Elecraft K3 – Line Out TX Monitor

Dec 2022 / Jan 2023 —

I have been trying to setup up the K3 and Mumble to enable proper audio for remote operation.  The issue encountered was at the remote location, microphone input was being played back into my ears with the round trip induced latency, essentially “jamming” my ability to speak coherently.

Thanks to an email with the exact solution from Kazu M0CFW, M5Z, JK3GAD, I have figured it out!  K3 LIN OUT has a TX MON setting that was added later than my printed user manuals (K3 # 251, so it has been around a while).

K3 MCU 5.58 / DSP 2.88 / FPF 1.26, 3-16-2017

* PREAMP 2 (ON KXV3B) NOW USABLE ON 15 AND 17 M: PREAMP 2 improves noise figure by about 6 dB on 15 m and 3 dB on 17 m relative to PREAMP 1.

* TX LINE OUT (MONITOR) LEVEL NOW ADJUSTABLE: In CONFIG:LIN OUT menu entry, tap ‘2’  (REV switch) to set the “T=” level (TX monitor). Tap ‘2’ again to return to the RX LINE OUT setting

K3 documentation and software update

All three of my K3 had TX MON = 30.  Adjust to 0, Mumble problem 100% resolved!

I remember now that this was set to provide ability to record N1MM voice keyer messages on the fly! Because I didn’t remember, I’ve made notes in the config matrix of all my K3 manuals.

–Scott, W5WZ

2022-Feb NAQP RTTY

2/27/2022 @W5WZ – M/2, ops W5WZ, WM5H, KD5YS

We played well together and in the contest, with an apparrent 4th place finish.

During NAQP RTTY, SWR and RF PWR bargraph seemed weird. High SWR, low RF output. RF power set to 100 watts. Outboard LP-100A power meter showing SWR in normal range and power in normal range. As contest progressed, we noticed zero bars on SWR meter, and a single bar on RF meter. LP-100A was showing 100-126 watts, with normal SWR. After contest, connected a dummy load to the K3 Ant2 (easiest to do; normal antenna connected to Ant1) and the meter behaved the same. It was midnight, so didn’t do any other troubleshooting.

Within a day or two, got a support ticket open with Elecraft.