In his comment here /g/la1k/message/1258 on my post /g/la1k/message/1257 yesterday, with respect to the "Auto-Protect: SWR/Short Circuit/Over Temp" feature of the LA-1K, listed as part of its specifications on as of this writing, Paul NO0T writing, in part, "I didn’t notice I was getting too far from resonance and SWR went to 2:1, it went to bypass to protect the finals.? Just as designed - woohoo! Gotta love it - dummy proof."

Paul's excellent observations, as stated above, demonstrating yet another case of inferior design implementation found on the LA-1K amplifier, since an SWR as high as 2:1 is acceptable!

SWR reference material for all to consider:

73,
Ray
KJ5MI

开云体育

My SPE 1.5K-FA alarms at 1.7, and faults to standby at 2.1

My Elecraft KPA500 folds back to half-output at 2:1 and goes into the red zone (cautioned as "critical" in the manual) above 2:1.

My Yaesu Quadra required ATU action above 1.5.

73,
Kent
K9ZTV

My RF-Kit Goes into the orange at 1.6 and will kick out at 2.1.

On Thu, May 4, 2023 at 01:12 PM, Kent Trimble, K9ZTV wrote:

My Elecraft KPA500 folds back to half-output at 2:1 and goes into the red zone (cautioned as "critical" in the manual) above 2:1.

Hi Kent,

Where would one find the information, as stated above, in the KPA500 Owner's Manual: ?

73,
Ray
KJ5MI
PS - Elecraft Owner's Manual for the KPA1500 states the followings:

Page 18:

SWR bargraph: The SWR LEDs are green from 1 to 1.5. The 1.5 to 2 LEDs are yellow and the LEDs above 2 are red

Page 27:

The bargraphs are color-coded green for normal, yellow for marginal and red for excessive levels.
Excessive levels may trigger a fault and switch the KPA1500 to STBY