#1498

Episode 1498
having fun with antenna design
Be a Patron: / imsaiguy

[@ats89117]

When I was in college in the early 80s, a friend of mine had a business selling cable receivers and decoders to get cable TV for free. As you mentioned, the scrambling involved inverting the scan lines, but not the retrace intervals. Building kits for doing this was popular back then, and my friend's business was doing very well until they changed the scrambling method one day. Needless to say, my friend's customers weren't happy and he had to leave town...

[@namelessdata4608]

I remember those. They were still very popular in the 90s in eastern Europe. My uncle just DIY his own.

[@analog_guy]

For considerably higher directive gain, try the Inagaki three-sided corner reflector. It can be made with three reflector planes with 90-degree corners just like you built, but the planes are two wavelengths on each side. The monopole driven element is about three-quarters of a wavelength long, it is mounted on one of the planes as you have done, and it is spaced 0.9 wavelength out from the apex where the three planes come together. This arrangement produces about 18 dB of gain as compared to an isotropic (theoretical omnidirectional) antenna. The direction of maximum radiation is tilted out about 39 degrees from the corner that is parallel to and behind the monopole. The antenna is linearly polarized, with polarization parallel to the monopole. (Reference: "Three-Dimensional Corner Reflector Antenna", by Naoki Inagaki, IEEE Transactions on Antennas and Propagation, July 1974, pp 580 - 582.)

[@ismaeltorresmoreno5332]

thnx for sharing knowledge

[@tracyandmarctiritilli5734]

0:05 0:06

[@CaptainKirk01]

That's why they say RF is the Blackest of the Black Arts!

[@originsdecoded3508]

Very intersting that sound waves can be amplified to higher amplitudes when generated in next to wall corner, especially if the material deflects soundwaves, and that the same effect can be observed within electromagnetic signals in a corner. I have always found interesting how shapes in electronics influences and modulates flow electricity through the manipulation of the interaction of the magnetic flow, and how the same is true when it comes to manipulating vibration sound waves through shapes. So vibrations flowing through an object can be modulated, in very much similar ways magnetism and electricity can be modulated through shapes. If you make a bowl dish shape out of that same material and stick the antenna through it, I'm sure the signal would be amplified (satellite radio antennas), same amplification would happen if you were to put a mini speaker inside a bowl dish. Sound, vibration and electricity are inherently connected. You can even say that electricity is practically very high vibrations running through materials that when excited generate an electrical magnetic field which then conducts what we know as electricity. So it comes down to vibrations and proper materials to generate energy. as Nicola Tesla mentioned, If you want to know the secrets of the universe think in terms of vibration, frequency and energy. Vibration creates frequencies which generate energy.

[@jms019]

Please test the gain (which ought to be great but…)

[@hfn3778]

Trihedral corner reflector antenna Found a lot in classic RCS literature.

[@ZPapaGeek]

Made one of these as a wi-fi extender with a USB wi-dongle at the focus.

[@thorhilda]

That's a really fun project.

[@acestudioscouk-Ace-G0ACE]

What fun! Simple but very interesting. It would be interesting to see the effect of some yagi elements on and off the ground plane area and maybe extending the ground plane to the end of the new yagi elements. What effect would a "roof" element the same size and shape as the ground element have?

[@vk3zen-rfdesign980]

what frequency was it resonant at??

[@IMSAIGuy]

6:15

[@catalinalb1722]

Hello, I see there that the dip of the VNA is 2500 MHz, Can I have the measurements for that one? I would like to 3D print such a part and cover it in aluminium foil for the WiFi router at work. It has fixed antenna´s! Thank you!

[@cmseevers]

I refer you to a series of articles written by Dragoslav Dobricic, YU1AW on 2.4 Ghz antennas. He has one on corner reflectors similar to yours.

[@Burlaphen]

Awsome!!

[@robinbrowne5419]

That would be cool to make a slot so the antenna can be moved. It would be interesting to see how this affects the gain of the antenna. And even, perhaps, it's frequency. 👍

[@2321brendan]

What happens to a reactive impedance when transformed . ie 1ohm +j100 to 50ohm+j5000 ??? or It dont work that way.

[@Mooff2]

Imagine the copper plates were all mirrors. If you looked at it, you would see a phased array of four monopoles all leaning away from each other. I’m sure that would mess the pattern up somewhat but maybe not too bad.

[@therealjammit]

What about a stripline in the middle of the ground plane? Feedpoint in the front and a vertical soldered at the "best" point on the stripline.

[@xenoxaos1]

It's like a Pringles cantenna

[@K1ZEK]

I'm having to much fun 😅..No kidding 😂😊😊😊

[@jspencerg]

How is the frequency selected?

[@NavinF]

By changing the length of the monopole.

[@jspencerg]

@@NavinF ya, but what is the way to predict the frequency? Is it actually L= λ/4? Confirming expected details validates understanding.

[@gjbcapital1847]

@@jspencerg No, you need specialized software like cst studio to get the exact theoretical numbers.

[@jspencerg]

@GJB Capital A research project is not required. Just a few days points to find an empirical relationship to compare to "simple" theory.

[@georgesampson4714]

Awww, if CuriousMarc can build a whole Apollo communication system you could at least build another of these and test across-the-room comms. Or maybe you could use a passive corner reflector like NASA left on the moon and test short range radar.

[@cmseevers]

Hmm, that antenna looks way to long to be a quarter wave at 2560 Mhz. Looks more like 800 or 900 Mhz to me.

[@kostasspiliopoulos3352]

Hi....from Home Antenna Theory handbook? tks for video..73

[@IMSAIGuy]

I have not seen that book

[@qrpontheair508]

@@IMSAIGuy ok ...see the title above your notes(top of paper)...tks

[@jjoeygold]

Why not a CAN antenna where all sides have a ground plane

[@IMSAIGuy]

how about a 3D printed parabolic dish?

[@espenlyngaas9502]

Please test it! :)

[@zoenagy9458]

tryit wiith RC remote