With that close spaced first director it looks like this is an OWA (Optimized Wideband Array) Yagi. I first saw something like this used on a 10-meter Yagi at K3LR. There are TH-cam videos with Tim talking about the design.
It seems that some gain and directivity was sacrificed to allow for the bandwidth they were trying to achieve. I’ve played with several NEC apps. It becomes apparent to see the relationship between gain and directivity versus bandwidth when manipulating the design. Very cool.
dBi stands for decibels relative to isotropic not intrinsic. Isotropic means equal radiation in all directions (impossible to realize with an actual antenna).
We did some indoor antenna testing and some of the peaks and dips corresponded with the scale of the distance to the corners of the room. We put the gear on a cart (long extension cord for power) and took it outside, aiming the antenna straight up. Much cleaner results.
Perfect for long range drone remotes, if you're using something like ardupilot/arducopter where it's connected to a laptop wirelessly. Too big for an actual traditional "remote control" or for goggles unless you've got a tripod setup and a cable run from your device to the antenna. I miss drones, it's too bad that the FAA put an end to amateur piloting of them. I've got several 915Mhz transceivers for this purpose.
The second dip at about 950 MHz (?) would probably be due to the 'parasitic radiator' (not the first director), adjacent to the driven element, accepting and radiating power. I'd already noticed that it was too short to be in the length ratio of 868/915 MHz, so perhaps its length is about 868/950 ?
Great stuff. What if on your yagi you on one side expand for lower freq. the elements or shorten them for higher freq. to get a wider range. Time to test.
i love the idea of antenna's having gain. they only have gain by having losses in some other direction. if you imaging a bulb in the centre of a ball, if it illuminates the whole surface of the ball then it like a isotropic antenna. putting a mirror behind the bulb will shine more light on parts of the ball. so at these points it would seem that the power has increased from the bulb. go behind the mirror and it will look like somebody has changed the bulb to a much less powerful one. I bought a 1GHz to 18GHz horn for about $1300 for a EMC chamber, it was made of 4 PCB's and a bit of bent metal. but it came with some very expensive paper work. 🙂
@@IMSAIGuy I like antenna design as it still has a Blackmagic element. shorted stubs, metal insulators, slot antenna's. Still can't seem to get my head around waveguides. 🙂
Viz were??? What are you, a chicken bander from the 90s?? I once laughed at an rf engineer in a meeting that said that. Everybosy else laughed when asked what he ment. Didn't know it was just a bunch of letters that stood for Voltage Standing Wave Ratio. Circa 2005. 😅😂 He also said that you can get more signal coupled through by increasing the puffs of the capacitor. I had to leave before I got fired.... 😂
These frequencies are used for LoRa like Meshtastic etc. 868 for Europe and 915 for the US
Agree, LoRa
With that close spaced first director it looks like this is an OWA (Optimized Wideband Array) Yagi. I first saw something like this used on a 10-meter Yagi at K3LR. There are TH-cam videos with Tim talking about the design.
It seems that some gain and directivity was sacrificed to allow for the bandwidth they were trying to achieve. I’ve played with several NEC apps. It becomes apparent to see the relationship between gain and directivity versus bandwidth when manipulating the design. Very cool.
dBi stands for decibels relative to isotropic not intrinsic. Isotropic means equal radiation in all directions (impossible to realize with an actual antenna).
Yes. Our host correctly said "isotropic" later, at 4:45 .
We did some indoor antenna testing and some of the peaks and dips corresponded with the scale of the distance to the corners of the room.
We put the gear on a cart (long extension cord for power) and took it outside, aiming the antenna straight up. Much cleaner results.
For great content about antennas, measuring and building, Andrew McNeil's channel is very good.
868MHz can support much of the radio equipment found in industrial settings, such as remote sensing, security and alarm systems.
Perfect for long range drone remotes, if you're using something like ardupilot/arducopter where it's connected to a laptop wirelessly. Too big for an actual traditional "remote control" or for goggles unless you've got a tripod setup and a cable run from your device to the antenna. I miss drones, it's too bad that the FAA put an end to amateur piloting of them. I've got several 915Mhz transceivers for this purpose.
Frequency range from 902 MHz to 928 MHz as an unlicensed Industrial Scientific and Medical (ISM) frequency band for North America
It's *about* the right gain to optimally feed a large dish. Keyword "about".
I think that first closely spaced director is mainly there to get a 50 ohm match.
Sold!
The second dip at about 950 MHz (?) would probably be due to the 'parasitic radiator' (not the first director), adjacent to the driven element, accepting and radiating power.
I'd already noticed that it was too short to be in the length ratio of 868/915 MHz, so perhaps its length is about 868/950 ?
Great stuff. What if on your yagi you on one side expand for lower freq. the elements or shorten them for higher freq. to get a wider range. Time to test.
You don't have an anechoic chamber?! 😁
Looks like GSM band.
LoRa or Meshtastic is more likely, which is part of the ISM band.
Wireless communication LoRa antenna. For simple uC projects
LORA antenna?
Curios what market he developed this for. Seems a little specific and small market possibilities.
i love the idea of antenna's having gain. they only have gain by having losses in some other direction. if you imaging a bulb in the centre of a ball, if it illuminates the whole surface of the ball then it like a isotropic antenna. putting a mirror behind the bulb will shine more light on parts of the ball. so at these points it would seem that the power has increased from the bulb. go behind the mirror and it will look like somebody has changed the bulb to a much less powerful one.
I bought a 1GHz to 18GHz horn for about $1300 for a EMC chamber, it was made of 4 PCB's and a bit of bent metal. but it came with some very expensive paper work. 🙂
yes, I explain it here: th-cam.com/video/FeyrQ9yyfTw/w-d-xo.htmlsi=NzS3cx1TC9Q8uftZ
@@IMSAIGuy I like antenna design as it still has a Blackmagic element. shorted stubs, metal insulators, slot antenna's. Still can't seem to get my head around waveguides. 🙂
Analogy: focusing capable flashlight going from broad beam to tight beam.
The element spacing might be strange but the feed is really weird!
It's just a matching stub; they're not that unusual.
Log periodic?
non-log aperiodic? 🙂
Quality🫱🏻🫲🏼
This board material seems not suitable for antenna application as it is too lossy.
Viz were??? What are you, a chicken bander from the 90s?? I once laughed at an rf engineer in a meeting that said that. Everybosy else laughed when asked what he ment. Didn't know it was just a bunch of letters that stood for Voltage Standing Wave Ratio. Circa 2005. 😅😂 He also said that you can get more signal coupled through by increasing the puffs of the capacitor. I had to leave before I got fired.... 😂
HAM from the 60's
if he was a chicken bander, he could have put some "SWR paste" on the connections to get a better match. 🙂
@@TheEmbeddedHobbyist How about some rf wax on the coax?