I am planning to buy a Xiegu G90. It has an internal tuner that can tune up to SWR 5:1. Does anyone know if I have a resonant antenna on 40m, what I will have for a SWR on 80m?

  • 1
    $\begingroup$ Depends on the type of antenna, small loop, dipole, trap vertical, etc. $\endgroup$
    – hotpaw2
    Feb 25, 2021 at 0:33
  • $\begingroup$ Is your "resonant antenna" a center-fed dipole? $\endgroup$
    – Brian K1LI
    Feb 25, 2021 at 13:45
  • $\begingroup$ No it is a MFJ 5m telescope antenna on my car roof resonant at 20m and then a bottom coil attached to make it resonant at 40m. so wondering it I can tune it to 80m with the G90.. $\endgroup$ Feb 26, 2021 at 19:51

1 Answer 1


Very high. Harmonics work the other way around — antennas can be useful on higher bands than the design band, but almost never lower bands. A dipole cut for 40m might be good on 15m. An end-fed or a loop for 40m might be good on 20m and 10m. But pretty much any design of 40m antenna is going to be a half-size antenna on 80m, and very unlikely to be tunable with any builtin ATU.


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