[Elecraft] KAT500 Attenuator

[Andy Durbin]

" Have we, in fact, established that this attenuator is enabled at any point of the tune cycle? Because if not, then we're all spun up for nothing."

KAT500 Serial Command Reference Revised 8/18/2021 firmware version 02.00 says:

"ATTN Enable Attenuator GET format: ATTN; SET/RESPONSE format: ATTN0; (disabled) or ATTN1; (enabled). Selects relay K22, which switches in an attenuator resistor. It may take a few milliseconds after issuing an ATTNx; setter before the relay changes. Firmware releases the attenuator if it detects power high enough to damage to the attenuator. Firmware normally inserts the attenuator during “full search tune” to present a more consistent load to a transceiver during tune operations. The attenuator is disabled if the tune power is too low with the attenuator in place."

This version was released so the document was compatible with firmware 2.05 changes.

As I have said earlier in this thread I see no evidence that ATTN changes state during a "full search tune".

We are left with an attenuator design change that no one seems to understand and documentation that may not be correct.  Whether that is "spun up for nothing" probably depends on one's perspective.

Andy, k3wyc