[Elecraft] Elecraft K3 RX Antenna OUT termination

Sat May 31 12:20:31 EDT 2025

Terminating the Receive Antenna Port on the Elecraft K3s can be beneficial
in certain scenarios. Here's why:

1. Reducing Noise & Interference - An open port can act like an unintended
antenna, picking up stray signals and noise, which might degrade reception
quality.
2. Preventing RF Feedback - If you're operating in a high-RF environment, an
unterminated port could introduce unwanted feedback into the receiver.
3. Protecting Internal Components - Some operators terminate unused ports to
prevent potential damage from static buildup or accidental RF exposure.
4. Maintaining Signal Integrity - A proper termination ensures that
impedance remains stable, which can improve overall receiver performance.

If you're not using the port, a simple 50-ohm termination might be a good
practice to minimize unwanted effects. You might find more details in the
[Elecraft K3s
manual](https://elecraft.com/pages/k3s-high-performance-transceiver-manuals)
or other technical resources.

73,

Dick,    W1REJ

-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
Behalf Of elecraft-request at mailman.qth.net
Sent: Saturday, May 31, 2025 12:00 PM
To: elecraft at mailman.qth.net
Subject: Elecraft Digest, Vol 253, Issue 31

Send Elecraft mailing list submissions to
	elecraft at mailman.qth.net

To subscribe or unsubscribe via the World Wide Web, visit
	http://mailman.qth.net/mailman/listinfo/elecraft
or, via email, send a message with subject or body 'help' to
	elecraft-request at mailman.qth.net

You can reach the person managing the list at
	elecraft-owner at mailman.qth.net

When replying, please edit your Subject line so it is more specific than
"Re: Contents of Elecraft digest..."

Today's Topics:

   1. Re: KPA500 and KAT500 for sale (Jim Brown)
   2. K3 RX Antenna OUT termination (Rich)
   3. Re: K3 RX Antenna OUT termination (Jim Brown)
   4. Re: K3 RX Antenna OUT termination (Rich)
   5. Re: K3 RX Antenna OUT termination (Ted Edwards W3TB)

----------------------------------------------------------------------

Message: 1
Date: Fri, 30 May 2025 11:01:28 -0700
From: Jim Brown <jim at audiosystemsgroup.com>
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] KPA500 and KAT500 for sale
Message-ID:
	<25f54a22-6982-482f-adf4-0a22c52fc942 at audiosystemsgroup.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

On 5/30/2025 3:31 AM, Stephen Craven via Elecraft wrote:
> configured for 115VAC

The amp runs fine on 120V, and changing to 240V is trivially easy.

73, Jim K9YC

------------------------------

Message: 2
Date: Fri, 30 May 2025 16:58:02 -0400
From: Rich <rwnewbould at comcast.net>
To: Elecraft <elecraft at mailman.qth.net>
Subject: [Elecraft] K3 RX Antenna OUT termination
Message-ID: <d429a026-7cdd-493d-be74-64463beba0b0 at comcast.net>
Content-Type: text/plain; charset=UTF-8; format=flowed

Should the "RX ANT OUT" be terminated with 50/75ohms.

When only using the "RX ANT IN" BNC?

Rich

K3RWN

------------------------------

Message: 3
Date: Fri, 30 May 2025 14:04:01 -0700
From: Jim Brown <jim at audiosystemsgroup.com>
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3 RX Antenna OUT termination
Message-ID:
	<1a26c4c6-e8e5-4a9f-b5e0-90159731f4a9 at audiosystemsgroup.com>
Content-Type: text/plain; charset=UTF-8; format=flowed

On 5/30/2025 1:58 PM, Rich via Elecraft wrote:
> Should the "RX ANT OUT" be terminated with 50/75ohms.

There's no good reason for doing so.

73, Jim K9YC

------------------------------

Message: 4
Date: Fri, 30 May 2025 17:12:25 -0400
From: Rich <rwnewbould at comcast.net>
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3 RX Antenna OUT termination
Message-ID: <83264839-630f-4f3f-92b2-a39c520b3ca7 at comcast.net>
Content-Type: text/plain; charset=UTF-8; format=flowed

Thanks, I have not done so for the last decade either, but over heard a
discussion at Dayton so I was curious

Rich

On 5/30/2025 5:04 PM, Jim Brown wrote:
> On 5/30/2025 1:58 PM, Rich via Elecraft wrote:
>> Should the "RX ANT OUT" be terminated with 50/75ohms.
>
> There's no good reason for doing so.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> rwnewbould at comcast.net

------------------------------

Message: 5
Date: Fri, 30 May 2025 16:56:18 -0500
From: Ted Edwards W3TB <w3tb.ted at gmail.com>
To: Rich <rwnewbould at comcast.net>
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] K3 RX Antenna OUT termination
Message-ID:
	<CAGhFmTj-gL7AiJoaW1Rfg4__URz+1JRU1sV3EZUv6eGTWOX4Jw at mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"

Has anyone tried terminating like that?

73 de Ted Edwards, W3TB and G?PWW

and thinking about operating CW:
"Do today what others won't,
so you can do tomorrow what others can't."

On Fri, May 30, 2025 at 16:13 Rich via Elecraft <elecraft at mailman.qth.net>
wrote:

> Thanks, I have not done so for the last decade either, but over heard 
> a discussion at Dayton so I was curious
>
> Rich
>
> On 5/30/2025 5:04 PM, Jim Brown wrote:
> > On 5/30/2025 1:58 PM, Rich via Elecraft wrote:
> >> Should the "RX ANT OUT" be terminated with 50/75ohms.
> >
> > There's no good reason for doing so.
> >
> > 73, Jim K9YC
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Elecraft at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net Please help support this 
> > email list: http://www.qsl.net/donate.html Message delivered to 
> > rwnewbould at comcast.net
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> w3tb.ted at gmail.com
>

------------------------------

_______________________________________________
Elecraft mailing list
Post to: Elecraft at mailman.qth.net
http://mailman.qth.net/mailman/listinfo/elecraft
You must be a subscriber to post.
Elecraft web page: http://www.elecraft.com

End of Elecraft Digest, Vol 253, Issue 31
*****************************************