[Elecraft] Antenna Tuner and Balun comparison question

[Charles Greene]

David,

On the antenna tuner, I am using two K2's, 462 is the QRP version and it 
has the KAT2 option.  The other is 3571 with the 100 watt amplifier, and I 
am using a LDG Z11 antenna tuner with it.  I have used the Z11 at 100 watts 
for over a year now with no problems, although LDG rates it at 60 
watts.  It is a nice little antenna tuner and it performs 
flawlessly.  However, I miss the memory feature of the KAT2.  When 
selecting a band and an antenna, the KAT2 has 2 antenna connections, the 
KAT2 remembers what the tuning was and goes to it when the band and that 
antenna is selected.  The performance of the KAT100 antenna is similar as 
far as I know; I have never operated one. I know it  has a built in SWR 
indicator.  On the Z11 every time I change bands I have to retune.  I also 
miss having two antennas.  When I want to use a second antenna on the Z11, 
I have to change the coax connector.

I have an LDG remote antenna tuner in my sailboat.  It is mounted aft and 
feeds an insulated back stay.  If you want a remote tuner, the LDG remote 
tuner model RT-11 is the way to go.

Both the LDG and Elecraft tuners are L type tuners.  Although I have not 
tested either in any great detail, both do an equally good job of tuning an 
antenna in about the same length of time.  The LDG has an automatic mode of 
operation which the KAT2 does not have.  I have actually used mine as a 
remote tuner.  I mounted it in the trunk of my car and put it in Automatic, 
and when I wanted to retune my mobile antenna a little because I moved up 
or down the band, I just transmitted a carrier, and it quickly tuned the 
antenna to 1:1 SWR.  It has manual switches for capacitance and inductance 
up or down, in case you can't get a match using the tune button.  It has 
LEDs which indicate SWR <1.5, 2.0 and >3.0

On the balun, the LDG balun is a voltage balun and the Elecraft balun is a 
current balun.  A current balun is generally preferred over the voltage 
balun.  It has a wider frequency range, as the voltage balun performance 
falls off at higher frequencies.  Also, the current balun can transform a 
wider impedance range.  It can operate satisfactorily into a higher SWR 
than the voltage balun.  The voltage balun is simpler and needs only one 
core.  The current balun can be built with one or two cores.  In the case 
of the Elecraft balun, it has a single core.  I measured the frequency 
response of a single core of a two core current balun I designed, but wired 
it up as a voltage balun.  As a current balun, its frequency response was 
700 KHz to 35 MHz; as a voltage balun, it was 700 KHz to about 19 
MHz.  This is my design, and I don't know what the frequency response of 
the LDG balun is but I assume it performs satisfactorily over the entire HF 
range.  The specs on the Elecraft balun are 500 KHz through 55 MHz, I seem 
to remember.  The bottom line is that the Elecraft balun uses a different 
technology, and not to disparage the LDG balun, the Elecraft balun is bound 
to outperform the LDG balun in most applications hams will use it for.

On the other hand, Jerry Sevick, W2FMI, who wrote two books on baluns, 
prefers a voltage balun over a current balun for use in an antenna tuner, 
provided it uses a very large core of the proper material.

At 05:38 PM 10/17/2003, David Toepfer wrote:
>I have been trying to decide which tuner's I should consider using for the K2
>in my future.  I have always been impressed by the LDG tuners.  But it seems
>that the Elecraft tuners are at least as good (if not better as I expect) in
>design and have the bonus of being internal (integrated with a/b swithc and
>band memory) as well.
>
>I tried to compare specs, but the lit for the Elecraft tuners seem to be lean
>on basic inductance/capacitance specs from what I can find on the web site 
>(not
>sure why).  I suspect they are both Z-match tuners (less lossy than a T-match
>from what I understand) and are quite capable of tuning a wide array of 
>antenna
>mismatches.
>
>I guess what I am looking for is whether anyone has any experience with or
>knows of any comparisons (in addition to eham.net) of any of these tuners that
>might sway my decision one way or another on these 2 tuner comparisons:
>
>1)
>Elecraft KAT100 (http://elecraft.com/kat100/kat100_page.htm)
>vs
>LDG Electronics AT-11MP (http://ldgelectronics.com/at-11mp_description.html)
>
>2)
>Elecraft KAT2 (http://elecraft.com/Apps/kat_pics.htm)
>vs
>LDG Electronics Z-11 (http://ldgelectronics.com/z-11.html)
>
> From what I can see of the specs published on the Elecraft balun kit it seems
>quite fine as well and I am likely to get it in favor of the LDG unit, though
>the differences seem less radical.
>
>3)
>Elecraft BL1 (http://elecraft.com/mini_module_kits/mini_modules.htm)
>vs
>LDG Electronics RBA-1 (http://ldgelectronics.com/ba-1.html)
>
>In the end I so like the product Elecraft is producing and what I guess I am
>looking for is whether there is a compelling reason to not buy their tuners
>over what I believe is the next best auto-tuners out there.
>
>Thanks.
>
>dt

73, Chas,  W1CG
K2 462b, 3571