Re: Measuring R,X Resonant Frequency
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Well, can anyone come up with a case where the VSWR measures at 1:1 and the Smith chart is not on the zero reactance line. And in fact for 1:1 you would have to be dead center, based on analysis performed by the seat of my pants. But I am open to mathematical sets of R+iX that reads 1:1. just too lazy to work it myself. HI
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beach.jpg Lester B Veenstra K1YCM M?YCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1) lester@... 452 Stable Ln Keyser WV 26726 USA GPS: 39.336826 N 78.982287 W (Google) GPS: 39.33682 N 78.9823741 W (GPSDO) Telephones: Home: +1-304-289-6057 US cell +1-304-790-9192 Jamaica cell: +1-876-456-8898 -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of W0LEV via groups.io Sent: Sunday, January 19, 2025 7:37 PM To: [email protected] Subject: Re: [nanovna-users] Measuring R,X Resonant Frequency Any of the NANOVNAs are well suited to make your desired measurements: SWR and R ± j X. Minimum or 1:1 SWR is not a good indicator of resonance, regardless of ham "lore" and misinformation. The DEFINITION of antenna or lumped element circuit resonance is the frequency at which the complex portion of the impedance becomes zero leaving only pure resistance. Addressing an antenna, this resistance is a combination of resistive losses in the system and the radiation resistance of the antenna. SWR, alone, is incapable of indicating that condition as SWR is a scalar measurement (amplitude measurement only with no phase information). The total impedance expression requires a vector measurement of the impedance which also expresses the complex portion, the ± j X term. Dave - W?LEV <> Virus-free.www.avg.com <> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Sun, Jan 19, 2025 at 7:14?PM Peter Jones via groups.io <jonesypeter= [email protected]> wrote: Greetings, I've recently completed the construction of my first 'home brew' antenna (1/4 wave vertical). A radio friend of mine suggests I should look at resonance as well as SWR. SWR is fine, but I can't see anything online about an R/X chart (similar to that available on the RigExpert). Can I do this on the NanoVNA V4? Thanks Peter M0LMG [img][/img] -- *Dave - W?LEV* -- Dave - W?LEV |
