Front End Protection

  • Question
  • Updated 1 year ago
  • Answered
How does the antenna switching work between Transceiver Antenna Port 1, SCU-A RF Input, and SCU-A RX Loop Output? I have the 6700 so there is also SCU-B.

What is the maximum signal before damage will happen? What components are at most risk? Can front-end protection be added in the "loop" area before the components most in danger?

Understanding high power band-pass filters is the normal but they will not protect from two stations on the same band (CW and Voice or Digital) on beams pointed at each other. The thought of blowing the SCU digitizer is scary.
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Stan - VA7NF

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Posted 1 year ago

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Photo of Steve - N5AC

Steve - N5AC, VP Engineering

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Official Response
Overload is at +9dBm on both SCUs and protection trips in at about +17dBm as I recall. A signal at overload will not damage the ADC, but it is the start of distortion from being too large. Damage occurs at a level above +20dBm, but the radio is designed to disconnect the antenna before this occurs (probably shouldn't test this at home though ;-) ). The path from ANT1 through RXA-OUT has no protection to speak of -- you are primarily going through relays to get to the SCU0 input. The protection is on the RXA-IN before it gets to the ADC in SCU0.