Internal K3 SWR vs Extermal SWR Meter

[pastormg]

Good Morning, this is Mark Griffin and my call is KB3Z. I am having some real issues when it comes to getting a reliable SWR reading between my K3 and an external Wavenode Meter. I hooked up my hexbeam directly to the input Antenna 1 Connector of my K3 and got the following SWR readings in the SSB portion of the band.

20 Meters:1.1
17 Meters: 1.1
15 Meters: 1.8
12 Meters 2.7
10 Meters:1.4

Yes, I know that 12 meters is high for some reason! But I than hooked up my antenna to the Wavenode coupler and then to the my Antenna 1 connector and notice the differences between the K3 and the Wavenode.

                  K3                                  Wavenode
20 Meters 1.1                                    1.6
17 Meters 1.1                                    1.4
15 Meters 1.8                                    2.3
12 Meters 2.7                                    1.9
10 Meters 1.4                                    1.7

Is anyone else out there experiencing the same issues between their K3 SWR and an external meter? Perhaps the wavenode coupler isn't good but I am so confused that I don't know what to do. Any assistance would be much appreciated.  Mark Griffin, KB3Z

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[W4JBB]

Mark,

You will get lots of responses to this. 99.9% of the folks on the
Elecraft are more experienced and smarter than me.

I have a similar situation with a WM-2 wattmeter and my KX3. Here's how
I stopped worrying about it:

1. I realized that I have to bypass the ATU in the KX3 to get a "good"
reading on the WM-2.
2. Even after doing #1, I still have a 2W discrepancy between the KX3
and the WM-2 (i.e. 5 W on the KX3 reads as 7 W on the WM-2). It varies
at different bands and output power.
3. In my experience, wattmeters vary greatly and there is a deviation
percentage that I think must be taken into account. I don't know what
that amount is either. :)
4. When I use one, I am looking at an external wattmeter with a needle
to get an instantaneous reading on reflected power. The needle is large
and visible and I keep the meter in REV when I use it. This leads to an
experience I had several years ago in a class on SCADA radios. The
discussion of the Bird 43 wattmeter came up:

I was once told that a Bird 43 wattmeter has about a 10 - 20% error rate
(I forget the exact number). I told the guy I didn't care as long as it
was the same inaccuracy when looking in both directions. I was looking
for a *ratio*, not necessarily an output power. He looked at me like I
was purple and had three eyes.

I try to simplify things. The purists and the engineers out there will
in all likelihood disagree with what I've said. I am sure there are
instances where what I say will not or cannot work. In my casual
operation as an amateur for 20 years, this has worked for me. In my
professional career as a telecomm tech doing PMs and trouble-shooting on
37, 450, and 900 MHz radios for almost as long, this has worked.

As with anything else I may say, this is just my experience. Your
mileage may vary greatly...

73,
Joel - W4JBB

On 11/17/13, 11:01 AM, [hidden email] wrote:

> Good Morning, this is Mark Griffin and my call is KB3Z. I am having some real issues when it comes to getting a reliable SWR reading between my K3 and an external Wavenode Meter. I hooked up my hexbeam directly to the input Antenna 1 Connector of my K3 and got the following SWR readings in the SSB portion of the band.
>
> 20 Meters:1.1
> 17 Meters: 1.1
> 15 Meters: 1.8
> 12 Meters 2.7
> 10 Meters:1.4
>
> Yes, I know that 12 meters is high for some reason! But I than hooked up my antenna to the Wavenode coupler and then to the my Antenna 1 connector and notice the differences between the K3 and the Wavenode.
>
>                    K3                                  Wavenode
> 20 Meters 1.1                                    1.6
> 17 Meters 1.1                                    1.4
> 15 Meters 1.8                                    2.3
> 12 Meters 2.7                                    1.9
> 10 Meters 1.4                                    1.7
>
> Is anyone else out there experiencing the same issues between their K3 SWR and an external meter? Perhaps the wavenode coupler isn't good but I am so confused that I don't know what to do. Any assistance would be much appreciated.  Mark Griffin, KB3Z
>
> ______________________________________________________________
> 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
>

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[John Oppenheimer]

A better way is to connect a load with a known SWR.

Using a "BNC-BP BNC Male to Stackable Binding Posts" with three 100 Ohm
1W resistors in parallel, 33.3 Ohms, SWR should ~= 1.5.

Directly connected to the K3, ATU in bypass, 5W output, measured SWR = 1.1.

18" piece of coax with W1 Power meter, same 33.3 ohm load, K3 SWR=1.1,
W1 SWR=1.4 (Using W1 utility)

My K3 is indicating a Low SWR at 5W output.

John KN5L
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