[Elecraft] OT a bit: K3 Ant Tuner

[Gmail - George]

-----Original Message----- 
From: Jack Brindle via Elecraft 

...

Now having said this, the ATU can also be bypassed in the K3, and that circuit may provide a proper 50 ohm source/load for the BPF. I would probably take this approach myself (and in fact do so in my station). The reason I take this approach is to avoid the small loss that the internal ATU presents. In contesting, every db matters.

Note that we are talking nits at this point. Unless the ATU was tuned for a load quite a bit off 50 ohms resistive, (quite possible), then retuning won’t make much difference. Perhaps the op had this situation, and thought it better to return the ATU than to bypass it, or he didn’t even think to bypass it. The point is, both methods will work, and I doubt he did anything wrong it performing the tune.


Jack,
If I'm not mistaken - the KAT3 is not able to be physically  bypassed in a K3 - don't know in a K3S; but I thought the KAT3A  did a physical bypass. 
My understanding is that when you bypass the ATU (KAT3), it is merely being set to a value that cancels the internal L & C of the board.
I would think a tune would not actually actually change much of anything; but leave it to someone to actually test the true output impedance in both.

73
George AI4VZ

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