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A quick question: Is it a disaster if the two legs of a v-dipole antenna are different resistances? Thanks.

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    $\begingroup$ I edited your question to indicate you were asking about the resistance of the two legs. If this is not correct, please re-edit your question to clarify. $\endgroup$
    – Glenn W9IQ
    Commented Oct 3, 2017 at 12:44

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If you are speaking of a different DC resistance in each leg, such as would be the case when different gauges of wire are used in each leg, this normally should not be a significant problem. If you are dealing with a very extreme case, you may wish to post more details.

What this would impact is the efficiency of the antenna. Efficiency is one of the factors that determine gain. But the radiation resistance of an inverted V is quite high, so any small increase in loss due to a different gauge of wire will have a minimal impact on efficiency or gain.

Feeding the antenna with a proper 1:1 balun will also help to minimize any side effects from minor loss differences in the legs.

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  • $\begingroup$ Since the DC resistance would also affect the phase between the two legs, directivity would also be affected, no? $\endgroup$
    – Marcus Müller
    Commented Oct 3, 2017 at 13:10
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    $\begingroup$ @MarcusMüller If it does, I think we are playing with decimal dust unless the OP's situation is extreme. $\endgroup$
    – Glenn W9IQ
    Commented Oct 3, 2017 at 14:11
  • $\begingroup$ that's not true. Imagine your dipole was two independent monopoles. Now do two different thought experiments: 1. feed the "left" monopole with let's say one eighth as much amplitude as the other. Does the main lobe of the dipole stay the same? In which direction is the main lobe directed? (hint: the "imaginary" ground plane that would be there for a monopole, emulating the other half of a dipole would get tiltet away from the stronger side) 2. let both halves be fed with the same signal, but one shifted by 135° (instead of the typical 180° of a balanced dipole). Main lobe direction now? $\endgroup$
    – Marcus Müller
    Commented Oct 3, 2017 at 15:39
  • $\begingroup$ @MarcusMüller Using an example of 1/8 of amplitude (do you mean current?) would be an example of extreme asymmetric losses. In your second example, shifting the feed point current phase is not germane to the question. $\endgroup$
    – Glenn W9IQ
    Commented Oct 3, 2017 at 15:54
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    $\begingroup$ @dickreid All the more reason to use a balun. $\endgroup$
    – Glenn W9IQ
    Commented Oct 7, 2017 at 0:43

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