Wireless I/O without Line of Sight - Options and Suggestions?

I been chasing my tail on this little project and hope someone with past field experience can offer some suggestions.

I'm trying to get an analog signal about 2000 to its destination.

Location: Outdoor but I have power at both location. The problem is with the path, it's about 2000 ft as crow flies, now, that's not bad but...imaging a long very narrow river canyon that take a 90 degree bend. The receiver is on top of the canyon and the transmitter is on the down around the bend at the river's edge. Well, that's a problem.

I talked with a few wireless vendors, the usual suspect, B&B, Phoenix Contact, etc... none can promise that it will work. One basically told me that RF signal don't get along with earth obsruction.

However, using B&B's ranger estimator at http://www.bb-elec.com/WirelessRangeEstimator/, putting the best yagi on a 900mhz system does get me a range of about 3000 ft for "indoor" and 4500ft for "outdoor urban". So... I am cautionly optimatic that it will work but I do want to be sure before I start buying stuff.

So, what do the experience of folks with this type of install?Does anyone know of RF testing equipment I can rent to estimate the dB loss between two locations?

Could you setup a repeater between the 2 points. They have systems that use dc power and have a solar panel to keep the cells charged. Is that a possible option?

I know a guy in our area who does consulting on exactly this sort of thing, Harry. He'll have access to radios, antennas, and test equipment (and expertise) so you can be sure of the signal and data conditions before you install the hardware. He and I talked about a project just this afternoon.

Drop me a PM if you're interested.

Not really an answer but good advice (maybe you've seen it already):

The 10 commandments of wireless

The earth between the high end and the low end kills the signal from license free frequencies that are used, unless there's some steel that the signal can bounce off of.

So my experience at a couple dozen sites using 900MHz says that you probably will not have have enough RSSI fade margin to work reliably, if at all.

If there's some steel superstructure near the bend of the river, or at top of the canyon near the transmitter, you could get "bounce" that will give enough RSSI at the receiver end. 1 watt 900MHz wireless works really well in refineries where you rarely 'see' the other end.

2.4GHz DSSS (direct sequencing) sucks for this kind of application. Avoid at all costs. It'll never work.

I remember seeing large white billboards on mountain ridges in the western states, with nothing printed on them. I was told that they were used to bounce the television and radio signals down into the valleys. Not sure if anyone sells these things.

Shawn

Have you investigated the microwave links - I understand (because these are highly directional) they can easily be bounced off a relatively small reflector plate.

i'm no expert at all, and wouldn't know where to look, but these things are used everywhere for data-comms between buildings, and at substantial distances

A mesh network would work if you could put a few more nodes in.

Hello Harryting,
From the information you have given, you’re coming across a common problem for people who are looking for a wireless solution to their applications. It sounds like you’ve done your homework, but if you are looking for any other resources, you can get in touch with your local Phoenix Contact salesperson and they can come and do an onsite test depending on terrain conditions. Furthermore Phoenix Contact also offers a Path Study service free of charge. If you are able to provide GPS coordinates of locations you would like to deploy a wireless system, we can run a site analysis and provide guidance on how you would need to implement a wireless system to make it work reliably. This would include both antenna and antenna height recommendations and if you would need a repeater, a suggested location of the repeater. If you would like more information about the Path Study service, please contact our Technical Service Department at 1-800-322-3225. Now for the problem at hand, as was mentioned if you have a location for a repeater, this would be an easy solution to the problem and should work with the distances you have described. We hope this information is useful.

Old post alert

PhoenixContact said:

Hello Harryting,
From the information you have given, you’re coming across a common problem for people who are looking for a wireless solution to their applications. It sounds like you’ve done your homework, but if you are looking for any other resources, you can get in touch with your local Phoenix Contact salesperson and they can come and do an onsite test depending on terrain conditions. Furthermore Phoenix Contact also offers a Path Study service free of charge. If you are able to provide GPS coordinates of locations you would like to deploy a wireless system, we can run a site analysis and provide guidance on how you would need to implement a wireless system to make it work reliably. This would include both antenna and antenna height recommendations and if you would need a repeater, a suggested location of the repeater. If you would like more information about the Path Study service, please contact our Technical Service Department at 1-800-322-3225. Now for the problem at hand, as was mentioned if you have a location for a repeater, this would be an easy solution to the problem and should work with the distances you have described. We hope this information is useful.

Click to expand...

I hope this is not a thinly disguised advertisement, Phil plainly says at the top of the page, " This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc."

Probably a simple reference to a company or link would be more appropriate.