can anyone tell me if this is possible ,i need to measure my antenna impeadance at 3.775 mhz,i have asked on a few forums but no answers,if its possible how do i do it,thanks and a happy new year m3vuv.

On 01/01/2023 20:56, paul larner wrote:
> can anyone tell me if this is possible ,i need to measure my antenna impeadance
> at 3.775 mhz,i have asked on a few forums but no answers,if its possible how do
> i do it,thanks and a happy new year m3vuv.

Paul, Happy New Year!

A Google search gives dozens of videos, for example:

https://www.youtube.com/watch?v=xa6dqx9udcg

There are a couple of presentations to an Amateur Radio club as well, both well
worth watching - not sure whether these are the correct pair:

https://www.youtube.com/watch?v=5I6WQFdSHkQ&t=8s
https://www.youtube.com/watch?v=2I5e3j7R7ho

The RSGB has a couple as well:

https://www.youtube.com/watch?v=YTzGjLOV1mk

I hope they will answer your question!

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv

Happy New Year to you as well.

David has already given you a number of links to follow.   YouTube has many videos available on the use of a NanoVNA, all of which will be helpful.  Do a search there for NanoVNA and you will have all the information you desire.

You are on the forum for the NanoVNA V2 so I will assume you have a V2, or at least asking your questions in the context of a V2.    The V2 can measure down to 50kHz.

The short answer to your question is:  Yes, it is possible to measure the impedance of an antenna at 3.775 MHz.  To do so, you will need to calibrate your VNA (see videos for demonstration of how) for the frequency range of interest.  Configure your unit for an S11 measurement using the Smith Chart. Connect VNA to antenna feed-point.   Move cursor to frequency of interest.   Read the value.  Done!

Hope that helps.

Is it possible?  Measuring impedance is one of the basic functions of VNAs!

W2AEW has a number of excellent videos on VNAs, one of which David J Taylor has already given you a link to.  Here's a link to all of W2AEW's videos:

https://www.youtube.com/@w2aew/videos

All of W2AEW's videos are excellent, regardless of topic.  Highly recommended.

IMSAI Guy also has some good videos on VNAs, most of which are specifically on the NanoVNA:

https://www.youtube.com/@IMSAIGuy/videos

I wouldn't say his are as consistently as high quality as W2AEW's, but still absolutely worth watching, and he has a LOT of them, and on a wide variety of electronic topics.  Also highly recommended.

Happy New Year, Paul. I think David, GM8ARV, gave you  the best leads there, so I have nothing new to add. If I were you, I would go to the very first link he lists, the YouTube video by W2AEW. This guy is extremely knowledgeable, and has a great YouTube channel on a whole host of electronics subjects of interest to hams. He presents the information in a very organized and easy to follow style. Very understandable. If you haven't already, watch the W2AEW video. This video is only about 6 minutes long. To be clear, I'll repeat the hyperlink the David supplied here:

https://www.youtube.com/watch?v=xa6dqx9udcg

73,
Scott
KF7GGN

That was a nice video.
He had everything working well. A long ago, I noticed that dipole antennas need a balun. I was testing a random VHF antenna (two pieces of wire) indoors and didn't get any results until I put a balun next to the antenna feed point.