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Nearly everything we know and use is based on science from the past few centuries. It's easy to think that everything we create and use today has been discovered//designed in the past 20 or so years,

I don't know who you are as you have not identified yourself. But yes but the author did not explain himself. 1.??? Take ONE end of the _electrically half wave-length of 75 ohm coax_ (RG-79 type)

Don't overlook the simple stuff. Disconnect the coax from the antenna and use an ohmmeter to check for shorted coax, especially if you are not really confident in your quality of connector assembly.

really both. Sure, there's been innumerable variants of helical antennas developed over the years, and there's papers describing them, but the basics are pretty what Kraus figured out in the 40s.

Yes, indeed, Mr. J. D. Krauss is the master of the helix! Dave - W?LEV wrote:

Interesting that a book written in 1950 is the authority on the helical antenna. From the stand point of theory or practical application? Roy WA0YMH

True. It's a pretty bad antenna even at HF! When that much loss is shown even in the first plot and progressively measures more and more as you step upward in frequency, the loss is all there is.

WiMax? there's a bunch of antennas made for 3.5 GHz >

The general design concept is that the circumference of the helix is approximately a wavelength, and the "pitch angle" is around 12-14 degrees. and the spacing of the helix turns is around 1/4 the

The "natural" impedance of a multiturn helix is about 100 ohms. One either does some sort of matching transformer, or, you adjust the spacing of the turn closest to the ground plane to essentially

Remember, resonance is not defined by lowest SWR, but at the frequency at which the complex portion of the impedance goes to zero. Helices are traveling wave antennas, not shortened 'rubber ducks'. \

Because of the nature of a helix, I found the precise measurement of the inner diameter open to error, so I'd ignore that. The conductor gauge is 4.85mm.

Oh I see, I didn't realise this group was for SAA2 versions only. I chose here as it seemed the best place to ask as it's an actual practical application (the frequency range here is irrelevant here

The diameter is about right, but 10 mm conductor is certainly out of the range forall of my charts.

Thanks again. Details here: Loop spacing: 21.5mm Loop diameter (inner): 36mm Loop diameter (outer): 46mm 19 turns

Many thanks! I should have thought of that, hindsight 20:20, etc. -- Best Regards, Tom, VA7TA

You need update firmware on NanoVNA for work (nanoVNA-App need new format for data exchange)

Greetings, I decided to give NanoVNA-App a spin for the first time and I am impressed with the appearance of the GUI. But it runs OK with my TinySA but not with either of my nanoVNAs. My attempts to

Well, gentlemen......... ( um, and ladies) This might not be technically the correct forum. The frequency of discussion is above 3ghz, which is out of the range of all the nanovna devices which are

Send me the dimensions and I'll have a look. While it may have a good Return Loss at 3.4 GHz, that does notmean the radio waves are going out the front of the antenna!? hihi