Today I received a question about a post from 8 years ago: how to tame the static build-up in a GP or collinear antenna. Back then I had done some research and concluded that a high value non-inductive resistor could be used, especially at low TX power or RX only.
Now that I own a NanoVNA I can confirm that the impedance is not affected. I quickly reused the LoRA antenna from last Summer, which turned out to be resonating at 750 MHz (if we trust the NanoVNA). This is the curve on a 300 MHz span (well, it stops at 900 MHz on the right):
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| Just the "open" GP antenna. |
Then I added a 10 kohm 1/4W resistor across radiator and radials and the result is almost identical (the marker has moved):
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| After adding the 10kR across. See next picture. |
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| The very (quick && dirty) antenna under test. |
So, if we trust the NanoVNA at the upper limit of its working range, this trick does not compromise the impedance. I might also have been lucky on the single experiment I've made, so do your measurements first.
