EXPERT 1K-FA — Web Console

A web replacement for Expert_Console2.exe, the Windows console for the SPE EXPERT 1K-FA linear amplifier — usable from a remote QTH. A small daemon owns the serial port and serves its own page; all protocol knowledge lives in index.html.

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Quick start

Install the only dependency (needed for live operation only):

apt install python3-serial

Try it without any hardware — the simulator answers keystrokes and streams plausible telemetry:

./expert_console.py --simulate

Then open http://127.0.0.1:8080/.

Run it against the amplifier:

./expert_console.py --port /dev/ttyUSB.pa --raw-port 7373 --listen 0.0.0.0

Press ON in the top row and wait roughly seven seconds — the amplifier raises DTR, boots, and the watchdog restarts the telemetry stream by itself.

Three things worth knowing before you start:

• Without --listen 0.0.0.0 the console is reachable only from the machine itself. This applies to --raw-port as well.
• The serial port is opened exclusively. If ser2net still holds it, the daemon says so instead of quietly fighting over the bytes.
• Nothing on screen? Open Diagnostics and read RX bytes — see Troubleshooting.

If the amplifier does not answer at all, this splits the problem into "is the port taken", "does DTR switch" and "does the amplifier reply":

sudo ./test/diag-serial.py /dev/ttyUSB.pa

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How it fits together

browser ──http──► expert_console.py ──► /dev/ttyUSB.pa ──► 1K-FA
                  (HTML + SSE + serial)      9600 8N1

The daemon is deliberately thin: serial port, DTR, HTTP, and passing bytes through. Framing, checksums, the 30-byte status record and the setup menus are all decoded in the browser.

Running the original Windows console under wine

expert-console.sh launches the original Expert_Console2.exe under wine. It serves as the reference implementation — useful whenever you are unsure whether the web console is reading something correctly.

./expert-console.sh                 # normal run
DEBUG=1 ./expert-console.sh         # plus a hex dump to /tmp/expert1k.log

The script bridges TCP to a PTY with socat, links it to COM1 inside wine and starts the application. It points at 192.168.1.201:7373, which is what our daemon's --raw-port 7373 serves — so it keeps working unchanged after you retire ser2net.

With DEBUG=1 you get paired ground truth: the bytes in the log, and the reference interpretation of those same bytes on screen. That is exactly how the decoder in this project was verified.

The script hard-codes EXE=/home/dan/inst/Expert_Console2.exe, and wine rewrites dosdevices/com1 on startup — hence the ordering inside: first wineserver -p, only then the symlink.

Why ser2net had to go

Because of DTR. ser2net raises it when a client connects and leaves it there, which controls the amplifier's power as a side effect you cannot steer.

DTR is a level switch, not an ignition pulse. Measured on the bench first:

1000 ms pulse, then DTR low  →  nothing for 45 s
DTR held high                →  reply after 6.7 s

Protocol Rev. 2.0 then confirmed it in as many words (p. 4): turning on is "simply raising it at a voltage level greater than +5 Vdc" and takes 3 to 4.5 seconds; turning off means "this control line has to be reset in its OFF state", about a second, because the state is sampled for at least 500 ms.

DTR high = amplifier running          DTR low = off

After power-up the amplifier resets RCU to OFF, so telemetry only resumes once the browser's watchdog sends RCU_ON again. It retries every 1.5 s, so waiting is enough.

The port is opened exclusively (TIOCEXCL). Without that, pyserial happily opens a port ser2net already holds; both then read from the same device and the incoming bytes are split between them at random — which looks exactly like "writes go out, nothing comes back".

If a different unit behaves the way Rev. 1.0 describes, use --dtr-mode pulse.

⚠️ Closing the port drops DTR, so restarting or crashing the daemon turns the amplifier off. That is the safe direction to fail in, but be aware of it when restarting during operation. --dtr-on-start brings it back up with the daemon.

Two protocol revisions

Both are supported and told apart by STATUS_CODE — there is nothing to configure, and the active revision is shown in Diagnostics.

	Rev. 1.0	Rev. 2.0
firmware	06_11_06_x	>= 07_07_07_M (Second Series)
STATUS_CODE	0x80	0xA0 / 0xA1 (bit 0 = startup mode)
FLAGS bit 7	PA_PROT	T_SCALE (1 = °C, 0 = °F)
CAT list	6 entries	+TEN-TEC, +FLEX-RADIO → RS-232 4→6, NONE 5→7
SETUP OPTIONS	0x07, 7 items	0x06, 9 items (+START, +TEMP.)
SET ANTENNA	0x08, 1 antenna/band	0x07, 2 antennas/band, index in SETUP_0
SET TEN-TEC	—	0x0B
antennas × bands	0x05	dropped (0x05 = DATA STORED!)

The whole DISPLAY_CTX map shifted by one from 0x05 upwards.

Controls

The top row shows state, not action — clicking toggles it. OPERATE and PWR-H are drawn inverted (filled), because those are the states in which the amplifier is actually working. Next to them sits the calculated SWR, visible only while transmitting and for a moment afterwards.

Button	Code		Button	Code
ON / OFF	DTR high / low		←L L→ ←C C→	0x30–0x33
STANDBY / OPERATE	0x1C		IN ←BAND BAND→	0x28–0x2A
PWR-L / PWR-H	0x1A		ANT CAT	0x2B, 0x2C
TUNE	0x34		← → SET	0x2D–0x2F
			DISPLAY	0x1B

Both revisions list 0x33 as L+, the same as 0x31. Going by the keyboard layout (0x32 is C-) it is really C+ — the error persists through both documents.

Bar graphs

Each bar is built from LED segments on a fixed 7 px pitch (5 px lit, 2 px gap). Narrowing the window reduces their number rather than their size, and the unlit segments stay visible so the full span is always readable.

• the number beside the bar shows the peak, refreshed slowly enough to be legible; the bar itself carries the instantaneous value
• FW, REV and I hold the maximum, V holds the minimum — with supply voltage the interesting figure is the sag under load, not the open-circuit reading
• a peak is drawn as a lit segment above the illuminated part, a dip as a bright notch inside it
• ranges follow the mode: FW is 1200 W in FULL, 600 W in HALF, and switches to the exciter range in STANDBY
• SWR is calculated from forward and reflected power — in OPERATE the amplifier does not send it, bytes 23–24 carry gain instead

Temperature is coloured by the fan switching thresholds (manual §18.17) and honours both CONTEST mode and the °F setting:

CONTEST off:  <40 grey · 40 green · 65 yellow · 75 sand · 90 red
CONTEST on:   first stage always running, second from 60, third from 70

Setup tree

The menu is a state machine inside the amplifier. There is no "set the antenna for 20 m to #2" command — only SET / ← / →, plus reading back where it currently is. So clicking a node cannot jump anywhere; it has to walk there, in a closed loop:

send ONE key → wait for the next STATUS packet to confirm → then the next

If the amplifier does not follow within a few attempts, the walk stops and says so. It never drums blind keystrokes into a kilowatt amplifier.

Where selecting an item is the value (SET CAT, SET YAESU/ICOM/TEN-TEC, SET BAUDRATE), that maps onto a drop-down: choose, then Apply. MANUAL TUNE and BACKLIGHT get +/− buttons, SET ANTENNA clickable bands.

The route into SET BAUDRATE is not documented in the specification, so the walker will not enter it — the manual arrows still work.

Losing the address bar and tabs

1. Application mode — works immediately, nothing to prepare:

google-chrome --app=http://192.168.1.201:8080/
firefox       --kiosk http://192.168.1.201:8080/

2. Full screen — F11.

3. Install as an app. The console serves manifest.webmanifest and an icon, but Chrome only offers installation over HTTPS or from localhost. Once Apache with a certificate sits in front of the daemon, it starts working on its own. On iOS, Share → Add to Home Screen works over plain HTTP too.

Deployment

[Service]
ExecStart=/opt/expert/expert_console.py --port /dev/ttyUSB.pa \
          --raw-port 7373 --listen 127.0.0.1 --http-port 8080
Restart=always
User=dan

Apache as a reverse proxy when you need HTTPS and a password from outside. SSE does not need mod_proxy_wstunnel:

<Location /expert>
  AuthType Basic
  AuthUserFile /etc/apache2/.htpasswd
  Require valid-user
  ProxyPass        http://127.0.0.1:8080/
  ProxyPassReverse http://127.0.0.1:8080/
  SetEnv proxy-sendchunked 1
</Location>

Migrating from ser2net

1. systemctl stop ser2net && systemctl disable ser2net
2. Start the daemon with --port and --raw-port 7373
3. expert-console.sh keeps working unchanged

Troubleshooting

The console is empty, no data arriving. Open Diagnostics and look at RX bytes. Rising while Frames OK stays at zero means bytes are arriving but falling apart — wrong speed, interference, or a shared port. Zero means nothing is coming off the serial line at all. Frames that cannot be decoded are printed in full hex.

The port is busy. sudo fuser -v /dev/ttyUSB.pa and systemctl status ser2net.

SET, BAND, ANT, CAT and IN do nothing while OPERATE and MODE work. The amplifier sees TX and locks everything that would move the RF path while transmitting. The console warns about this once TX with zero drive power has persisted for more than two seconds. The usual cause is a powered-off transceiver holding PTT.

Key probe in Diagnostics: sends a key, watches the state and reports what moved. Hold sends it 8 times a second for 1.5 s — both revisions give 8/s as the ceiling for the link.

Verifying against the hardware

1. With --auto-shutdown 0 and the amplifier already on: the readings and bars must match the front panel, and the RCU_ON watchdog must keep the stream up.
2. ON from the web raises DTR → the PA comes up in about 7 s.
3. OFF from the web drops DTR → the PA shuts down.
4. Confirm that 0x33 is C+ and not L+, by comparison with the original.
5. TUNE and OPERATE last, into a load.

Tests

./test/run.sh          # decoder and rendering, no hardware needed
./test/run.sh --e2e    # plus end-to-end against the simulator

decode.test.js and render.test.js run code extracted from index.html rather than a copy of it, so what gets tested is what actually ships. render.test.js uses a minimal DOM shim, which lets the rendering logic and the setup-tree walker be verified without a browser. bundle.py builds a standalone copy in a temporary directory and checks that it really runs with no index.html in sight.

Single-file distribution

expert_console.py always reads index.html from beside itself, so during development you edit the HTML and press F5. There is exactly one copy of the page, and nothing to keep in sync.

When you need one file to drop on another machine:

./expert_console.py --bundle expert-standalone.py

That writes a standalone copy with the page folded in — it runs anywhere with no companion files. The bundle is a build artifact, not a source: it is gitignored, and running --bundle on a bundle is refused.

Earlier versions folded the page back into expert_console.py itself. That left two copies of the same content, doubling every GUI change in the history and drifting apart whenever the step was forgotten.

Options

Option	Default	Meaning
--port	—	serial port, e.g. /dev/ttyUSB.pa
--simulate	—	synthetic amplifier (--scenario normal|alarm|hot)
--replay FILE	—	replay a socat -x -v capture
--record FILE	—	write traffic to a file
--listen	127.0.0.1	bind address for both HTTP and the raw port
--http-port	8080	console port
--raw-port	off	raw TCP for the original application
--auto-shutdown	0	power down after N minutes with no client
--dtr-mode	level	level = DTR high means on; pulse = ignition pulse
--dtr-on-start	off	power the amplifier up as the daemon starts
--dtr-pulse-ms	1000	pulse length, --dtr-mode pulse only
--bundle FILE	—	write a standalone copy with the page folded in, then exit

Scope

Out of scope: CAT_232 tuning, server-side telemetry logging, multiple amplifiers.

Sources

• EXPERT_1K-FA_RS232_PROTOCOL_2.pdf — protocol Rev. 2.0, covering the CE/FCC Compliant Second Series with firmware >= 07_07_07_M
• expert_manual_v20.pdf — user's manual (§18.17 has the fan thresholds)
• expert-console.sh + Expert_Console2.exe — the original console under wine

Support for Rev. 1.0 (firmware 06_11_06_x) is kept in the code, but its specification is not in this repository — it can be downloaded from linear-amplifier.com, as the opening notice in Rev. 2.0 points out.