K3 and end fed wire


JOHN MCBRIDE
 

I am considering using my K3 on Field Day with an end fed wire. I have studied the information from Wayne N6KR as well as looked at other information on this topic on line. I am wondering about a transmission line from the ATU (RG8 or other) on the K3 to connect to the end fed wire several feet away. But the recommendation is for the counterpoise to be connected to the ground on the K3. Do I need to run a separate counterpoise wire from the K3 or can the counterpoise be connected to the braid/shield of the transmission line? Any and all responses will be helpful. Thanks!
--
John N0UQC


Mike Flowers
 

This article describes an antenna for use with the KX2/KX3, but of course would work with a K3:

 

https://reflector.sota.org.uk/t/simple-resonant-multiband-antenna-for-use-with-kx3-2-and-internal-atu/16978

 

- 73 and good DX de Mike, K6MKF, NCDXC Secretary

 

From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of JOHN MCBRIDE
Sent: Tuesday, May 18, 2021 09:11
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] K3 and end fed wire

 

I am considering using my K3 on Field Day with an end fed wire. I have studied the information from Wayne N6KR as well as looked at other information on this topic on line. I am wondering about a transmission line from the ATU (RG8 or other) on the K3 to connect to the end fed wire several feet away. But the recommendation is for the counterpoise to be connected to the ground on the K3. Do I need to run a separate counterpoise wire from the K3 or can the counterpoise be connected to the braid/shield of the transmission line? Any and all responses will be helpful. Thanks!
--
John N0UQC


Mel Farrer, K6KBE
 

John what bands are you wanting to operate?

My favorite end fed wire is the ECOCFD  End connected Off center fed dipole.  I have the construction article if you are interested.  Cheers,

Mel, K6KBE

On Tue, May 18, 2021 at 10:46 AM JOHN MCBRIDE <jlm124@...> wrote:
I am considering using my K3 on Field Day with an end fed wire. I have studied the information from Wayne N6KR as well as looked at other information on this topic on line. I am wondering about a transmission line from the ATU (RG8 or other) on the K3 to connect to the end fed wire several feet away. But the recommendation is for the counterpoise to be connected to the ground on the K3. Do I need to run a separate counterpoise wire from the K3 or can the counterpoise be connected to the braid/shield of the transmission line? Any and all responses will be helpful. Thanks!
--
John N0UQC


Dennis Moore
 

How are you transitioning from the coax to the end fed?

If the antenna is connected directly to the jack on the K3 then the counterpoise would be necessity be connected to the chassis at some point. But if you're running a length of coax out to the antenna and using some sort of unun, connect the counterpoise at that unun and use some type of choke on the coax to keep RF off the shield.

When I'm using an end-fed antenna placed away from the rig, I use the HF matchbox found here: http://www.earchi.org/proj_homebrew.html connected directly to an ugly balun. With this setup I've worked as far as Thailand, Spain, Fiji, New Zealand from California. Easily handles 100 watts.

73, Dennis NJ6G

On 5/18/2021 09:11, JOHN MCBRIDE wrote:
I am considering using my K3 on Field Day with an end fed wire. I have studied the information from Wayne N6KR as well as looked at other information on this topic on line. I am wondering about a transmission line from the ATU (RG8 or other) on the K3 to connect to the end fed wire several feet away. But the recommendation is for the counterpoise to be connected to the ground on the K3. Do I need to run a separate counterpoise wire from the K3 or can the counterpoise be connected to the braid/shield of the transmission line? Any and all responses will be helpful. Thanks!
--
John N0UQC


Mel Farrer, K6KBE
 

EVER Heard of the ECOCFD?  
Not my design, but it WORKS.

Mel, K6KBE

On Tue, May 18, 2021 at 11:09 AM Dennis Moore <dennis@...> wrote:
How are you transitioning from the coax to the end fed?

If the antenna is connected directly to the jack on the K3 then the
counterpoise would be necessity be connected to the chassis at some
point. But if you're running a length of coax out to the antenna and
using some sort of unun, connect the counterpoise at that unun and use
some type of choke on the coax to keep RF off the shield.

When I'm using an end-fed antenna placed away from the rig, I use the HF
matchbox found here: http://www.earchi.org/proj_homebrew.html connected
directly to an ugly balun. With this setup I've worked as far as
Thailand, Spain, Fiji, New Zealand from California. Easily handles 100
watts.

73, Dennis NJ6G

On 5/18/2021 09:11, JOHN MCBRIDE wrote:
> I am considering using my K3 on Field Day with an end fed wire. I have
> studied the information from Wayne N6KR as well as looked at other
> information on this topic on line. I am wondering about a transmission
> line from the ATU (RG8 or other) on the K3 to connect to the end fed
> wire several feet away. But the recommendation is for the counterpoise
> to be connected to the ground on the K3. Do I need to run a separate
> counterpoise wire from the K3 or can the counterpoise be connected to
> the braid/shield of the transmission line? Any and all responses will
> be helpful. Thanks!
> --
> John N0UQC






K9MA
 

I know they're not popular, but I recommend an external tuner located at the end of the wire. The only exception might be if the coax is short and the wire is NOT a multiple of a half wave. In either case, the counterpoise connects near the end of the antenna.  If you can, the simplest arrangement is to bring the end of the wire right to the tuner near the radio. 

That said, the half wave multiple wire can work very well, if you can match it with an external tuner. (Some use a 9:1 transformer, but I don't.) The big advantage is that only a minimal counterpoise is required, because the antenna impedance is very high. Also, the part of the wire near the feedpoint doesn't radiate much, so bringing the wire right to the radio doesn't hurt performance much.  I have long been using an end fed 40 meter half wave for portable operation on 40, 20, and 15 meters. For 80 meters, I add two 20 meter long radials, bypass the external tuner, and use the internal ATU. On 80, an isolation choke cuts down on RF in the shack, though I don't use it for QRP operation.

73,
Scott K9MA

On 5/18/2021 11:11 AM, JOHN MCBRIDE wrote:
I am considering using my K3 on Field Day with an end fed wire. I have studied the information from Wayne N6KR as well as looked at other information on this topic on line. I am wondering about a transmission line from the ATU (RG8 or other) on the K3 to connect to the end fed wire several feet away. But the recommendation is for the counterpoise to be connected to the ground on the K3. Do I need to run a separate counterpoise wire from the K3 or can the counterpoise be connected to the braid/shield of the transmission line? Any and all responses will be helpful. Thanks!
--
John N0UQC


-- 
Scott  K9MA

k9ma@...


Michael Kopec
 

I know I will probably get a lot of what the heck feedback on this set-up, but it works for me using both my kX3 and K2 with internal tuners, I use a bnc test connector with two test poles connected directly to the radio. I directly connect a 27ft wire, usually strung at a 30 to 45 degree upward angle, to the red pole and a 27ft counterpoise/radial to the other black pole, usually laid on the ground. The xcvr tunes fine on 10 thru 40m with the internal tuner. When I am done operating, I just roll up the #20 stranded wire on a old fishing line spool. It is easy and works for me.

On Tuesday, May 18, 2021, 04:42:51 PM EDT, K9MA <k9ma@...> wrote:


I know they're not popular, but I recommend an external tuner located at the end of the wire. The only exception might be if the coax is short and the wire is NOT a multiple of a half wave. In either case, the counterpoise connects near the end of the antenna.  If you can, the simplest arrangement is to bring the end of the wire right to the tuner near the radio. 

That said, the half wave multiple wire can work very well, if you can match it with an external tuner. (Some use a 9:1 transformer, but I don't.) The big advantage is that only a minimal counterpoise is required, because the antenna impedance is very high. Also, the part of the wire near the feedpoint doesn't radiate much, so bringing the wire right to the radio doesn't hurt performance much.  I have long been using an end fed 40 meter half wave for portable operation on 40, 20, and 15 meters. For 80 meters, I add two 20 meter long radials, bypass the external tuner, and use the internal ATU. On 80, an isolation choke cuts down on RF in the shack, though I don't use it for QRP operation.

73,
Scott K9MA

On 5/18/2021 11:11 AM, JOHN MCBRIDE wrote:
I am considering using my K3 on Field Day with an end fed wire. I have studied the information from Wayne N6KR as well as looked at other information on this topic on line. I am wondering about a transmission line from the ATU (RG8 or other) on the K3 to connect to the end fed wire several feet away. But the recommendation is for the counterpoise to be connected to the ground on the K3. Do I need to run a separate counterpoise wire from the K3 or can the counterpoise be connected to the braid/shield of the transmission line? Any and all responses will be helpful. Thanks!
--
John N0UQC


-- Scott  K9MAk9ma@...


JOHN MCBRIDE
 

Thanks for the responses. For clarification I can get by with an antenna that will work 10m-40m.  Unfortunately the place I will be setting up the radio and antenna has few trees which limits the options, especially the length of the antenna. Why? The priority for this Field Day site is to be an accessible public location that hopefully many people will visit and be encouraged to become amateur radio operators.

All of the antenna suggestions will be considered, if not for this coming Field Day then later on.

FYI I live in an HOA and my antenna is a vertical wire cut for 20 meters and in a tree, with 16 ground stapled radials. I have a great SWR from 40m to 15m. So, I am confident I can find an antenna that will work for Field Day. And at my QTH I like to use the K3 for PSK31 at 30 Watts.

John N0UQC

--
John N0UQC


Jim Brown
 

On 5/18/2021 1:42 PM, K9MA wrote:
I know they're not popular, but I recommend an external tuner located at the end of the wire. The only exception might be if the coax is short and the wire is NOT a multiple of a half wave. I
Um, he said he was running a few feet of coax.

I don't see the need for coax unless it is used to insert a common mode choke, but I DO see the STRONG need for a counterpoise. That can be anything from radials to one or more wires placed where you can. In general, more and longer is better. They should be connected to the radio's chassis.

BTW -- this is antenna fundamentals, has NOTHING to do with the radio, except that a tuner may be required to match it.

A convenient way to do this is with a BNC to Pomona adapter -- that is, BNC to a red/black pair of female bananas jacks. Pomona part #1296. Google "pomona 1296" to see a photo.

73, Jim K9YC


Mel Farrer, K6KBE
 

Jim, you and I have had this discussion several times, I prefer an antenna that does not need a ground counterpoise and a tuner for most bands, sorry.  END.

Mel, K6KBE

On Tue, May 18, 2021 at 3:34 PM Jim Brown <k9yc@...> wrote:
On 5/18/2021 1:42 PM, K9MA wrote:
> I know they're not popular, but I recommend an external tuner located at
> the end of the wire. The only exception might be if the coax is short
> and the wire is NOT a multiple of a half wave. I

Um, he said he was running a few feet of coax.

I don't see the need for coax unless it is used to insert a common mode
choke, but I DO see the STRONG need for a counterpoise. That can be
anything from radials to one or more wires placed where you can. In
general, more and longer is better. They should be connected to the
radio's chassis.

BTW -- this is antenna fundamentals, has NOTHING to do with the radio,
except that a tuner may be required to match it.

A convenient way to do this is with a BNC to Pomona adapter -- that is,
BNC to a red/black pair of female bananas jacks. Pomona part #1296.
Google "pomona 1296" to see a photo.

73, Jim K9YC