DK7ZB yagi antenna

Hi
I recommend DK7ZB yagi antennas. I built this one: 5-Element-50-Ohm-Yagi for 70 cm.
https://www.qsl.net/dk7zb/start1.htm
I used 6mm aluminium rod.
Node is mount on my roof 11 meters above ground and it’s powering by 6m cabl from USB charger. I added a Li-pol 4000mAh battery.
It works perfect.


And some tests (signal always above 65%): pan nab pan terp

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I’ve been building DK7ZB antennas for a long time and I can attest their worth. Stick with the 50 Ohms designs, as they’re the least critical, but please do try to work with sub-mm precision when cutting and positioning the elements.

Also, place a couple of ferrite beads on the feedline, as close as possible to the radiator, to improve currents balance.

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st-pr profil
Works fine for a week. I’m waiting for really bad weather.

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The snowstorm does not disturb the connection. :grinning:

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I had to do a double take on your pictures. I think it’s cool that you put the radio inside an enclosure that is the main radiator for the antenna. Very innovative!

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Having the radio enclosure being the radiator is an amazing idea. I’m tempted to try this out. The test results are really impressive, and might be what I need for the jungle experiment.

This antenna is for 433Mhz correct?

@msws would you mind posting more details on the build? All the necessary materials, the rod used for the boom, etc?

Found this 6mm aluminium rod on local shop, is this similar to what you used?

This antenna is 433MHz.
The rod, that you found, is ok. You can use a different diameter.430MHz tabela


I can send more photos with construction details.

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:heart: Thank you very much.

The more details you can post the better so that we don’t make stupid mistakes.

Compared to the hills is your tests, jungle trees should have better propagation, is it correct to assume that?

Yes, longer waves are better in the woods, shorter waves are better in urban areas.

With these clamps the elements are mounted isolated 2-3mm above the boom. The screw has 3mm and is stainless steel. Boom is 15mm square aluminum profile.
The distance between the radiators is 8 mm. Remember that the length of the radiator is measured end-to-end (323 mm with the 8 mm, so the aluminum rod is two pieces per 157.5 mm). The housing is sealed with a polymer adhesive

I keep my fingers crossed for your project

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:pray: Thank you very much @msws. Your tips, images and schematic are priceless!

I’ll get some 433Mhz radios and reproduce your setup as soon as I have some time.

That 2-3mm between elements and boom made the clamps are fundamental?

No. It is important to insulate components from the boom. You may use plastic plate (1mm thick) cut from canister.

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@msws I only found 1cm/10mm rods in local shops. Is there a way to change the calculation in order to use them?

If not I’d have to order online, which is actually more expensive.

No, it won’t work. You must use 6 ,4 or 3.2mm, according to the table in my previous post.

Ok thanks!

Another question. How did you connect the antenna to the device? Did you just strip the ipex antenna cord?

Yes. I cut the SMA connector. I used small metal screws to connect the wires. The wires were covered with solder.

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http://www.vk5dj.com/yagi.html

All that for 5.23 dBd?

DK7ZB antenna gain is 8,7 dBi.

New version with choke:


Almost perfect

Dipole handle STL:
https://drive.google.com/file/d/1gu6lyPdY-uQkWac3D6D3WSaaQT-T1fbC/view?usp=sharing

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Your dipole bracket has a very interesting design, really clever!

However, a single turn of coax may not present a high enough impedance to common-mode currents. Further, it might be better to have the coil perpendicular to the dipole plane and closer to it, to avoid pattern distortion. But ferrite beads are really the easiest solution to raise impedance :wink:

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