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Luka
EVDO User
Joined: 07 Mar 2007
Posts: 93
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 Posted: Mon Mar 12, 2007 12:24 am Post subject: Unconventional reception methods. ie "dish" for do |
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Has anyone used "unconventional" methods of trying to obtain a better signal ?
Since the U720 is a "dongle" type antenna, that plugs into a usb port, has anyone tried something like using an old "dish network" or "rca" satellite dish ? (The little grey ones.)
Put the dongle in place of the LNB horn. Then run a USB extension cable from that to your usb port on your computer.
If so, does it make any difference ? |
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Luka
EVDO User
Joined: 07 Mar 2007
Posts: 93
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| Posted: Thu Mar 22, 2007 10:10 pm Post subject: Re: Unconventional reception methods. ie "dish" fo |
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horsessmellfunny
EVDO Junkie
Joined: 03 Feb 2006
Posts: 356
Location: Castle Rock, CO
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| Posted: Thu Mar 22, 2007 10:13 pm Post subject: |
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Unfortunately for PCS cellular you need something tuned to the right frequency, 800 - 1900mhz. I used an old Dish Network satellite and a cantenna I made (which was tuned to 2.4 ghz of course) and was able to move around my property with a 10 mile LOS distance on my wireless network. That was entirely different then what you are looking for. you can make a tuned antenna for the PCS frequency, but its not as easy as you may think. Google search it, you will find one you can make out of a hangar and a cardboard tube. Your best bet is to jut buy an antenna built by the professionals!
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n6gn
EVDO Junkie
Joined: 22 Aug 2006
Posts: 439
Location: Northern California
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| Posted: Thu Mar 22, 2007 10:14 pm Post subject: Re: Unconventional reception methods. ie "dish" fo |
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Would you like to see my $.01, 10 dB gain antenna using the U720?
Hint: it uses a scrap cardboard box and the $.01 of aluminum foil.
n6gn |
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Luka
EVDO User
Joined: 07 Mar 2007
Posts: 93
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| Posted: Thu Mar 22, 2007 10:32 pm Post subject: |
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| horsessmellfunny wrote: | | Unfortunately for PCS cellular you need something tuned to the right frequency, 800 - 1900mhz. I used an old Dish Network satellite and a cantenna I made (which was tuned to 2.4 ghz of course) and was able to move around my property with a 10 mile LOS distance on my wireless network. That was entirely different then what you are looking for. you can make a tuned antenna for the PCS frequency, but its not as easy as you may think. Google search it, you will find one you can make out of a hangar and a cardboard tube. Your best bet is to jut buy an antenna built by the professionals! |
Thank you horsey.
I fully intend to buy the real thing. As soon as I can afford it.
I just like to dink with things and see what else can be done.
As for the dish idea...
In my idea, I am not 'building' an antenna.
The u720 IS the antenna.
It is a USB dongle. It is fairly close to the same size as my WiFi usb dongle. And I know that putting the WiFi dongle onto anything that focuses the signal on the dongle... Increases the WiFi signal strength.
Again... The U720 USB dongle IS the antenna. I am NOT building an antenna.
The ONLY difference from having it plugged into the laptop... The ONLY thing you are doing... Is putting it in place of the module on the dish. And running a USB cable from the dongle to the laptop or tabletop PC.
That dish will focus any available signal, onto the U720, when the U720 is attached in place of the satellite receptor.
That is the only function of the dish. Gathering more signal, and focusing it back, onto the real antenna.
I would think that it's a no-brainer. It should help with the signal.
Instead of, what ?... all of 1/2" or 3/4" of antenna on the dongle itself trying to catch whatever signal happens to wander on by...
Instead of gathering in all of 1/2" to 3/4" of signal...
You have 18 inches to two feet of parabolic dish, gathering the signal and focusing it on that 1/2" of antenna.
I am on a fixed income. I cannot yet afford to try this myself. But when I can, you can be assured, I will.
I already have the old dish sitting here, ready. When I can afford the U720, I wil buy one, and the race will be ON !!!
I was just curious if anyone else had tried anything similar, yet. |
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Luka
EVDO User
Joined: 07 Mar 2007
Posts: 93
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| Posted: Thu Mar 22, 2007 10:33 pm Post subject: Re: Unconventional reception methods. ie "dish" fo |
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| n6gn wrote: |
Would you like to see my $.01, 10 dB gain antenna using the U720?
Hint: it uses a scrap cardboard box and the $.01 of aluminum foil.
n6gn |
Absolutely !! Post up the pics !!
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n6gn
EVDO Junkie
Joined: 22 Aug 2006
Posts: 439
Location: Northern California
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| Posted: Thu Mar 22, 2007 10:38 pm Post subject: Re: Unconventional reception methods. ie "dish" fo |
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| Luka wrote: | | n6gn wrote: |
Would you like to see my $.01, 10 dB gain antenna using the U720?
Hint: it uses a scrap cardboard box and the $.01 of aluminum foil.
n6gn |
Absolutely !! Post up the pics !!
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I was afraid you were going to say that! 
OK, give me a couple of days.
BTW, it does work as you proposed, the 720 antenna is the antenna and the cardboard box & aluminum foil serves to mirror energy that would have gone other directions into the preferred one. It's called a 'corner reflector' antenna and is actually quite common.
While DBS dishes will work the same way, theywould really like to have an additional reflector between the U720's antenna and the direction of interest in order to work properly. This isn't hard but it does add complexity. The corner reflector version doesn't need this.
I'll see if I can get a suitable picture for you...
n6gn |
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Luka
EVDO User
Joined: 07 Mar 2007
Posts: 93
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| Posted: Thu Mar 22, 2007 10:42 pm Post subject: Re: Unconventional reception methods. ie "dish" fo |
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| n6gn wrote: |
I was afraid you were going to say that!
OK, give me a couple of days.
BTW, it does work as you proposed, the 720 antenna is the antenna and the cardboard box & aluminum foil serves to mirror energy that would have gone other directions into the preferred one. It's called a 'corner reflector' antenna and is actually quite common.
While DBS dishes will work the same way, theywould really like to have an additional reflector between the U720's antenna and the direction of interest in order to work properly. This isn't hard but it does add complexity. The corner reflector version doesn't need this.
I'll see if I can get a suitable picture for you...
n6gn |
I think I've seen a corner antenna before.
Still... Looking forward to the pics.
Ok, an additional relector between...
You mean, as in an aluminum foil patch between the U720, and the signal ? That way, the only signal hitting the U720 comes from the dish itself ?
Or does the patch have to also be parabolic, and toss the signal back at the U720 again...
??? |
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Luka
EVDO User
Joined: 07 Mar 2007
Posts: 93
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| Posted: Thu Mar 22, 2007 11:07 pm Post subject: Re: Unconventional reception methods. ie "dish" fo |
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You mean something like this ?
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n6gn
EVDO Junkie
Joined: 22 Aug 2006
Posts: 439
Location: Northern California
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| Posted: Thu Mar 22, 2007 11:12 pm Post subject: Re: Unconventional reception methods. ie "dish" fo |
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| Luka wrote: | You mean something like this ?
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Yes
When you make the reflector behind the feed curved you may no longer have what is called a "prime focus feed". Instead you may have a Cassegrain, Gregorian (or some other name I can't spell) antenna. Note all this is the same as for reflecting telescopes for astronomy - they're antennas too, just a lot shorter wavelength.
People do make the reflector curved sometimes when it's prime focus but if the curved part is doing anything interesting it's no longer prime focus.
Hang on a bit, I'm trying to take some pictures.
n6gn |
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horsessmellfunny
EVDO Junkie
Joined: 03 Feb 2006
Posts: 356
Location: Castle Rock, CO
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| Posted: Thu Mar 22, 2007 11:23 pm Post subject: |
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Ah yes, now I understand what you are trying to do a bit better. I did the same thing with the cantenna, (I even used the actual access point), problem with the access point was I couldnt get a nice direction on it. The LNB (which is the box dealy at the tip of the dish that picks up and transmits the signal) is what you are doing, but with your USB dongle. Give it a shot, the worst thing you can do is iradiate your neighbor :). If I still had my dish I would try something similar, but I cant. I used to dink around a lot myself with satellite dishses and LOS, but now that I live in a populated area, and dont really have much use for it, its kind of pointless. Good luck with n6gn's set up! Post pics and gain achieved!
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n6gn
EVDO Junkie
Joined: 22 Aug 2006
Posts: 439
Location: Northern California
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| Posted: Fri Mar 23, 2007 1:42 am Post subject: Re: Unconventional reception methods. ie "dish" fo |
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| Luka wrote: |
Still... Looking forward to the pics.
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OK, It's a bit crude but here you go.
http://www.sonic.net/~n6gn/corner.pdf
n6gn |
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jackrodgers
EVDO Addict
Joined: 23 Mar 2006
Posts: 1131
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| Posted: Fri Mar 23, 2007 5:37 am Post subject: Re: Unconventional reception methods. ie "dish" fo |
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Suggestion: use an inexpensive ball tripod head so you can pan and tilte and then lock the unit in that position. This would give you 180 right and left and 180 up and down. |
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n6gn
EVDO Junkie
Joined: 22 Aug 2006
Posts: 439
Location: Northern California
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| Posted: Fri Mar 23, 2007 9:21 am Post subject: Re: Unconventional reception methods. ie "dish" fo |
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| jackrodgers wrote: |
Suggestion: use an inexpensive ball tripod head so you can pan and tilte and then lock the unit in that position. This would give you 180 right and left and 180 up and down. |
Yes that would add to the versatility but think what it would do to the project budget !! 
In reality, azimuth is probably the only pointing ability one needs and it's pretty easy to rotate the box.
BTW, I didn't mention it in the text but the unity gain beamwidth is about 70 degrees. That means if you don't point it within 35 degrees of the correct direction, this antenna has negative gain (loss).
n6gn |
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Three60guy
EVDO User
Joined: 21 Feb 2007
Posts: 73
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| Posted: Fri Mar 23, 2007 10:05 am Post subject: |
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Is this antenna rated for 100 mph wind loading? hmmmmmmm
Seriously, nice to see work like this being done here.
Cheers |
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