Before you transmit¶

This board has a power amplifier: about +19 dBm out, against a receiver that survives +2.5 dBm.

Two rows. With the attenuator: TX1A at about +19 dBm, through a 20 dB attenuator, reaches RX1A at about -1 dBm, under its +2.5 dBm limit. Without it: +19 dBm goes straight into RX1A, about 16 dB over the limit, and destroys it.

Rule
1. Put at least 20 dB of attenuation in any TX→RX loop	without it, the transmitter destroys its own receiver
2. Terminate every transmit port, or leave it unused	never transmit at power into an open port
3. No antenna on a transmit port you do not want radiating at power-on	every power-on emits a ~4 ms burst on both transmit ports, before any software runs
4. Affirm the channel before raising it	`./devkit tx-guard affirm 0` for TX1A, `1` for TX2A, after looking at that port

# run from: the repo root
./devkit tx-guard affirm 0        # only after LOOKING at TX1A
./devkit tx-guard revoke both     # withdraw, and force maximum attenuation

Writing your own transmit code? Two more rules apply: set the attenuation after the buffer starts and read it back, and mute before tearing the buffer down. Why, with the measurements: transmitter safety reference.

Next: use the radio: capture IQ or SDR++.