[Elecraft] SWR

[Mike K2MK]

Hi Chris:

I have a K3 and a BigIR. The problem with using a tuner with any SteppIR
antenna is that you want want to change the SteppIR controller frequency to
match your transmitter frequency which then changes the length of the
antenna. As you know, this is how SteppIR maintains good SWR over the entire
band. This happens automatically if you have the transceiver tracking option
with your SteppIR. You do it manually if you don't have tracking So what
next, do you then activate the ATU tune function on the K3 to readjust the
internal tuner? It's just a little bit of additional complexity. This
procedure would be especially troublesome on 80 meters where the antenna
makes substantial length adjustments every 10KHz.

With the 80 meter coil option on the BigIR, you could see higher SWRs on 15
through 6 meters in the  normal 1/4 wave mode. SteppIR recommends using the
3/4 wave mode for those bands. This may help.

Before my K3, I had a FT1000D. I saw power rollbacks on 17 and 30 meters
where my BigIR SWR is 2.0:1 and 1.6:1 respectively. So I used the tuner on
those bands. I don't see any power rollback with my K3 so I don't use the
tuner on those bands anymore.

73,
Mike K2MK



Chris Hembree wrote:
> 
> When do you know if you need an ATU (KAT3). I just installed my  Big
> SteppIR Vert.
> On 6m my swr is 1.9, 17m,20m,80m a swr of 1.6.
> Thanks
> Chris W7CTH
> 
> 
> 
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