[Elecraft] KAT500 observations

[Jim Sheldon]

Got the KAT500 this evening and it took about 15 minutes to get the book read and the required cables connected.  I did cheat a bit and had the short RF cable made up to go between the KPA500 output and the tuner's input.  I also had the 15 pin aux cable made up to go from the KAT500 to the amp.  

Included with the tuner is a KUSB cable to allow computer connection for updating the firmware and also a 3 foot RCA to RCA cable to use for the KEY line if using other than an Elecraft amp so that the tuner can interrupt the amp keying during tuning.

The tuner draws up to 1.5 amps so you can't connect it to the K3's aux power connecter even if you have done the higher current mod to enable running the P3/SVGA from the K3 and it specifically states not to do that in the manual.

My station is arranged with the K3 on the left, P3 in the middle and the KPA500 on the left so I placed the KAT500 on top of the P3, centering it with overlap to the K3 and KPA500.  This way it looks good and doesn't cover any vents at all.

Since I don't have a hand key connected to the K3, I put it in data mode and hit the XMIT button to produce a carrier for tune.  It inhibits the amplifier just like it's supposed to and once it finds a proper match, brings the amp right on line.  Depending on how far it had to hunt, initial tuning on each band/antenna combination took anywhere from 1 to 6 or 7 seconds, but even with some weird combinations (using the 160 meter 1/4 wave inverted L on 80 for instance, it did tune it over the entire 80/75 meter range (after I remembered to take the old manual Dentron tuner out of the line and connect the L directly to the KAT500 instead of trying to tune it on 80 with the Dentron in line and set for the low end of 160 -- This did rattle the KAT and caused it to go into fault mode as it should have done.  Thanks Wayne for making it relatively idiot proof.

I don't have a specific antenna for 12 meters, but the KAT will tune my 17 meter dipole and my Butternut HF2V vertical on 12 very nicely.  Actually, the Butternut has the 160 meter loading coil on it and the KAT will tune it over all of 160, 80/75, 40, 30, 20, 17, 15, 12, 10 and 6 meters.  It tunes my 3 element Cushcraft A3S over the entire range of 20, 15 and 10 meters (10 is cut for the CW end and the KPA500 didn't like it up in the higher SSB portion.  Now I can operate the entire band if I wish.

Having the extra antenna connections also finally allows me to connect my 6 meter beam to the amp easily and I now have 500 watts on 6 where before I had the 6 meter beam connected to the ANT2 connector on the K3 and could only run 100 watts unless I re-cabled things.  This may allow me to get through the KW curtain on the East Coast and work into EU next summer if 6 opens again.  I heard them this year, but couldn't bust through with only 100 watts and my 3 element beam @ 50 feet.

So far, it tunes all my antennas on their appropriate bands and even on some they weren't designed for as well.  I haven't found a frequency where I couldn't get it to achieve a 1:1 match using antennas that the K3's internal tuner will also achieve 1:1 on.  

All in all, it's been well worth the wait and a welcome addition to the shack here and now for the QRP stuff, my KX3 kit is scheduled for delivery Monday!  


Jim - W0EB