Skipoint0
Posts: 14
Joined: Mon Jan 12, 2015 9:33 pm

Long Range Transmitters/Recievers

Wed Jul 15, 2015 8:16 pm

I'm looking for some advice on a transmitter/receiver. Requirements are:
-Raspberry Pi B+ 1 and higher
-USB (wired connector, don't want a chip sticking out)
-long distance, preferably 1/2 mile or .8 kilometers (remote mountain region)
-not too bulky, it'll be placed on a mobile snowmaking unit and an indoor base station away from the snow gun.

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jbeale
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Re: Long Range Transmitters/Recievers

Wed Jul 15, 2015 8:36 pm

If you have line-of sight to your remote unit, and are willing to use a high-gain (directional) antenna at your base station that you can aim at the remote, then I think you can still use wifi: https://en.wikipedia.org/wiki/Long-range_Wi-Fi

On the remote end maybe a simple small unit is still OK. This is the best one of the few I've tried with the R-Pi (I have not used it long-range or outdoors though): http://www.tp-link.com/en/products/deta ... N822N.html I don't know as it's water-resistant, works below freezing or anything like that.

It sounds like a very demanding environment and for reliability you may have to use real industrial radios designed for harsh environments, would cost a lot more than consumer stuff of course.

Skipoint0
Posts: 14
Joined: Mon Jan 12, 2015 9:33 pm

Re: Long Range Transmitters/Recievers

Wed Jul 15, 2015 9:27 pm

jbeale wrote:If you have line-of sight to your remote unit, and are willing to use a high-gain (directional) antenna at your base station that you can aim at the remote, then I think you can still use wifi: https://en.wikipedia.org/wiki/Long-range_Wi-Fi

On the remote end maybe a simple small unit is still OK. This is the best one of the few I've tried with the R-Pi (I have not used it long-range or outdoors though): http://www.tp-link.com/en/products/deta ... N822N.html I don't know as it's water-resistant, works below freezing or anything like that.

It sounds like a very demanding environment and for reliability you may have to use real industrial radios designed for harsh environments, would cost a lot more than consumer stuff of course.
Very demanding. Most of the people I've talked to in this line of work (snowmaking tech) that have military experience say the army was like a stroll in the park. check out the Killington Mountain, Vermont, USA interview on YouTube to see what its like. as a matter of transmitters, I most likely will have to use radio because in real-world applications, the receiver can be 10,000-20,000 feet away from base in a highly mountainous region with a ski slope 6,000 vertical feet above the valley floor. Thanks for the help and options. ill be looking into the radio options.

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sommersoft
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Location: Delaware, US

Re: Long Range Transmitters/Recievers

Wed Jul 15, 2015 9:51 pm

Second time in two days I get to recommend this. I'm really just living vicariously through you guys....I'll get around to playing with it eventually myself. :D

XBee!

https://www.sparkfun.com/pages/xbee_guide

EDIT:
Decided to dig a little deeper. There are plenty that will go 1/2 a mile LOS (or 40 miles...in case you want to run a machine on a different mountain..range). The 900MHz models seem to be the ones you'll want, although they are more expensive and you'll need two. An added bonus: Operating Temps are -40 - 85 degrees C (humidity ratings aren't readily available; wrap it in dessicant). They even have gateways, so you can network them even further. It seems one of their target markets is Wind Power. Seems a pretty good match to your needs.

This guy has a pretty good RPi + XBee writeup.
http://www.brettdangerfield.com/post/ra ... r_project/
"We mock what we don't understand." - Dr. Trowbridge

Skipoint0
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Joined: Mon Jan 12, 2015 9:33 pm

Re: Long Range Transmitters/Recievers

Thu Jul 16, 2015 1:10 am

sommersoft wrote:Second time in two days I get to recommend this. I'm really just living vicariously through you guys....I'll get around to playing with it eventually myself. :D

XBee!

https://www.sparkfun.com/pages/xbee_guide

EDIT:
Decided to dig a little deeper. There are plenty that will go 1/2 a mile LOS (or 40 miles...in case you want to run a machine on a different mountain..range). The 900MHz models seem to be the ones you'll want, although they are more expensive and you'll need two. An added bonus: Operating Temps are -40 - 85 degrees C (humidity ratings aren't readily available; wrap it in dessicant). They even have gateways, so you can network them even further. It seems one of their target markets is Wind Power. Seems a pretty good match to your needs.

This guy has a pretty good RPi + XBee writeup.
http://www.brettdangerfield.com/post/ra ... r_project/
jeez, you got knowledge on these things. Ill definitely check it out. its important that they have long range, because they may be MILES apart. the largest resorts have a distance of 6 miles between their base and outermost guns. -40 is a magic number too, because at -38 it actually becomes too cold and dry for snow to fall, or be made for that matter. Thanks for the help!

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sommersoft
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Location: Delaware, US

Re: Long Range Transmitters/Recievers

Thu Jul 16, 2015 4:04 am

Skipoint0 wrote:jeez, you got knowledge on these things. Ill definitely check it out. its important that they have long range, because they may be MILES apart. the largest resorts have a distance of 6 miles between their base and outermost guns. -40 is a magic number too, because at -38 it actually becomes too cold and dry for snow to fall, or be made for that matter. Thanks for the help!
Nah, not really. I just read datasheets quick. :D I also have a touch of ADD when it comes to projects, so I start running around getting lost in reading what/how I can add things. It generally results in little getting finished.

But, your possible project has me intrigued. Most of the contact I have with XBee involves UAVs and 20 mile flights, so this is refreshing. I'll definitely subscribe if you plan on moving forward and keeping us up to date. :hint::hint:
"We mock what we don't understand." - Dr. Trowbridge

mikerr
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Contact: Website

Re: Long Range Transmitters/Recievers

Thu Jul 16, 2015 6:58 am

Also look at Unifi stuff:
https://www.ubnt.com/products/#broadband/wireless

I've had 5Mbps at 10km with nanostation M5s,
very easy to setup.

How often does the "mobile" station move?
Android app - Raspi Card Imager - download and image SD cards - No PC required !

Skipoint0
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Joined: Mon Jan 12, 2015 9:33 pm

Re: Long Range Transmitters/Recievers

Thu Jul 16, 2015 10:33 am

mikerr wrote:Also look at Unifi stuff:
https://www.ubnt.com/products/#broadband/wireless

I've had 5Mbps at 10km with nanostation M5s,
very easy to setup.

How often does the "mobile" station move?
Up and down trails every 1-48 hours. check out image searches of downhill ski maps to see what the area for larger resorts can be like. i have a snowmaking system now, but water and air control are totally manual, so long distances means long travel, even for a seemingly unnoticeable temp change. better snow because of accuracy is what im looking for.

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sommersoft
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Location: Delaware, US

Re: Long Range Transmitters/Recievers

Thu Jul 16, 2015 2:04 pm

Those definitely have some serious range offerings at impressive speeds. But, I didn't see any with <24v or non-PoE power options. I'm on my phone, so data sheet cruising is tedious.

@mikerr
Are these targeted more towards full desktop PC usage, rather than micro/embedded? Probably totally viable if Skipoint0's base station has workstations available. What's the cost like?
"We mock what we don't understand." - Dr. Trowbridge

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sommersoft
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Location: Delaware, US

Re: Long Range Transmitters/Recievers

Fri Jul 17, 2015 11:00 pm

So, if I didn't say this before, I'm pretty interested in your project. So, on my way home from work I was just kind of envisioning the setup and I though about the operating temperatures at the machines.

While the XBee and the Unifi devices are rated to -40C, I remembered the FAQ on the RPi when I was deciding what to replace my Parallax Propeller with.
8. What is its operating temperature?

The Raspberry Pi is built from commercial chips which are qualified to different temperature ranges; the LAN9512 is specified by the manufacturers being qualified from 0°C to 70°C, while the AP is qualified from -40°C to 85°C. You may well find that the board will work outside those temperatures, but we’re not qualifying the board itself to these extremes
So, the Pi may not work all that well at -38C; one of those critical points I assume you'll want it to (if T < -38 then shutdown).

Enter the lowly enclosure heater! You could also go with a silicone heat blanket. I would stay away from the fan driven ones, mostly b/c of condensation problems (I think you'll be fighting that anyway, if the RPi will be at the machines).

Here is a good source, that I found when I was looking for a project solution at work.
https://www.omega.com/subsection/enclosure-heaters.html
"We mock what we don't understand." - Dr. Trowbridge

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