Fan Dipole : How it works, a simplified explanation.
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- Опубліковано 22 сер 2024
- Fan Dipole : How it works. Aimed at anyone with an interest of DIY antenna building. this is a rather oversimplified explanation of how the "Fan Dipole" works.
As a cut length of wire is resident at a given frequency with a impedance of 50 Ohms, If you feed RF energy to the wire at the same frequency, the wire will radiate the RF with little to no returned energy. If however you move away from that frequency the impedance of the wire changes and the cut wire becomes resistive, the RF energy being pass it will start being return to to its source, (high SWR)
A Fan Dipole has multiple cut lengths of wire, resident and key frequencies and as the frequency changes so each length of wire becomes resident and the others represent high impedance and so become gated to the RF forcing the energy down the route of less resistance.
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Many thanks
Mike - M0MSN
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Thanks Mike love the round peg in a square hole analogy
Great video and easy to understand. I‘m right learning vor my Class E License in Germany.
You are a great Inspiration for this hobby.
Wow. Brilliant way of explaining. Thank you
Nicely explained. I have an indoor fan-dipole and it works well.
I'm amazed your able to get the vswr so low with the ends of the wires being so close to each other.
All of the fan-dipole designs I've come across suggest keeping each dipole end well apart (18 inch) or so.
A good simplistic approach to explaining the alchemy of RF.
Excellent explanation. I have built several /P fan dipoles, mostly 10, 20 & 40mtrs and tuned each leg little by little, but never really understood the "magic" behind it, now I do. Thank you.......
Yeah, good explanation. I wouldn't have thought of the child's toy bit, but it explains it well for those that struggle with it. Well done Mike.
brilliant video , well done, very clear and understandable
Many thanks!
Like the analogy Mike
Thanks
Interesting. Great Explanation.
Thank you!
Great video.
That is a simple explanation and easy to understand 👍🏻
Classic explanation
I only watched for the mention of inclement weather things 🤔
Seriously though, I'm a fan of an hf fan dipole. No pun intended. Good video, well explained
Terrific explanation. Learning a lot about antennas from you, Mike! 73
Thanks
Brilliant explanation! Thank you Mike!
I did wonder. And now it makes sense. Thanks Mike 😀
Beautifully explained!
A hexbeam works similarly to a fan dipole with the centre hub representing 50 Ohms.
Keep up the good work Mike and stay safe.
Kevin, VK4KK
I was following along fine with your description until you tried to use the analogy of the different shaped blocks. They're NOT 'different shapes", but rather different sizes of the same shape! In your first drawing, you drew antennas (antennae) of lengths that were exact doubles or halves of their adjacent ones (harmonic lengths, if you will). As a musician and guitar player, I recognize that these antennae will also resonate sympathetically on their first and second harmonics. I get the "path of least resistance" analogy. Is it more an issue of the "reactance" of each leg at the transmitted frequency that causes the resonance? Obviously, the transmitted signal is going through ALL of the legs. Is it the reactance to the frequency that causes each antenna leg to be resonant in the proper frequency or band? I'm thinking the signal is resonant to some extent on ALL of these legs!
Mike - cracking video! Callum could learn lot from you, hahaha (sorry Callum if your reading this but couldn't help myself mate)
I like Callum's explanations with everything explained in terms of 'bananas'. However not useful for taking the Ham exams.. They don't have that kind of sense of humor and want you to understand dB, dBm, dBV, and how to do the math.
Well explained. Cheers Mike
good video as always thanks mike
Hello Mike great video super work. Radio magic. Its just works. 👍🏻
Motters M7TRS 73's
Thanks M8. Great Vid and explanation
Another great video, thanks. I’ve been experimenting with a homebrew fan dipole but I’m struggling a bit with the elements interacting with one another, simply too close I suspect. Irrespective, they’re a great idea and this video is a super explanation of the theory. 73 M0EUK
Hi Mike,
Very plausible and understandable explanation. Stay safe. WJ3U
Thanks Don, it’s never easy to explain what my head is saying 😂😜🤪
Good comparison.
Well said that Man.
Another solid video, Mike...no ad issues, as well...thank you! 73! de WX0V P.S. You coax line drawings rule... :-)
Cool, thanks!
An elementary explanation of Kirchoff's law of currents and of the maximal power transfer with a parallel of resistors.
However the intuitive analogy you illustrated works only in the limit of a parallel of resistors with infinite values (and one finite). It doesn't address why resonance is not affected by neighborhing branches.
If the antenna radicals and reflectors are all insulated copper wire can you cable tie them together...all radicals together in parallel and all 3 reflectors together in parallel? If not how far apart should they be?
👍👏👏
Well presented, but I have a related question I think it does not answer... I built a fan dipole that includes a 10m band element and a 15m element. If I were to add a 40m band element, when transmitting on 15m which element would radiate, as I understand a 40m band one works for 15m? Serious question as I do want to add 40m to it, but I really want my 15m element to continue radiating on 15m as I have put a lot of effort into creating an efficient wideband element (more to it than just a thin single wire). So what happens in this instance when there's two holes that a peg will fit into? Wonder if you know, I haven't found the answer anywhere else yet. M7TDV
Great question and the answer is: there both do, however the 40m element is going to resonate slightly higher up the band than the 15m element unless you are going to load the 40m element in the same way that the DXCommander. You should find that most of the work will be done by the 15m element as it will be on the primary unlike the 40m which is on the 3rd harmonic.
@@mike-M0MSN Thank you Mike for taking the time to answer, very much appreciated. And with the answer I was hoping for too :)
Maypole antennas are the best