separate receiver, and
> have noted that it is recommend to utilize the secondary relay set (not
> the primary RF one) to mute the receiver ideally just before switching
> to the transmitter.  But... this particular Dowkey (no model ID) does
> not have the secondary relay contacts.  My question here is if it is
> still safe to use this T/R switch for this purpose?  If the muting is a
> must, can I run a secondary relay for this need.  This last has me a bit
> unsure due to exactly how to simultaneously toggle both relays.
> .
> I don't want to over complicate this, but I am trying to build on little
> funding yet still want to do it correctly.
> .
> thanks for any advice.
> .paul.
> .
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