KAT500 band change fault

K0FG_Fred

Just hooked up my KAT500 and KPA500 to the 6400M. I only have one antenna, an OCF dipole and I went thru all the bands and trained the tuner. Often when I change bands the tuner does not change bands and load the stored memory, then the tuner goes into a fault condition. Reset the fault and tap the key a couple times and usually the tuner retunes and works ok. Sometimes it recalls the stored memory and other times it goes into a tuning cycle. Sometimes I must reset the fault on the tuner, push the tune button on the radio and then the tune button on the tuner and it does a full retune.

Having the amp online does not affect the operation of the tuner. And it does it on both SSB and CW.

I turned the amp on standby to watch the band display and every time I change bands it is correctly shown on the amp's display. But the tuner does not automagically get that band change data and recall the stored memory so when I push the key or ptt the tuner goes into fault. The amp sees the band changes immediately but the tuner does not.

Maybe a timing issue? Does the delay on TX1 affect data going to the tuner? Or is it only for the ptt line to the amp?

Fred, K0FG

KD0RC

Hi Fred, I have the KPA500/KAT500 in use with my Flex 6400. I don't see your issue when I operate here. How do you have the tuner connected to the Flex? Do you have both USB cables accounted for in the USB Cables set up screen?

I am currently using DDUtil here, so I have the tuner plugged into the PC and the amp with one connection to the Flex and one to the PC. That is why the top entry is greyed out. If I were to pull the cable out of the PC and plug it into the Flex, it would light up again.

K0FG_Fred

Hi Len... I have both USB cables connected to the 6400M as per the instructions that came from Elecraft when I ordered the cable kit.

Cannot get DDUtil to work, every time I start it the system refuses a connection. Went thru all the suggested fixes and it still does not connect. After doing a fix it connects one time. Close the program and open it and it refuses connection.

Fred, K0FG

KD0RC

So if you go to Settings, USB Cables in SmartSDR, do both cables show up?

if you select the tuner cable and click Edit, do you get something like this?

K0FG_Fred

Yes both usb cables show up, and do look like your example. They work correctly sometimes. This is all on one dipole and the tuner setttings have all been stored before.

Just tried it. Tune up on 1.800 ok. select 1.900 profile and hit key, works ok. select 3.550, does not work-tuned it. select 3.902 profile it works ok. Go back to 3.550 profile, works ok. Go back to 1.800 profile, does not work-tuned it. Go to 1.900 profile works ok. go to 3.556 profile, does not work.

Went to 10 meters and tuned. Went to 15 meters-ok. Went to 20 meters-ok. Went to 30meters-ok. Went to 40 meters - fault. Sometimes when I hit the key the tuner did a very brief retune, sometimes not.

When I say it works it may be that the tuning is close enough it does not go into fault, but it's not optimum tuning, as in recalling the stored memory. But going to a different, low band the tuning is so far apart, and the tuner is not getting the new band/freq data that it goes into fault before the band/freq data gets there.

Sure glad I have you smart guys helping me, otherwise I might still be looking for the power switch.

Fred, K0FG

KD0RC

When you change bands, do you hear the KAT500 relays clicking? If not, the KAT500 and Flex may not be talking. Try unplugging and re-plugging in the USB cable at both ends.

Another possibility is RF getting into things. If you do the same exercise using low power (say 10 watts or so), does everything behave normally?

K0FG_Fred

Hi Len.. Maybe you have it figured out. When I change bands at 10 watts it all works fine. Then at 20 watts it does not work. I did put ferrites on all the new cables I added. Both ends of the usb cables and the KAT end of the rca ptt wires. But at 20 watts it still does not work.

I'm changing from 160 meters to 20 meters. The tuner has memories at both freqs as indicated by the fact it works at 10 watts.

I put the tuner into auto mode and it does a full retune with each band change so it is seeing a high swr. In manual mode it just goes into fault mode no matter which direction I change bands.

I've been running this setup for years with the K3S, no problem, still using the same coax and coax switches, same power supply, same antenna. The I added a bunch of new wires into the mix. Do you think that going from 10 to 20 watts would completely wipe it out.

After I tune the tuner on a band I can run 500 watts and no effect on the tuner. But when I change bands and only xmit 20 watts the tuner goes crazy.

Of course if I run the internal tuner it works fine. It appears to be a good tuner as it tunes my OCF dipole on all bands very nicely.

Since I think it is rf related I will muck around a bit with it. Thanks for the help.

Fred, K0FG

K0FG_Fred

Think the problem is fixed after talking with K6XX from Elecraft support. In the tuner utility turn off the idle sleep setting. Evidently the Elecraft radios send a wake up signal to the KAT but the Flex does not. Seems to be working now.

Fred, K0FG