I'm glad you found the cause and a fix.
I'll add that, in my experience, 40M is always the most problematic band
for causing RFI problems. In a vehicle or home, it seems that a LOT of
'stuff' is sensitive to 40M. 160M comes in second for that status.
73,
Rick nk7i
On 11/21/2023 2:55 PM,
"I should be able to fix the problem with better decoupling and/or choking of
the breakout box connections."
Problem fixed by adding a 0.01 disc ceramic caps on each of the 4 RCA keyline
jacks on the breakout box. I should have included them when I built it.
Interesting problem though and all
On 11/21/2023 9:03 AM, Andy Durbin wrote:
I should be able to fix the problem with better decoupling and/or choking of
the breakout box connections.
That suggests bonding and grounding may not be sufficient. Every chassis
that is part of the station must be bonded together, and that bonded
Hi Clay:
I concur with your comments re cheap connectors. I have had cheap connectors
melt, short, go open and mechanically come apart. Fortunately these were in
the days of big old tube-based robust rigs.
I gave up on bargain connectors about 35 years ago. I’m happy to pay
substantially
I followed up on the RFI theory and quickly found a solution to the problem.
My TS-590S has a homebrew breakout box on the REMOTE connector. This breakout
box provides key line level shift and key line interrupt for my SteppIR. The
TS-590S ALC control line is on this cable but is not
NOT directly related, and MAY not be related AT ALL but consider
clearing the tuning solutions stored on a section of the band where it
oscillates and let it RE-tune at a power level JUST below what it was
oscillating at
Then turn her up and see if it still does it. Likely will, but
Listen to Jim, guys. THE most frustrating thing in troubleshooting is
when the "trouble" is in the cheap/low quality parts used in an assembly.|
ALWAYS buy the best you can find/afford. Buy the best; buy once. I have
a FEW more vendors than Jim, but his point is nonetheless valid and
should
Is the internal autotuner of the TS590S on?
- Jerry
On 2023-11-21 04:50, Andy Durbin wrote:
Thanks to those that replied with suggestions.
This morning I ran some additional testing. I found I could induce
the oscillation at 70 W KPA500 output power. With KPA500 switched to
STBY I
I found that the power for onset of oscillation is strongly dependent on
frequency:
7.01 C0,L0, SIDE T - max no osc 108 W
7.02 C0, L710, SIDE T - max no osc 118 W
7.03 C0, L710, SIDE T - max no osc 129 W
7.10 C0, L710, SIDE T - max no osc 222 W
7.20 C47, L820, SIDE T - max no osc unknown
"Perhaps check and see if the drive from the TS-590s is varying, or if the gain
of the KPA500 is changing. What does the output meter on the 590 say when this
happens?"
TS-590S power meter does not change nor does TS-590S indicated SWR. However, I
did find that TS-590S ALC reading is cycling.
Perhaps check and see if the drive from the TS-590s is varying, or if
the gain of the KPA500 is changing. What does the output meter on the
590 say when this happens?
73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/
On 21/11/2023 14:50, Andy Durbin wrote:
Thanks to those that replied with suggestions.
This morning I ran some additional testing. I found I could induce the
oscillation at 70 W KPA500 output power. With KPA500 switched to STBY I could
run 100 W from my TS-590S with no anomalies. The only change in the antenna
system
On 11/20/2023 8:00 PM, Rick NK7I wrote:
In that search, high on the list of suspects (right up there with
failure of any antenna elements) is damage from tiny livestock (mice,
rats, birds that may have gotten into the attic or bugs like mud wasps);
chewed wires, cables and insulators.
More
Andy,
You've answered your own question. If it doesn't happen when the entire
rig system transmits into a dummy load, but has problems while connected
to an antenna; you know where to look.
In that search, high on the list of suspects (right up there with
failure of any antenna elements)
This is really strange.The only thing I can think of is some kind of
feedback to the TS-590s ALC circuitry caused by common mode current on
the feedline. An easy test would be to connect a common mode choke at
the output of the KAT500 and see if the problem goes away. Does the
antenna have
I have a new power oscillation problem that is manifest only on 40 m when using
an attic dipole. Basic station configuration is Kenwood TS-590S, KAT500,
KPA500. As drive power is slowly increased and output power rises above about
100 W the power output falls to zero then slowly rises again.
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