Re: Searching for IMD

Warren Allgyer
 

Here is more data that I am gathering for my own reference. I am sharing for those interested. 

This characterizes the gain and drive requirements of the transmit chain at operating frequency from Q90 through the finals. Sweep generator was inserted at C80 and level adjusted first for nominal 1 watt indicated on the wattmeter (Purple trace) and five watts indicated (Blue).

- Gain of the chain varies from 56 dB at 3.7 MHz to 52 dB at 28.2
- Input levels at C80 were -24 dBm (purple) and -15 dBm (blue); note 9 dB input increase generates 7 dB output increase..... 2 dB compression and resulting unacceptable IMD (not shown)

WA8TOD

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