Fantastic video! I only wish I had some of your test equipment! I have gear but not for Gigahertz-land! I have been investigating can-tennas however. It is my understanding that straight sidewalls, not ridged as in food cans, will increase efficiency. Now, off to see how this does in the parabolic dish!
Hi Dave, Well, them beans are good for the heart, ya know..LOL My electronics lab is a separate building on my property and is just at the hairy edge of what my wifi can deliver. The Chinese have repeaters for wifi on epay for under $20 but not sure they are worth the effort. I considered buying or perhaps building a set of yagis but you have encouraged me with your EXCELLENT work/video to build something. Of course not having wifi in the lab probably saves me a lot of wasted time watching youtube..LOL But, to be able to look for technical docs and parts while working does save time.. Again, thanks for the time you invest making thee great videos. 73, Glenn WA4AOS
Glenn - always good to hear from you. I do not know about the repeaters but once I did have two parabolic dishes between my house and my mother-in-laws house for Internet and security camera purposes. Now I use EnGenius access points - I think they are ENH202 - much smaller and sleek and they work great. I bet they are just what you need between your house and lab. The yagis that I have purchased from China are junk - the "cantenna" out performs them many times and are very directional. I actually hate computers as the damn thing takes up valuable real estate in my shop (which is tiny) but I do need it as you mentioned for technical documents and the such.
Loved this video…I’d like to make one for 1296 MHz band. I wonder what effect grounding the sleeve of the connector or a small counterpoise would have on the match…
The big question will be if chopping the tuning poles will result in the same results. That protruding part outside of the can is an inverse antenna. Cutting it will potentially destroy any tuning you got from them, as the protrusion that is collecting signals and mirroring them inside, is no longer acting as a notch filter.
Nice work you did there. I've been curious about these antennas also but just haven't had the time to do what you did here. Thanks much! It would be great if you could pass some starting point measurements along to us. It would be greatly appreciated!
I have built a number of these "cantenna" type antennas over the years and through experimentation, I have come to the general same conclusions of the article that was laying on my work bench, "Horns for the Holidays" by Joel Harrison, W5ZN. He did a nice job of documenting his project and his article is on the Internet. Go to "W5ZN.ORG". In my case, the tuning stub that was directly in line with the driven element was too sensitive and did not make things better so I offset them at 90 degrees and about 135 degrees. As I mentioned in the video, we all seem to discover something of value about these devices both as an antenna and a feed horn to illuminate a parabolic dish. I hope to get to the dish mount soon and am anxious to see how that turns out. Naturally, I will have to make some relative measurements at a much greater distance to test the parabolic antenna - Thanks for your comments.
Also adding... The diameter and inner flat surface volume, as well as the direct reflection from the back plane of the can, are what makes these difficult to tune. You have two combined principals you are fighting in one device. Unfortunately, like you indicate, we all need these tools to honestly tune these things. This, making DIY, severely limited, since computers don't relay actual signal strength, but a rough estimate that is honestly irrelevant for testing. I can get a -80 db signal and have a solid connection, or absolutely no functional connection, through the same measured antenna. By adjusting it, you can go completely past the tuned spot and the computer will never even register it and sometimes that will be just as non-functional too. The only true "test", is a long distance connection, with a ping and a persistent download stream. I have had connections down to -40 db, which had pings in the 2000-4000ms response times and could only provide bursts of fast data, before the signal became saturated and literally knocked out the wifi chip or they just throttle down to a 0.01 Kbps speed before the signal ultimately drops. But it's a solid signal still, just not a functional signal. It's like trying to hear your guitar playing with feedback. Yes, that note is 40x louder, but it's not the note you are currently playing anymore.
Very cool idea. I wonder how much the tuning legs effect directionality if at all. Thanks for all the help w/ locating a SWR meter for 2.44ghz - to make good antennas you really need "Eyes" (otherwise we're just guessing! 27mhz is so much more forgiving ) 73 from n. idaho
It would have been more interesting to detune the antenna in the can to get a SWR of around 1.5 to 2.0 (still 95% - 89% transmitted power) to see how much that effected the received signal. I suspect that you will not see much difference, meaning it's the directionality of the can thats bringing the "gain" up. Love your man-cave & gear!
4" is too big. The ideal size range is between 80mm and 90mm. Use big sauce cans, 3-1/4, that comes to 82.5mm. Then, the hole in the can needs to be 2.49" from the base of the can. I wish I had equipment like yours.
+UNITED POLICE STATES OF AMERICA I don't doubt that you are right but the reason I used the 4" can is so it will fit properly inside the thin wall PVC - I would have to go to 3" for the next size down in PVC. Thanks.
There is nothing wrong with cladding pvc or other materials like cardboard in aluminium tape... or aluminium foil if you must. You can make any size you like and see what works best... Would be great to get test results on all the myths and assumptions out there on cantenna's biquads, double biquads and helical antenna's... With a equipement setup like that...man, would be great to see some stuff debunked or "set in stone" so to speak...
I haven't worked with any 2.4G antennas lately. I used home brew antennas for a long time to communicate wifi to my mother-in-laws house but about a year ago, I installed store-bought 5 GHz antennas and they are so much better. I still have a nice stash of parabolic reflectors but just haven't messed with them lately. I do have several videos on the 2.4 GHz antennas that you may not have seen that does document, as best I can, their performance. Thanks for your comment.
it looks as if you space the driven element further from the base of the can with the longer cans. How far from the base with a 6.5 inch long can, please?
Hi Nick, I don't have an actual mathematical formula for these dimensions so I would put it at about the same place, approximately 1/2 wavelength from the bottom whether it be a 6 inch or 6.5 inch can. I plan on a video tonight showing a book I take some of these dimensions from and hope it will help answer some questions.
+Shannon Brooks From my experience, a 4 inch diameter (about 10 mm) can works well for 2.4 GHz. I put the screws at the same distance from the bottom of the can as the feed point is from the bottom of the can.You just have to play with the lengths of the screws as I mention in the video as some are more important than others in changing the reflected power. Watch the video again and I think I mention all the important dimensions. If you want to start with my adjustments, you can stop the video at some convenient point and using the diameter of the can as 4 inches, make relative measurements on the computer screen of the lengths of the screws and tweak from there. Hope this helps.
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This is fascinating, even if you did deafen me with banging the cans around! Thanks for the information.
Fantastic video! I only wish I had some of your test equipment! I have gear but not for Gigahertz-land! I have been investigating can-tennas however. It is my understanding that straight sidewalls, not ridged as in food cans, will increase efficiency. Now, off to see how this does in the parabolic dish!
You got nice toys there.. made me drool..
amazing! just wowed at your efforts mate
Hi Dave,
Well, them beans are good for the heart, ya know..LOL
My electronics lab is a separate building on my property and is just at the hairy edge of what my wifi can deliver. The Chinese have repeaters for wifi on epay for under $20 but not sure they are worth the effort. I considered buying or perhaps building a set of yagis but you have encouraged me with your EXCELLENT work/video to build something.
Of course not having wifi in the lab probably saves me a lot of wasted time watching youtube..LOL But, to be able to look for technical docs and parts while working does save time..
Again, thanks for the time you invest making thee great videos.
73,
Glenn WA4AOS
Glenn - always good to hear from you. I do not know about the repeaters but once I did have two parabolic dishes between my house and my mother-in-laws house for Internet and security camera purposes. Now I use EnGenius access points - I think they are ENH202 - much smaller and sleek and they work great. I bet they are just what you need between your house and lab. The yagis that I have purchased from China are junk - the "cantenna" out performs them many times and are very directional. I actually hate computers as the damn thing takes up valuable real estate in my shop (which is tiny) but I do need it as you mentioned for technical documents and the such.
Loved this video…I’d like to make one for 1296 MHz band. I wonder what effect grounding the sleeve of the connector or a small counterpoise would have on the match…
Take a look at these two I posted not long ago.
ruclips.net/video/SDLm1N10fTI/видео.html
ruclips.net/video/KLhxggZbsVc/видео.html
The big question will be if chopping the tuning poles will result in the same results. That protruding part outside of the can is an inverse antenna. Cutting it will potentially destroy any tuning you got from them, as the protrusion that is collecting signals and mirroring them inside, is no longer acting as a notch filter.
Nice work you did there. I've been curious about these antennas also but just haven't had the time to do what you did here. Thanks much! It would be great if you could pass some starting point measurements along to us. It would be greatly appreciated!
I have built a number of these "cantenna" type antennas over the years and through experimentation, I have come to the general same conclusions of the article that was laying on my work bench, "Horns for the Holidays" by Joel Harrison, W5ZN. He did a nice job of documenting his project and his article is on the Internet. Go to "W5ZN.ORG". In my case, the tuning stub that was directly in line with the driven element was too sensitive and did not make things better so I offset them at 90 degrees and about 135 degrees. As I mentioned in the video, we all seem to discover something of value about these devices both as an antenna and a feed horn to illuminate a parabolic dish. I hope to get to the dish mount soon and am anxious to see how that turns out. Naturally, I will have to make some relative measurements at a much greater distance to test the parabolic antenna - Thanks for your comments.
ElPaso TubeAmps
Thanks much for the link...A gold mine of info indeed. It is very appreciated..!
Also adding... The diameter and inner flat surface volume, as well as the direct reflection from the back plane of the can, are what makes these difficult to tune. You have two combined principals you are fighting in one device. Unfortunately, like you indicate, we all need these tools to honestly tune these things. This, making DIY, severely limited, since computers don't relay actual signal strength, but a rough estimate that is honestly irrelevant for testing. I can get a -80 db signal and have a solid connection, or absolutely no functional connection, through the same measured antenna. By adjusting it, you can go completely past the tuned spot and the computer will never even register it and sometimes that will be just as non-functional too. The only true "test", is a long distance connection, with a ping and a persistent download stream.
I have had connections down to -40 db, which had pings in the 2000-4000ms response times and could only provide bursts of fast data, before the signal became saturated and literally knocked out the wifi chip or they just throttle down to a 0.01 Kbps speed before the signal ultimately drops. But it's a solid signal still, just not a functional signal. It's like trying to hear your guitar playing with feedback. Yes, that note is 40x louder, but it's not the note you are currently playing anymore.
Very cool idea. I wonder how much the tuning legs effect directionality if at all.
Thanks for all the help w/ locating a SWR meter for 2.44ghz - to make good antennas you really need "Eyes" (otherwise we're just guessing! 27mhz is so much more forgiving )
73 from n. idaho
very nice!! keep up the great vids
It would have been more interesting to detune the antenna in the can to get a SWR of around 1.5 to 2.0 (still 95% - 89% transmitted power) to see how much that effected the received signal. I suspect that you will not see much difference, meaning it's the directionality of the can thats bringing the "gain" up.
Love your man-cave & gear!
Awesome work thanks for posting
4" is too big. The ideal size range is between 80mm and 90mm. Use big sauce cans, 3-1/4, that comes to 82.5mm. Then, the hole in the can needs to be 2.49" from the base of the can. I wish I had equipment like yours.
+UNITED POLICE STATES OF AMERICA I don't doubt that you are right but the reason I used the 4" can is so it will fit properly inside the thin wall PVC - I would have to go to 3" for the next size down in PVC. Thanks.
There is nothing wrong with cladding pvc or other materials like cardboard in aluminium tape... or aluminium foil if you must. You can make any size you like and see what works best... Would be great to get test results on all the myths and assumptions out there on cantenna's biquads, double biquads and helical antenna's... With a equipement setup like that...man, would be great to see some stuff debunked or "set in stone" so to speak...
I haven't worked with any 2.4G antennas lately. I used home brew antennas for a long time to communicate wifi to my mother-in-laws house but about a year ago, I installed store-bought 5 GHz antennas and they are so much better. I still have a nice stash of parabolic reflectors but just haven't messed with them lately. I do have several videos on the 2.4 GHz antennas that you may not have seen that does document, as best I can, their performance. Thanks for your comment.
it looks as if you space the driven element further from the base of the can with the longer cans. How far from the base with a 6.5 inch long can, please?
Hi Nick,
I don't have an actual mathematical formula for these dimensions so I would put it at about the same place, approximately 1/2 wavelength from the bottom whether it be a 6 inch or 6.5 inch can. I plan on a video tonight showing a book I take some of these dimensions from and hope it will help answer some questions.
Would it be a 20 gain overall if were -10 db to 10 db?
Yes, if you got 10 dB gain from the feed horn and 10 dB gain from the parabolic dish, it would be 20 dB gain or a gain factor of 100.
dose the plastic coating make a difference?
How to check gain of can antenna using Spectrum Analyser ?
What are the can measurments ? What are the screw's in the can measurment's ? HELP !
+Shannon Brooks From my experience, a 4 inch diameter (about 10 mm) can works well for 2.4 GHz. I put the screws at the same distance from the bottom of the can as the feed point is from the bottom of the can.You just have to play with the lengths of the screws as I mention in the video as some are more important than others in changing the reflected power. Watch the video again and I think I mention all the important dimensions. If you want to start with my adjustments, you can stop the video at some convenient point and using the diameter of the can as 4 inches, make relative measurements on the computer screen of the lengths of the screws and tweak from there. Hope this helps.
Thank you ElPaso........Quick responce, and willing too help. Wish more ppl was like that...
What tin can are you using
If I remember correctly, it is a 46 ounce, Bush beans can.
Do you have a measures?
3 db gain is nothing to sneeze at. 10 db is fantastic.
Does this work?
watch where your pointing that thing, nice
The conclusion is absent. A VNA will show the result instantly.