[Elecraft] Antenna Tuner Or Not

[Mike Morrow]

>> So, are there advantages to the internal KX3 ATU over the T1.


> I believe the tuning range on the internal ATU is very wide.  Someone
> on the reflector compared the tuning ranges of all the Elecraft ATUs
> and it is wider than the T1.

I posted such information last month, summarized now as follows:

ELECRAFT ATU L AND C CONFIGURATIONS

The reactance configuration for all Elecraft ATUs is an L-network of series
inductance, with a capacitance connected to common before (radio side) or
after (antenna side) the inductance (but not both) by a relay.  It is a
classic low pass filter.

KAT1, Configs=1020, L=0 to 4.9 uH (16 steps), C=0 to 300 pF (32 steps)

KAT2, Configs=131068, L=0 to 20.7 uH (256 steps), C=0 to 2420 pF (256 steps)

KAT3, Configs=131068, L=0 to 17.4 uH (256 steps), C=0 to 2600 pF (256 steps)

KXAT1, Configs=124, L=0 to 4.5 uH (8 steps), C=0 to 140 pF (8 steps)

KXAT3, Configs=131068, L=0 to 15.9 uH (256 steps), C=0 to 2680 pF (256 steps) 

T1, Configs=32764, L=0 to 7.5 uH (128 steps), C=0 to 1300 pF (128 steps)

The last two entries show a significantly greater range of reactance that
the KXAT3 can insert...double the inductance and the capacitance of the T1.

It *always* surprises me though, that in Elecraft-world all manner of antenna
deformity is to be handled by an ATU magic bullet.  Small-conductor ATUs are
never your friend, if an antenna/feedline could be used that doesn't require
tuner reactance.  TANSTAAFL!

73,
Mike / KK5F