[Elecraft] KAT500 apparent loss of control

[Robert G Strickland]

Dick...
All the problem data occurs when running 25-30w from the K3 just for 
purposes of configuring the KAT500. There's no high power involved. I 
just measured the antenna again as follows:

test setup: MFJ 259B thru 1:1.5 Amidon UNUN to coax feedline
antenna: 40m sloping dipole, center fed, 55ft to 8ft, about 45deg slope
feed line: RG59, just about 1/2 electrical wave length long at resonance
resonance: 7013 MHz [all cw, here]
impedance: R56 J9
vector impedance: 57ohm at 20deg
VSWR: 1.2

Note, in operation, the coax is connect directly to the KAT500; the UNUN 
is not used.

I've got the Fault Table, but can't figure out how to export it. 
Directions? Thanks again.

...robert



On 9/6/2013 14:48, Dick Dievendorff wrote:
> The ATU goes into bypass if too much RF power is applied into a high SWR
> antenna (as measured by the "bypass VSWR".  The tuner is rated for an
> antenna load (as measured by the Bypass VSWR) of 10:1 SWR at 600 watts and
> 3:1 SWR at 1500 watts. If you exceed these limits, the tuner will go into
> bypass and signal a fault.  The KAT500 Utility display of the fault log may
> be of interest.
>
> Did your antenna change?  Still using the right antenna connectors for the
> antennas you do have?
>
> Try tuning with relatively low power, under 200 watts, to see if it goes
> into bypass at low power. If it doesn't, and does go into bypass as you
> increase power, and the bypass VSWR is higher than 3:1, then that may be the
> issue.
>
> 73 de Dick, K6KR
>
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Robert G Strickland
> Sent: Thursday, September 05, 2013 19:50 PM
> To: Elecraft
> Subject: [Elecraft] KAT500 apparent loss of control
>
> My KAT500 is running the latest firmware, 1.32, which I loaded a few weeks
> ago. For the past year or so of operation it has worked flawlessly. Now, not
> sure why, I am encountering various anomalies.
> Using the tuner utility (v 1.13.5.12):
>
> - I cannot manually adjust the tuning (for better or worse); the utility
> keeps reverting to "BYPASSED," and the VSWR and Bypass VSWR are the same;
> there are no checked boxes for L/C.
>
> - In Auto mode, much the same. Key the K3 and initiate tune; KAT500 tunes to
> a not-so-low VSWR; the utility operate window reverts to "BYPASSED," no L/C
> boxes checked, and bypassed and tuned VSWR are the same (high).
>
> - Loaded factory defaults and tried as above with no change.
>
> - I notice with K3 off and watching the config utility, the "bypass" box
> always reverts to BYPASSED; I can un-check it, and in about 2sec it reverts
> to BYPASSED.
>
> Note, I have adjusted the VSWR thresholds to Autotune at 1.5 and Bypass at
> 1.2. However, the autotune function always reverts to BYPASS with the high
> VSWR (on a resonant antenna as indicated on a MFJ259B). Also, the TUNE STATE
> indicates 0 6 199 (?). Thus, I have limited to no control over operation,
> the unit keeps reverting to bypassed, and the resultant VSWR is higher than
> without the tuner. Any help on how to work with this or what may be
> happening is appreciated. Thanks ...robert
> --
> Robert G Strickland, PhD ABPH - KE2WY
> rcrgs at verizon.net.usa
> Syracuse, New York, USA
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-- 
Robert G Strickland, PhD ABPH - KE2WY
rcrgs at verizon.net.usa
Syracuse, New York, USA