My XBee long range setup - 1.5 miles with yagi antenna

zepperik

The rubber ducky antenna available for sale from Parallax (#32410) has a very limited range when attached to an XBee Pro SB3 900MHz module. After a few tests, I found it very difficult to communicate further than 1/4 of mile. On the Parallax page for the module, it claims up to 9 miles with a dipole antenna and 28 miles with a high gain antenna. So I started trying to find an appropriate antenna. After a lot of research without finding a definitive answer online, I went ahead and bought a yagi antenna from digikey: OSCAR3A/X/FMEM/S/S/19-ND. Here's the datasheet for it: https://www.siretta.co.uk/download.php?id=709&cmd=view. It sort of made me nervous because it claims a max power rating of 200W so I wasn't sure what would happen with 0.25W driving it. Also I needed a Female FME to RPSMA Male cable. The antenna is about 6 by 24 inches in size.

So my setup was 2 XBee modules with 2 antennas about 4 feet off the ground. One powered via walworth supply and the other via USB. I haven't full tested the range on this setup since I found it suitable to my application, but I found it reaching 1.5 miles without any problem and without ideal conditions. Even with the antenna facing backwards and invisible below a hill, I could communicate with it over a mile away. At 1.5 miles, with one antenna turned backwards, it still had only a 10% packet loss. I'm guessing its reasonable to expect 2 to 3 miles line-of-sight.

So I hope this post helps someone googling for hours like I was. I'll update it if I ever learn more or do more range tests. I wish Parallax would sell a directional antenna or at least give a recommendation, because your application space opens up greatly with 1+ mile unlicensed radio communication.

Publison

Thanks for the update! With that yagi I would expect more than 3 miles LOS.

Ken Gracey

This helps me more than you know. I'm currently working on a robotic boat project that I'm going to deploy in Lake Tahoe. My plan (prior to now) had been to use the 900 HP XBees with the antenna that we sell at Parallax. I'll be sending this boat out on the lake to collect some turbidity samples at different GPS waypoints. It's possible that it could be 10 miles from me at times. I'd like to be able to transmit the location back to me should it need to be retrieved for some reason. I'll probably have to use SMS backup.

As for the Parallax antenna only being suitable for this short range, I'll look into getting the Digi-Key antenna you identified in stock.

Also, can you tell me where you got the Female FME to RPSMA Male cable. What part number?

Thanks,

Ken Gracey

Beau Schwabe

It's not Xbee, but I have been using a point to point WiFi at a distance of 15 miles. The endpoints are about $50 a piece (you need at least two of them) but as long as you supply power (12V), each unit "think's" it is a direct Ethernet cable connection even though they are 15 miles apart. I thought of something similar over lake Michigan as far as a remote robotic fishing boat, and since it's Ethernet, video feedback would be a cinch.

Something like this ... https://www.amazon.com/dp/B00HXT8FFI/ref=psdc_1194486_t1_B004EGI3CI#Ask

Phil Pilgrim (PhiPi)

Ken,

I see you're using the Blue Robotics thrusters. They're great! -- as long as there's no floating seaweed, like there is around here. 'Should be perfect for Lake Tahoe.

-Phil

RS_Jim

Hey ken,
Sounds like a really cool project. Don't forget about curvature of the earth effect on LOS. If I remember correctly from my flying days, about 6 feet every 16 miles.
Edit, further research says my memory is probably incorrect. Solution, take pair of field glasses up on a hill until you can see opposite shore. Then you will have enough range for coms. Search boat won't need that range as you are moving to a gps coordinate.
Jim

WBA Consulting

Zepperik, thanks so much for posting this. Many times I consider posting tidbits of a project I have come across that became a major challenge in case someone else faces the same challenge. Although I don't have any open projects needing this type of range, I have had a couple projects that could have been done without WiFi had I used this solution.

kwinn

Ken Gracey wrote: »

This helps me more than you know. I'm currently working on a robotic boat project that I'm going to deploy in Lake Tahoe. My plan (prior to now) had been to use the 900 HP XBees with the antenna that we sell at Parallax. I'll be sending this boat out on the lake to collect some turbidity samples at different GPS waypoints. It's possible that it could be 10 miles from me at times. I'd like to be able to transmit the location back to me should it need to be retrieved for some reason. I'll probably have to use SMS backup.

As for the Parallax antenna only being suitable for this short range, I'll look into getting the Digi-Key antenna you identified in stock.

Also, can you tell me where you got the Female FME to RPSMA Male cable. What part number?

Thanks,

Ken Gracey

Don't forget that yagi antennas are directional so they will need to be aligned. Simple enough on land, not so easy on water, although not terribly difficult.

WBA Consulting

kwinn wrote: »

Don't forget that yagi antennas are directional so they will need to be aligned. Simple enough on land, not so easy on water, although not terribly difficult.

Good point. Since the craft has a GPS though, it's a simple matter of calculating the bearing to "home" coordinates and compensating for the current heading of the craft. Mount the Yagi with one of Parallax's new fancy servos and voila.
Here's my handheld GPS that calculates bearing to the target location using great circle math.
http://forums.parallax.com/discussion/133806/propeller-based-handheld-gps-with-full-code

zepperik

Ken,

I got the cables on Amazon: https://www.amazon.com/gp/product/B01F18QWQ6/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

I would hope there is some setup that can get you 10 miles. I'm not sure if these 28 mile claims are just based off mathematical calculations or not. I spent over 20 hours researching this and found no claims with details on what kind of setup can go more than a few miles. I got sort of obsessed after watching Stranger Things and wondering why Walkie-Talkies can go so far but nothing digital can. It seems there are FCC regulations on using Analog frequencies for digital data. There are actually digital handheld radios with serial ports made by Motorolla but they are pricey and I think you need an FCC license.

Maybe you can setup buoys with XBees setup as routers - although I'm not sure what that antenna needs to look like if you need to to talk in two directions.

Publison

Here is the one DIGI carries, looks to be the same as linked to:

https://www.digi.com/products/models/a09-y11nf

sidecar-racer

Neat project, a thought is Yagis are great for gain, but, as noted earlier uni-directional. If boat's isn't oriented right = no signal. With the very high frequency you might consider a vertical antenna. They can be designed for gain when multiple wavelengths long.

sidecar-racer

Now that I think about it, boat size need be considered. Commercial verticals are pretty long and heavy. Also if you use Yagi on shore, needs to be vertically oriented.

sidecar-racer

Found what I was looking for: collinear vertical antenna

Phil Pilgrim (PhiPi)

It's really easy to build a yagi antenna from PVC pipe and welding rod. Here's one I built many years ago to operate at 433 MHz, IIRC:



Note that it uses a half-folded dipole as the active element. This will match with a 75-ohm source and coax.

There are many places on the web that you can use to get the element lengths and spacings. No need to buy a commercial antenna -- especially at the small sizes required by UHF.

-Phil