Clanker: Rework documentation for new users: illustrated steps, clear navigation, preserved technical references, and current 0.3.6 behavior

2026-09-13T21:22:05Z

Rework documentation for new users: illustrated steps, clear navigation, preserved technical references, and current 0.3.6 behavior

← Older revision		Revision as of 21:22, 13 September 2026
Line 1:		Line 1:
			{{Documentation navigation}}

	The simulated power amplifier (PA) heats up under load, reduces power to protect itself and can suffer permanent damage when abused. Its state is visible on the '''TEMP''' meter of the Radio Deck and in the deck header.		The simulated power amplifier (PA) heats up under load, reduces power to protect itself and can suffer permanent damage when abused. Its state is visible on the '''TEMP''' meter of the Radio Deck and in the deck header.


			== What to do when temperature rises ==
			Watch '''TEMP''' during long transmissions. If it approaches the foldback region, lower power or stop and allow a pause. Check final drive and headroom if a radio preset has been changed.

			'''Foldback''' means the simulator reduces output to protect the amplifier. Reduced FWD power can therefore be a heat warning rather than a network or audio problem. The damage described here belongs to the simulated session, not the computer's radio hardware.

	== Heating ==		== Heating ==

Clanker: Create PA behaviour page

2026-07-05T08:44:21Z

Create PA behaviour page

New page

The simulated power amplifier (PA) heats up under load, reduces power to protect itself and can suffer permanent damage when abused. Its state is visible on the '''TEMP''' meter of the Radio Deck and in the deck header.

== Heating ==
Transmitting dissipates heat in the amplifier finals. The temperature shown on the TEMP meter starts at room temperature (about 24 °C) and rises with output power, duty cycle and drive level. Constant-envelope modes (FM, CW key-down, steady tones) heat the amplifier considerably faster than speech on SSB, which has a low average power. When transmission stops the amplifier cools back down over time.

== Thermal foldback ==
When the finals get hot the amplifier automatically reduces output power:
* Foldback begins at roughly '''78 °C''' and the deck header shows a thermal foldback notice.
* It becomes aggressive above roughly '''92 °C'''; forward power visibly sags.
* The header shows '''PA OVERHEATED''' while the amplifier is in thermal distress.
Foldback is protective and reversible: power returns as the amplifier cools.

== Permanent damage ==
Sustained operation above roughly '''110 °C''' starts to damage the finals. Damage:
* accumulates faster the hotter the amplifier runs (minutes just above the threshold, seconds at extreme temperatures),
* is permanent for the session; cooked finals do not heal on cooldown,
* permanently reduces the achievable output power and adds distortion and slow drift to the signal.

== Operating guidance ==
* Watch the TEMP meter during long transmissions, especially FM, AM and digital modes at full power.
* If the temperature approaches 78 °C, reduce power, shorten transmissions or pause between overs.
* High final drive and low PA headroom (see [[Advanced Transmitter Settings]] and [[Radio Presets]]) increase dissipation at the same output power.
* A badly matched antenna also stresses the transmitter; the protection circuit reduces power at high SWR, see [[SWR and Transmitter Protection]].

[[Category:SimTX]]

Power Amplifier Behaviour - Revision history

Clanker: Rework documentation for new users: illustrated steps, clear navigation, preserved technical references, and current 0.3.6 behavior

Clanker: Create PA behaviour page