PDA

View Full Version : tin can waveguide antenna


Silas Longshot
12-16-2014, 07:22 PM
Saw this from one of my survivalist forums. Pretty neat and cheap.
http://www.turnpoint.net/wireless/cantennahowto.html

electricflyer
12-16-2014, 08:49 PM
I think John, WA8YXM has made one of those. I saw them construct it on www.amateurlogic.com.

NN5I
12-16-2014, 08:58 PM
It reminds me of a time (1958 or so) when I saw in QST an article about a vertical antenna made by soldering soda cans (maybe they were beer cans) end-to-end to form a long column. Such cans were made, in those days, of plated steel, and pretty easy to solder with a big soldering gun. Anyway, there was this tall vertical made by soldering cans end-to-end.

It was more than twenty years later that I learned that that was not what was meant by "Beverage antenna".

electricflyer
12-16-2014, 09:04 PM
You make a beverage antenna out of beer cans with JB Weld.

wa8yxm
12-17-2014, 04:59 AM
I think John, WA8YXM has made one of those. I saw them construct it on www.amateurlogic.com.

I used a coffee can. Yup. and it is episode #3 that inspired mine.

This message brought to you by said coffee can.

N3LYT
12-17-2014, 09:05 AM
Just for kicks I mounted a Linksys wireless router in the focal point of a discarded sat. tv dish man did it perk up the signal!

NN5I
12-17-2014, 10:08 AM
Just for kicks I mounted a Linksys wireless router in the focal point of a discarded sat. tv dish man did it perk up the signal!

I did that too, a couple years ago. It worked extremely well. Now I use 18-element Yagis when I want a lot of gain. They're pretty inexpensive on eBay. The dish was possibly a bit better for gain, but the Yagis are not quite so, um, ungainly, and also easier to aim. Besides, I don't have to leave the router out in the rain.

N3LYT
12-17-2014, 06:28 PM
Yeah strictly an experiment I saw a site with a Yagi with a built in TX amp. Don’t have a clue if it’s any good but it had potential. Found it-- http://www.amazon.com/NextG-USB-Yagi-Range-antenna-2200mW/dp/B0044D7J1W/ref=sr_1_4?ie=UTF8&qid=1383027828&sr=8-4&keywords=long+range+wifi That should work right through the window.

electricflyer
12-17-2014, 08:01 PM
I got three different WIFI antennas on Ebay. A directional 14 element Yagi with 20dbi gain (so they say), a omnidirectional with 15dbi gain and a magmount (weak magnet) with 20dbi gain. Each was less than $8. Carl must have at least a 25dbi gain with 18 elements. Now I am anticipating a bidirectional amp at least 2W's. They go for $25 to $60. Several guys in the local ham club are playing with mesh net

N3LYT
12-18-2014, 08:02 AM
All though it's easy to build a gain antenna for 2.4 gigs the feed losses are not so easy to deal with. the one I found on Amazon if it's any good is one way around that is by using a USB feed with the amps inside the antenna. If I happen to fall over a hundred bucks I may just buy one.

wa8yxm
12-18-2014, 08:15 AM
Just for kicks I mounted a Linksys wireless router in the focal point of a discarded sat. tv dish man did it perk up the signal!


Estimated gain for an 18 dish is around 20dB as I recall. However take that with a large grain of sodium chloride as I did that math a long, long time ago and thus recall may be rusty.

N3LYT
12-18-2014, 07:11 PM
Yeah there are a lot of variables with the dish setup but it sure was a huge difference in the signal. The Linksys has two antennas so it was a bit hard to get both in the focal point but I sure can see where a dish would make a great WiFi antenna and it does not have to be huge. I think if I really wanted it to work a single antenna and a weather proof box might be a workable setup. Some of the Linksys wireless used Linux software and DDwrite programming they could easily be used as client's

NN5I
12-18-2014, 07:52 PM
Yeah there are a lot of variables with the dish setup but it sure was a huge difference in the signal. The Linksys has two antennas so it was a bit hard to get both in the focal point but I sure can see where a dish would make a great WiFi antenna and it does not have to be huge. I think if I really wanted it to work a single antenna and a weather proof box might be a workable setup. Some of the Linksys wireless used Linux software and DDwrite programming they could easily be used as client's

The Linksys routers, typically WRT54G or WRT54GS but also many others, work perfectly well with one antenna (use a dummy load on the other antenna connector because at startup it may try to transmit through each antenna). DD-WRT firmware also works exceedingly well and can be configured as a client, a repeater, a client bridge, a repeater bridge, or any of several other ways, and it's free. By the way, the DD in DD-WRT is for the city of Dresden, Germany, where DD-WRT was developed; and the WRT stands for Wireless Router and comes from the model numbers of Linksys wireless routers. DD-WRT was originally developed for the WRT54G series of routers.

wa8yxm
12-20-2014, 05:24 AM
That is one of the things I like about my Cantenna

The active electronics hooked to it are right there but they are NOT USB they are Ethernet so instead of 3 meters lead limit its more like 100 meters (I only have a bit under 100 feet of Cat-5 cable though)

N3LYT
12-20-2014, 09:36 AM
That is one of the things I like about my Cantenna

The active electronics hooked to it are right there but they are NOT USB they are Ethernet so instead of 3 meters lead limit its more like 100 meters (I only have a bit under 100 feet of Cat-5 cable though)

True but it's not feed line that's where the problem comes in. The feed line is very short to the device then ethernet cable beyond. The Yagi thing I was talking about picks up power from the computer via the USB and the TX/RX amps are right at the feed point. The ethernet setup would however allow you to use more than one computer if properly configured. I think a cantenna at the focal point of a dish would be a killer antenna

W7JZE
12-22-2014, 10:06 PM
:confused:Yeah strictly an experiment I saw a site with a Yagi with a built in TX amp. Donít have a clue if itís any good but it had potential. Found it-- http://www.amazon.com/NextG-USB-Yagi-Range-antenna-2200mW/dp/B0044D7J1W/ref=sr_1_4?ie=UTF8&qid=1383027828&sr=8-4&keywords=long+range+wifi That should work right through the window.

That looks like a nice, compact, high-gain setup... But I have a question. The only cable I see running to the powered antenna is a USB cable. I get that the USB cable supplies to power to the embedded antenna RF amps. But, where does the amplified RF signal GO? Surely not down the USB cable.

Is there a second RF / coax cable hooked to the antenna that is just not shown in the picture?

The current external WiFi (not powered) antenna that I have only has a thin RF / coax cable coming out of it that I plug into the WiFi card in my computer.

I think I'm missing something obvious here :confused:.

NN5I
12-23-2014, 01:11 AM
I have a question. The only cable I see running to the powered antenna is a USB cable. I get that the USB cable supplies to power to the embedded antenna RF amps. But, where does the amplified RF signal GO? Surely not down the USB cable.

You're missing something, but it's not particularly obvious, so don't worry.

There is no amplified RF signal. Inside the box mounted on the antenna is, essentially, a WiFi client device, or router, that receives and transmits the WiFi signals and provides Internet access to a PC through the USB cable (it is powered through USB, too). Most PC operating system versions can connect through USB instead of through Ethernet, but there are some that can't. That's why they specify operating system compatibility. Click the "15 answered questions" link in the ad for additional insights.

W7JZE
12-23-2014, 09:41 AM
You're missing something, but it's not particularly obvious, so don't worry.

There is no amplified RF signal. Inside the box mounted on the antenna is, essentially, a WiFi client device, or router, that receives and transmits the WiFi signals and provides Internet access to a PC through the USB cable (it is powered through USB, too). Most PC operating system versions can connect through USB instead of through Ethernet, but there are some that can't. That's why they specify operating system compatibility. Click the "15 answered questions" link in the ad for additional insights.

AHhhh... Got it. Many thanks Carl. That makes sense.

(And happy eve of Christmas Eve to those that celebrate :-)