Antenna length: Where to measure from?


Attached is a picture with four points labeled as possible locations to measure from when tuning the antennas to 1/4 wavelength. Which is the best and correct point to start measuring from?


It’s doesn’t necessarily require that much precision. I’d probably just measure from around the coax junction.

To find the correct length, you’d need an antenna analyzer.

But any movement when driving throws it off as well.

So back to no big deal, except all the same.

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Thanks for the reply. Say theoretically I wanted to be as precise as possible and had a antenna analyzer. Would I only need to be checking the VSWR, and hoping for a 1:1?

Yes, but you’ll never get a perfect 1:1. These antennas have a loading coil which means that almost any length will work for most frequencies, but you can tune them better using a VNA.

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Hello, I would like to know if I can change the antenna by others. I wish use wide-band antenna. Like that, I avoid adjusting the height of the antennas depending on the frequency. can you tell me what you think about it?

You can use a wideband antenna, but what options do you have? A discone is a great wideband antenna, but it’s too big to use at the smaller spacing radii. The antennas shouldn’t overlap one another.

Of course, you’re right and I know it. However I found an antenna that does not take up too much space and preserve spacing radi. Have got an other question, I thought there was an master antenna identified on the antenna’s krakensdr who pilot the others. If I change all with wideband, how do I declare the new master antenna ?
Thank you for your answer

The master antenna is the reference antenna. All the 5 antennas need to be identical. You don’t need to declare a new reference antenna.