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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

The measurement chain remains unresolved

If the known suitable load already reads unexpectedly high, the antenna has not been established as the cause.

  1. Recheck load specifications, adapters, reference impedance and connection. Compare as directly as possible at the calibration/measurement plane using known components.
  2. Substitute one component at a time or compare with a second suitable instrument. Recalibrate the VNA afterwards if needed.

What to look for next

Reconnect and assess the antenna system only once the reference is plausible.

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?
→ Yes, at the intended measurement plane
4. What does a suitable known matched load show?
→ Still unexpectedly high

The measurement chain remains unresolved
If the known suitable load already reads unexpectedly high, the antenna has not been established as the cause.
1. Recheck load specifications, adapters, reference impedance and connection. Compare as directly as possible at the calibration/measurement plane using known components.
2. Substitute one component at a time or compare with a second suitable instrument. Recalibrate the VNA afterwards if needed.
Reconnect and assess the antenna system only once the reference is plausible.

NanoVNA · Calibration: https://nanovna.com/?page_id=2
ARRL / Darrin Walraven · Understanding SWR by Example: https://www.arrl.org/files/file/Technology/tis/info/pdf/q1106037.pdf

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