RSGB: Useful practical skills - tuning a dipole with a NanoVNA
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- Опубліковано 16 вер 2024
- The fourth video in our ‘Useful practical skills for new licensees’ series focuses on tuning a dipole with a NanoVNA. Lee, M7MUT has made his own aerial and Rob, M0VFC shows him how to use a NanoVNA to cut it to the correct length for use on 20 metres.
We're providing these video resources to link with British Science Week and as part of our 'Get on the air to care' campaign with the NHS - supporting wellbeing amongst the amateur radio community during the ongoing restrictions when radio amateurs can't meet up.
Watch this and the previous videos in the series on our website: www.rsgb.org/practical-skills
Thanks RSGB 73's
When you cut the dipole close to resonance you can fold back the ends of each dipole on itself to better adjust for antenna height at resonance. That gives you the option of adding a bit on or taking a bit off without cutting.
That's a good point to make, and it is especially useful on 80m where the resonance of a dipole is not good enough, the SWR is not low enough, over the whole of the 80m band. It's best to tune an 80m dipole for the CW/DATA end around 3.550MHz (which is about 21.1m long) and then fold about 70cm the ends to move the resonance up for the SSB end around 3.7MHz say.
New to the channel. Nice video guys, I'll keep an eye out for other videos in the series. Good 'value add', RSGB! Chris (2E0FRU)
Excellent for anyone with this type of device and a Windows pc. 👍🏻
I use my nano vna and matching unit to tune my antenna, without any software. More enjoyable making notes and recording resonant frequencies.
Worth mentioning the likely reason for higher than desired resonance is likely that the 2 elements are not of exactly equal length before or after the adjustments were made.
In this case, it was simply proximity to ground: after we made the video, Lee managed to get everything rather higher, and it looked much more like the 20m dipole we were expecting to build!
@@M0VFC Nice adaptation on the fly! 73 de 2M0GUI
He!he! just found you!!
Nice video but I would have been much happier to work directly off the device. Cheers
Interesting, but what is the software called and where can I download it? Surely that should be at the start of the video or in the notes.
The video is about the NanoVNA - it explains just after a minute into the video what this stands for (Vector Network Analyzer). You can buy them online in many stores or there is a NanoVNA website which will tell you more - nanovna.com/ Hope this helps
Such a shame , this is not "tuning a dipole with a NanoVNA" it is "how
to use software to tune a dipole with a VNA " whats the difference?, a
computer no where near the antenna , software I dont have , and its not what I need as a beginner
who has just bought a NanoVNA. show it with out the computer and software
im sure it would be great sorry .
Hi Ian. Thanks for the feedback. You're correct that everything in this film can be done on the screen of the NanoVNA itself. We decided to demonstrate the NanoVNA Saver software because it is both easier to use (some NanoVNAs in our experience have slight offsets on the touchscreens, meaning you can push something you were not meaning to) and also because it was significantly easier to film via a computer screen-share when we were having to do all the production remotely. 73, Dom M0BLF (Series editor)
Thanks for the video. Don't you first need to take into account the velocity factor when sizing the length of the antenna? Or do you let the nanovna take care of that?
Thanks guys - that was very informative.
Is there any particular advantage to using a VNA over a standard VSWR meter ?
I am interested in getting one but I'm not really sure what practical advantages it has over traditional tools.
More video's on the uses of VNA's to Hams would be very interseting.
Thanks again, M7MGK.
There’s much more you can measure using a NanoVNA. Impedance btw and even the length of coax cables. Its like a Swiss Army knife not only one tool.
There isn't a single reason that an antenna MUST be resonant. Many antennas are intentionally NON resonant.
Absolutely, although technically the antenna will be resonant when the tuner has done its job