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On the ENA I am receiving the message "Continuous switching may damage source attenuator". What corrective actions should I pursue?

(SUPPORTED MODELS IN BOLD: E5071C E5072A E5070B/71B E5070A/71A E5061A/62A E5061B E5063A E5091A E5092A)

The "Continuous switching may damage source attenuator" message is displayed when different power ranges are selected in multiple channel measurement settings. In this case, an error message is displayed in order to advise the user that source attenuator damage may occur due to excessive switching.

The following information is an excerpt from Chapter 3 of the "Keysight E5070B/E5071B ENA Series RF Network Analyzers User's Guide".

"For example: When Channel 1's stop frequency is 8 GHz and Channel 2's stop frequency is 2 GHz with a 0 dBm setting, the error message 'Continuous switching may damage source attenuator' is displayed because each selected power range is different."

A review of Figures 3-5 and 3-6 within the "Keysight E5070B/E5071B ENA Series RF Network Analyzers User’s Guide" reveals that the Channel 1 stop frequency of 8.5 GHz combined with a 0 dBm power level defaults to an auto power range of -25 ~ +7 dBm with a source attenuator of 5 dB. While a Channel 2 stop frequency of 2.0 GHz and a 0 dBm power level results in a default auto power range of -32 ~ +2 dBm with a source attenuator of 10 dB. Thus the analyzer is “continuously switching” the source attenuator between the 5 dB and 10 dB attenuator selections. Over time this could cause premature failure of the attenuator.

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When applicable, i.e. the user is attempting to make measurements on different channels that have overlapping power ranges in manual mode, the solution is to turn OFF the Auto Power Range function. Next set the power range and power level manually such that the desired levels and power bands overlap without changing the source attenuator.

The procedure for selecting the power range is as follows:

  • Press CHANNEL NEXT or CHANNEL PREV to select the channel for which you want to set the power range.
  • Press SWEEP SETUP.
  • Press Power.
  • Turn OFF Auto Range.
  • Press Power Ranges.
  • Press the desired softkey to select the power range.

Note that as channels are added to the analyzers display, the trigger mode for the new channels defaults to the Trigger Hold mode. Attenuator switching, and associated applicable messages, do not appear unless the newly added channel(s) has (have) been triggered either through a Trigger Single or Trigger Continuous selection.

[E5071C]
The E5071C frequency below 8.5 GHz model does not have mechanical attenuator, so the user does not need to consider power range.