With the adjustments on a transmitter such as a Yaesu FT-101E, is there any purpose for an antenna tuner, or can you accomplish the same thing by adjusting the loading and other controls?


2 Answers 2


The original Yaesu FT-101 tuning instructions state the following:

Do not use antennas which are untuned or exhibit an SWR of more than 2:1.

An external antenna tuner can usually work with a much broader mismatch range. If you have a "random wire" or otherwise untuned antenna, a tuner is clearly required. A slight mismatch (2:1 or less) can be handled by the tube amplifier's controls.

The same advice will apply to other tube finals.


I don't believe an antenna tuner is needed if the power levels are 100 W or less. Doesn't your manual tell you how to attach to an antenna and how to insure that power is going to the antenna? I remember tuning the power out to a light bulb and then attaching the antenna. Anyone else remember that?

  • 2
    $\begingroup$ This isn't true, power level has no relevance on whether a tuner is required. Even at five watts, an untuned and mismatched antenna can damage your transmitter. $\endgroup$
    – Dan KD2EE
    Commented Oct 30, 2013 at 13:40
  • $\begingroup$ Back in the early 1960s with my Eico 720 (PA, 6146B) I never owned a tuner. In fact, I never knew anyone who owned a tuner. And, that included a lot of young hams like myself. I had a 40 meter dipole that was short as I did not have enough room for the full size. However, during my Novice year, I had a couple of thousand contacts using my Eico transmitter tuned into that antenna. SWR? No one cared. My output power was officially 75 watts (then the legal limit for Novice) but I ran full bore producing 90 watts. However, that is 90 watts DC input as they measured power in those days. $\endgroup$
    – K7PEH
    Commented Dec 8, 2016 at 18:36
  • $\begingroup$ Yes, I know, this post is three years old. $\endgroup$
    – K7PEH
    Commented Dec 8, 2016 at 18:37

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