#1473

[@IMSAIGuy]

I'm doing another video where I solder down the coax.

[@marcino8318]

those holes are for mounting handle to carry antenna for wideband sniffing.

[@milesprower6641]

Try connecting the NanoVNA to a computer via VNA Saver. You can do higher resolution scans and save the graphs as images and insert them into the video directly. Even annotate them.

[@KG4JYS]

Pretty sure the holes are where you can strap the cable down with a zip tie. I've got a similar antenna that came inside a housing and was attached that way.

[@Electrotech1980]

Keep at it, love your videos. Keep in mind that the Nano VNA is feeding square waves into the antenna and wasn't able to replicate the readings common to your expensive machine.

[@__--JY-Moe--__]

gramps has got to tell us how everything works! he's the only 1 that can calibrate the machine! *the oppositional reluctance dipole antenna* ! never heard of one! I'm sure it works 4 the Union ! good luck Pat.

[@cowshittt]

Soldering down a coax to the boars should improve the performance. Soldering the cable to the antenna is the missing BALUN .

[@IMSAIGuy]

probably, it stumped me why it had the big ugly connector. what's the point if you are going to solder it

[@cowshittt]

@@IMSAIGuy That connector makes no sense.

[@khimbittle7705]

antennas! not getting bored

[@fannyjim6094]

Incredibly work!

[@espenlyngaas9502]

We're not getting bored!

[@TheElectronicDilettante]

How about opening the insulation and soldering the coax only where it intersects each element? What would be a good functional test? I’ve tried using Vistumbler with various 2.4ghz/5ghz antennae to see the number of access points I can reach with one antenna versus another. Quick note… I vote for the return of story time and IMSAI Dog. Have a good day!

[@KossuJahvetti]

Great video! Is it possible to design "log periodic antenna" for two bands, example 800-900Mhz and 1700-1800Mhz if frequencies between is not in your interest? Aiming of course keep the boom length reasonable with most gain on those two bands.

[@diemaschinedieviereckigeei2941]

It would be interesting to see, how efficiently this antenna really performs at the high end of the specified band. The PCB material seems to be standard FR4, which gets increasingly lossy above 1-2 GHz.

[@zerobow9413]

FYI the nano VNA has software might look better

[@byronwatkins2565]

I think the holes are for mounting and zip-tying the cable.

[@PlaceholderforBjorn]

I've seen on some trading sites that those holes doesn't have any function on the antenna design. But is intended for a mount, like a pistol grip.

[@IMSAIGuy]

ray gun

[@silverXnoise]

I assumed it was to zip-tie the cable, although they're spaced a little too wide for that. +1 for ray gun.

[@ivolol]

One IMSAI Guy's journey through aliexpress to find the best antennas in the land! Does your NanoVNA have an ability to screen capture into a computer or USB stick or similar? I'm not sure if you have a video on it already, but I'd be interested to know why your HP thinks it can get to 15-20 -dB whereas the nano was only reporting around 10.

[@IMSAIGuy]

I guess you get better numbers when you pay $30,000. Or it might be due to the HP connector attached to ground and helping out

[@MrMersh-ts7jl]

freshly calibrated machine. I see what you did there. 😂

[@IMSAIGuy]

thanks for reading the fine print! 😎

[@1shARyn3]

holes as passthru for zipties to hold the transmission line?

[@uni-byte]

The only way the soldered down coax could work is if that buss was connected to the shield. If it was connected to the center conductor that operation would leave you with .. not much.

[@IMSAIGuy]

of course is the ground side design: fenix.tecnico.ulisboa.pt/downloadFile/844820067125562/Extended_Abstract.pdf

[@pbaemedan]

I have 4 of this type and that I use for EMI pre-compiance testing.

[@knglaser]

I would call that a "logperiodic looking object" which does not do what it's supposed to. the elements are on top of each other, no interleaving, not a logperiodic.

[@IMSAIGuy]

did you actually watch the video??

[@knglaser]

@@IMSAIGuy yes, the whole one. perhaps missed some language hints (:

[@IMSAIGuy]

@@knglaser they are not on top of each other, they are staggered and out of phase.

[@knglaser]

@@IMSAIGuy wow, I stared at the end where there was closeups and thought there was copper under each of the silkscreen legs, quite hard to spot that detail

[@robinbrowne5419]

More antenna voodoo :-)

[@Stevef-sk3jc]

hows it perform, i bet its gain is bad due to the circuit board blockage

[@K1ZEK]

Boy you have a tough audience. LOL It would be fun putting it in front of a parabloc reflector and using it as a feed! Scanning the sky😮. 73. Leo

[@IMSAIGuy]

It's a tough crowd and occasional heckler. I will not be scanning the sky as I don't speak Martian. 😎

[@K1ZEK]

@@IMSAIGuy I have about 8 satellite dishes installed that I poke around the sky with. Hoping to get back to it soon. It's like SWL but higher frequencies. 73 Leo

[@chrisscott1547]

I'm not sure why Yagi is in the title - it is certainly not a Yagi - just adds more confusion. It looks a bit like a log periodic, but until we see directivity and front-to-back ratio, perhaps we should categorize it as Just-a-Bunch-of-Dipoles. It would not surprise me if directional performance is very poor and it's a complete fraud. EDIT: (Mark subsequently corrected the title, removing Yagi)

[@____________________________.x]

Why is the feed element on the opposite side from say a Yagi?

[@IMSAIGuy]

the shorter wavelength will choose the short dipoles if fed correctly, if fed from the other end then the short wavelengths will find long dipoles and odd things will occur.

[@nickcaruso]

What are you doing with these antennas? Inquiring minds want to know!

[@none_of_your_business]

what's the smallest HF antenna that you could have? could you possibly hang one out the window of an apartment?

[@IMSAIGuy]

you can use antennas designed for cars, or put a wire antenna under the eves of the roof, or in the attic. search around, there are thousands of people who have tackled that problem.

[@darkobul1]

Can you use vna to analyze transformers ?

[@IMSAIGuy]

sure

[@jeffreyyoung4104]

What happens if the antenna is fed from the aft end? Does it have to be fed from the front, just because the TV antennas were?

[@IMSAIGuy]

it won't work right. the shorter wavelength will choose the short dipoles if fed correctly, if fed from the other end then the short wavelengths will find long dipoles and odd things will occur.

[@jeffreyyoung4104]

@@IMSAIGuy I never looked at it that way, and that makes a lot of sense now!

[@Yuēhàn24]

Log antennas are not 50 ohms, so you need a balun.

[@IMSAIGuy]

actually the PCB designs are made to operate at 50 ohm and get better than 10dB across the range. There are several papers on line. They are supposed to have a soldered down coax. I will need to take off this silly connector and give it a try

[@willthecat3861]

​@@IMSAIGuy The balun (and matching) network are etched on the pcb The holes, in the pcb, are part of the matching network... and a possibly for implementing 'opens.' There a similar Chinese design... to the one you show... that uses a conductor backed coplanar waveguide to match.

[@IMSAIGuy]

fenix.tecnico.ulisboa.pt/downloadFile/844820067125562/Extended_Abstract.pdf

[@Yuēhàn24]

@@IMSAIGuy cheers thanks for the link.

[@cyberyogicowindler2448]

​@@willthecat3861 How can the holes have an effect when they are outside the copper plated parts? Or has this PCB really more than 2 layers? (Shining light through most cheap PCB antennas shows that they don't.)

[@Unpopular_0pinion]

Is that an antenna built into a pcb?

[@IMSAIGuy]

yes, it just traces on a PC board

[@Unpopular_0pinion]

@@IMSAIGuy That's lit!

[@paulsherman51]

Wonder if you could put two PC boards together, at 90-degrees to each other, receiving both H and V polarizations? Would they be phased at 0 or 90 or 180?