[Elecraft] Tuner losses

[Andrew Catanzaro]

Bill,

I am using an LDG 4:1 balun between the KAT100 and the 
450 ohm line that feeds my loop on 40 through 10 meters.
It's very similar to the Elecraft 4:1 balun.
On 80 and 160, because the conjugate impedance is low,
I use a 1:1 balun.  I bought it as a kit from Coil Winding Specialists.
I would have bought the 4:1 balun from Elecraft, but at the time I
first hooked this up, they didn't offer one.

With the vertical, I hook the output of the KAT100 to the 1:1
balun via a couple feet of coax.  Then I have about 25 feet
of 300 ohm ladder line from the output of the balun
to the base of the vertical.  One side of the
300 ohm line is connected to the radials and the other to the
vertical element.

I also have huge 4:1 and 1:1 baluns from CWS.  They are
rated at 10 KW.  I'm not sure how they came up with that
spec, but the ferrite cores are huge and the wire is heavy gauge.
There are big ceramic standoffs for the ladder line.  At
the 100 watt level, these don't offer any advantage over 
their smaller counterparts. 

Calculating true tuner efficiency is complicated as a load
that represents an SWR of 8:1 may be composed of all
radiation resistance and no reactance, as in a resonant,
short antenna, or it may be a 50 ohm antenna with a lot
of reactance that's being operated way off its resonant 
frequency.  That's why these discussions of tuner efficiency
never end.  Some tuners are better with different kinds
of mismatches.  Anyway, I've had great success with
the KAT100 into my particular loads, and I like that 
it doesn't stop tuning till the SWR is at, or very close to
1:1.  And most of all, I like the good current measurements
I get.  After all that, the QSO's just flow.

Let me know if you have any other questions.

73,
Andy


----- Original Message ----- 
From: "Bill Strong" <billstrong50 at yahoo.com>
To: <acatan at wi.rr.com>
Sent: Saturday, May 14, 2005 9:50 AM
Subject: Re: [Elecraft] Tuner losses


> Hi Andy,
> 
> I tried to post the message below after reading your very interesting
> comments. I don't think I did it correctly so I am emailing directly
> too.
> 
> Thanks,
> Bill WA5KPE
> 
> 
> I use an SGC 211 which sits on my desk beside my K2/100. It feeds 450
> ohm ladder line directly to my Cobra Ultralite 140' doublet. This works
> well enough except that the 211 will constantly retune if not disabled
> by turning it off. I also own the MFJ 974H balanced tuner. The 211 gets
> better matches.
> 
> I have ordered the KAT100 and the BL1 4:1 balun which will be here in 3
> days. My question is what balun are you using between the KAT100 and
> your loop? Also, do I understand correctly that with your vertical you
> are using the balun between the K2 and the KAT100 or is the 1:1 balun
> between the KAT100 and the vertical?
> 
> Thanks,
> Bill Strong WA5KPE
> Hattiesburg, MS
> K2 #4454
> 
> --------------------------------------------
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> 
>