Ralph:
No, any reasonably conductive metal will have a free space
velocity factor of 1.0. However, putting conductive objects
very near to a metal wire or tube or rod will change this.
Also, any insulation on a wire will reduce the velocity factor.
I just bought a nanoVNA-F vector network analyzer for
$100 which will sort all of these tuning issues out quickly.
Sorry about the quarantine or I'd get you a hand with
this, but I'm hunkered down for the next few weeks here.
Does there seem to be a low SWR point somewhere near
to your operating frequency. The minimum SWR point
and the resonant frequency are generally not the same
but should be close enough for rough tuning purposes.
Gary, K5AMH
On 4/21/2020 2:52 PM, ralph phillips via BVARC wrote:
Having problems with my home brew 440 mhm jpole...will not tune better
than a SWR 1.9. Books and articles no help. Will velocity factor or
resistance change dimensions for steel vs aluminum??
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--
Gary Sitton, K5AMH
[email protected]
SDR/DSP Consultant,
"Have FFTs, Will Travel."
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