[Elecraft] AX1 works great

[David Gilbert]

Congratulations on your results with the AX1, but if you don't think 
that the internal matching unit doesn't tune your antenna then you don't 
understand how impedance transformations and transmission lines work.

Look at it this way.  In a simple example, you could add a coil to a 
short dipole to tune it to resonance.  Or you could put an appropriate 
impedance at the near end of a transmission line such that at the far 
end (after the transformation performed by the transmission line) it had 
an inductance of the same value as the coil ... which is exactly what 
the matching unit in the rig does.

I could literally connect two transmission lines to the antenna 
feedpoint ... one that went directly to the rig and another in parallel 
that went to a matching unit.  The one that went to the matching unit 
would tune the antenna to resonance (let's ignore whether it results in 
a 1:1 SWR for the moment) and the net result would act identically to an 
antenna that was natively tuned to resonance.

I've never understood why people try to make that comment about a tuner 
in the rig not actually tuning the antenna.  Makes no sense to me, and 
it seems to be some sort of ill informed distinction that took on a life 
of its own.  "Matching unit" is certainly a better description, but in 
its own way a matching unit does indeed tune the antenna.

That being said, resonance doesn't necessarily equate to being matched, 
of course.

Dave   AB7E



On 9/28/2024 11:19 AM, Kitchens, John, NS6X (SM, SB) via Elecraft wrote:
> Performance for me has nothing to do with SWR, but am I making QSOs. I do. With the AX1 attached directly to the radio, KX2 and KX3, using the internal matching unit ("tuner", which has little to do with tuning the antenna), I have made 68 activations, 10-40 meters cw. From California, I have worked into China and asiatic Russia on 17 meters.
> The silly thing works, and works well. Propagation must be in your favor. It has not worked every day. I have had to resort to digital modes occasionally to complete an activation (add another 32 activations). It was my main radio system, along with a KH1 on my two recent trips, one a three month cross country pota trip.
> The SWr was 1:1, usually, with the internal tuner. I always used the AX1 attached directly to the radio with a 3D printed antenna support.
>
> I have used other radios and antennas, usually when stopped for more than a few hours, but the AX1 and kx2 have allowed for me to make a quick stop, usually less than one-hour total, to activate parks. Again, direct connection to the radio, 40-15, modified AX2 for 10, internal tuner, one radial as supplied by elecraft.
> Don't overthink it. SWR does not equate to resonance. Remember tube radios-we had the SWr/tuner/matching device built into the radio, usually as a pi network.
>
> John
> NS6X
>
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