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TROUBLESHOOTING WORKSHOP

SWR too high?

Separate measurement setup, cable and antenna before changing antenna length.

Switch the transmitter off before working on the RF path. Never connect a VNA to a transmitting output. Consult each device’s manual for permitted power and SWR limits.

YOUR NEXT USEFUL TEST

Calibrate at the correct plane

A saved calibration is meaningful only for its associated setup and frequency range.

  1. Disconnect the VNA from the transmitter completely. Set the required frequency span and perform reflection calibration with open, short and load as specified in the model’s manual.
  2. Calibrate at the plane where the antenna or section under test will connect. Account for the test lead and adapters and leave them unchanged afterwards.

What to look for next

Use a suitable known load to check that the reading is plausibly near 1:1 there.

Related learning & practice

Technical sources for this check

Background and model-specific guidance; the check sequence is editorial. Match menu names against your own model’s manual.

Show check record
HB3YAQ · Check record: SWR too high?
Your answers; no automatic measurement.

1. Do cable, connectors and antenna connection look sound?
→ Yes, nothing visibly wrong
2. How are you measuring SWR?
→ With a VNA or antenna analyser
3. Is reflection measurement calibrated for this setup?
→ No, or calibration is uncertain

Calibrate at the correct plane
A saved calibration is meaningful only for its associated setup and frequency range.
1. Disconnect the VNA from the transmitter completely. Set the required frequency span and perform reflection calibration with open, short and load as specified in the model’s manual.
2. Calibrate at the plane where the antenna or section under test will connect. Account for the test lead and adapters and leave them unchanged afterwards.
Use a suitable known load to check that the reading is plausibly near 1:1 there.

NanoVNA · Calibration: https://nanovna.com/?page_id=2
RigExpert Stick 500 · User manual: https://old.rigexpert.com/products/antenna-analyzers/stick-500/users-manual/

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