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Paddle input with Y connector OK?

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Barry

Paddle input with Y connector OK?

Is there any reason I shouldn't make a "Y connector" so my CW paddle can
be input to the K3 and another radio (or external keyer)? Yes, only one
will be on at any given time.
Tnx,
Barry W2UP

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Dick Dievendorff

Re: Paddle input with Y connector OK?

I use a paddle plugged into the paddle and an extenal keyer plugged into the key input. No Y needed. If you want 2 paddles or 2 external keyers or a straight key and bug then a y is quite appropriate.

73 de Dick, K6KR

On Mar 27, 2011, at 14:50, Barry <[hidden email]> wrote:

> Is there any reason I shouldn't make a "Y connector" so my CW paddle can
> be input to the K3 and another radio (or external keyer)? Yes, only one
> will be on at any given time.
> Tnx,
> Barry W2UP
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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P.B. Christensen

Re: Paddle input with Y connector OK?

In reply to this post by Barry

Barry,

You'll either need to look at the key line input section of the schematics
for the two transceivers, or "give it a shot." In the past, I've used low
voltage-drop Schottky diodes to steer and isolate two transceivers. I now
use a W8ZR StationPro II (SPII) and no longer have these concerns. The SPII
is a great station switching device and in addition to switching the paddle
lines, it will automatically switch many other station functions.

Here's why the problem can occur when using a simple "Y" adapter: The
paddle lines from most transceivers (and keyers) are often pulled up to a
low-voltage supply voltage rail using moderately high-value (e.g., 10K)
resistors. When the transceiver is turned off, the supply rail may look
like a low-z short to ground. If an off-the-shelf "Y" adapter is used, then
the paddle contacts are in parallel with 10K and a voltage divider is
unintentionally created on the active paddle line since the paddle lines
sees 10K to the active rig's supply and 10K in the rig that is "shorted" to
the inactive power supply. That may or may not be enough to continuously
pull down the paddle line on the active transceiver and cause problems -- it
depends a lot on what conditioning each transceiver is providing on the
paddle lines.

If you find that an off-the-shelf "Y" adapter won't work, then with a little
effort, you can try installing small Schottky diodes into the 1/4" or 1/8"
mini plugs of a homebrew "Y" adapter. Two diodes are needed in each of two
plugs of the "Y" going to the transceivers: one on the dit lines, the other
on the dah lines. Better still...look into the SPII!

Paul, W9AC

----- Original Message -----
From: "Barry" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, March 27, 2011 5:50 PM
Subject: [Elecraft] Paddle input with Y connector OK?

Joe Subich, W4TV-4

Re: Paddle input with Y connector OK?

In reply to this post by Barry

> Is there any reason I shouldn't make a "Y connector" so my CW paddle
> can be input to the K3 and another radio (or external keyer)?

Yes. Most rigs have a logic level input with pull-up. Some are CMOS
(12V) others are TTL and all have some voltage that could cause
issues for another radio.

If you do a "Y" connection, at a minimum you should use diodes to
isolate the radios. However, if one of the radios uses low power
CMOS logic even a silicon switching diode will introduce too much
voltage offset for the keyer to work properly.

73,

... Joe, W4TV

On 3/27/2011 5:50 PM, Barry wrote:

Guy, K2AV

Re: Paddle input with Y connector OK?

In reply to this post by Dick Dievendorff

The problem with wire Y's in your situation will be that the keying
voltage from one rig will be across the circuitry of the other. This
is most likely an issue whether both rigs are turned on or not. It can
simply act as a shorted line to the paddle input, or it can be
destructive. Bad idea.

IF ALL the devices/rigs to be keyed present a positive voltage to key
on the paddle connections, double-diode "Y's" can be used (sometimes
called diode "Or's"). Diode cathodes are wired together and to the
key/paddle's dit/dah leads. The separate diode anodes go on to the
"paddle" leads from the rigs/keyer. Each additional device will
require another diode off the common points for the dit and dah (2
additional diodes total per additional "paddled" device).

73, Guy.

> On Mar 27, 2011, at 14:50, Barry <[hidden email]> wrote:
>
>> Is there any reason I shouldn't make a "Y connector" so my CW paddle can
>> be input to the K3 and another radio (or external keyer)? Yes, only one
>> will be on at any given time.
>> Tnx,
>> Barry W2UP
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>