Easy to adjust DIY Delta loop antenna for 50 MHz (6 meter band)
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- Опубліковано 4 тра 2023
- Simple wire and a stick makes a good performing antenna, under the roof, above or aside the roof.
Easy way to adjust the frequency without cutting the wire.
Instead of twisting the wires you could also be kept close together by a tywrap that could be slided over the two wires.
Not critical but I forgot to mention what wire I used: 0.5 mm2 insulated flexible copper wire.
Simulation and measurements are performed about 10 meter above ground.
Twisting the wires to reduce the loop size without effecting ohms is brilliant!
Thanks! In fact, twisting is not needed, it is also possible to slide (for example) a cable tie over the wires. The only thing is that the wires needs to be kept closely together to form a low impedance open line.
Very nice and easy project. Good idea to twist the wires for SWR adjustment. I have built this antenna to be at least QRV on this band, and i am very surprised by the performance. Worked whole Europe with this simple piece of wire. Although, i have used a plastic tube instead of the wood. Thanks a lot for showing us! 73 de DO1LR
Thanks for letting me know and your kind words. In fact, twisting of the wires is not needed, they could also be straight parallel. By twisting them (a bit) the distance is guaranteed over the whole length.
Antenna looks good - nicely explained. Good Job. 73 de Uncle Günter 💯🙋♂
Thanks for your kind words Uncle Günter!
Good job thank u , if i intend to build delta loop for 2 meter 145.5 mgh what is the right length should i measure with no unun install 73’s
When simulated for 145.5 MHz I come to the following dimensions: horizontal wire 55.4 cm, sloping wires: 85 cm. However, I experienced that dimensions of single loop VHF antenna’s with MMANA are not very reliable… See also ua-cam.com/video/INEdbw4B37I/v-deo.html
If you keep the wire some longer then mentioned above and you measure a better SWR low in the band, it is indeed too long and you can shorten it a bit.
For measurements it is preferred if you use use a common choke, like ua-cam.com/video/gdTrNMh_LO4/v-deo.html
If you post here your findings, it could help others. Enjoy the experiment!
can you please share the calculations or ratio for changing the sides so the feed point is 50 ohms?
The ratio is 1 (horizontal wire) to 1.5 (sloping wires). So in fact, the horizontal wire is a quater wavelength. Simulation showed then an impedance of 55 Ohm and jx 0. So coaxcable could be connected directly to it for a good SWR. (Of course this change a little bit depending on antenna height). Make some turns in the coax to act as a choke. Please let me know about your results.
Cool project. Do you have a hard copy of plans for the antenna? Did you use 468 or 234 to figure out the wire length? Thanks for sharing. KC3UEE.
Thanks for your kind words. I am not sure what you mean by '468 or 234'... I played with MMANA. My dimensions are at the end of the video, at 8:22. The sloping lines ar each 2.16 mtr and the horizontal wire is 1.84 mtr. So the total length is 6.16 mtr (that is too long but that can electrically be reduced the way I showed). No hard plan, it's just a wire and a stick :-)
@@chrix2381 I meant is calculated by dividing the frequency by 468(half wave) or 234(quarter wave)?
@@chrix2381 I was referring if you used the frequency calculation of 468(half wave) 234(quarter wave) to get the length of the wire.
Ah, I understand. In Europe we use 300 to get the wavelength in meters :-) 300/50.3=5.96 for the full wavelength. And because it is insulated wire the length should even be a bit shorter. With my method to reduce the length of the loop by making a small 'open line' the effective length can be reduced but not lengthened. So in this case a bit longer is better then a bit shorter.
I played some more with MMANA: if the total wire length is kept the same and the horizontal stick is further reduced in length (to for example 1.66 mtr), the the impedance lowers further. So in fact, it is all not critical.
What would be the wire length for 11 meters?
I would say, 300/17.1=11,07 meter. This is likely too long but with the described method the effective length can be reduced. Just experiment, what could you loose? Please post your final results here.
Simulating for 27.1 MHz with MMANA showed some longer wire with a total length of 11,86 mtr?
Triangle dimensions:
horizontal wire: 3.54 mtr
wires connected to the coax: 4,16 mtr
Just play with the lenght and the shape, it's just wire :-)