best pic to pic wireless link?

[ghostman11]

i am looking for a pic to pic wireless solution, my main problem is distance i want it to send from a polytunnel type structure 250' to a fairly thick stone walled building. i could in therory have a reciever set up outside the stone building and relay from there via cable to another pic to display the data.
the sending pic will be doing all the work and the data it will be sending is purely for monitoring. i cant go for a all wired solution due to the location of the structure. has anyone got any sugestions or links to equipment that might do the job?

 

[ronsimpson]

I am playing with xbee-pro. The price is high. With a whip antenna I can do line of sight. (mile) The 900mhz works very well. The 2.4ghz will not work in the rain! (our doors) not in fog and will not work miles when there is water in the air.

The little $10 radios I can only get 20 feet out of.

With a really good home made antenna I have a solid connection, 5 miles, at 2.4ghz when it is not raining. (directional antenna) I recently changed to 4.8ghz and now it works in the rain.

 

[ghostman11]

we get alot of rain here! so would you recomend the 4.8ghz then? as far as price goes i dont have much option i need a solution that will intergrate with the equipment and controllers i have already (pic based) and will work. so cost wis i am just going to have to swallow hard be brave and spend the hard earned

 

[ronsimpson]

Water resonates at 2.4ghz. That is how a microwave works. Stay away from 2.4ghz because you get rain.

 

[ghostman11]

Water resonates at 2.4ghz. That is how a microwave works. Stay away from 2.4ghz because you get rain.

i wouldnt want it sat on my lap then cheers for the info, and yes we get a huge amount of rain and mist and fog and just about anything else thats damp/wet
once i get the units i will get you to run through making the attena better, distance isnt so much my problem but the building (my farm office) is very thick stone walls (2 1/2 feet thick) i have real trouble getting a wireless internet signal in there.

 

[jpanhalt]

The effects of rain and fog are worse at the higher frequency. See last paragraph: **broken link removed**

@ronsimpson: Can you provide a link for, "Water resonates at 2.4ghz. That is how a microwave works."

John

 

[Ian Rogers]

Ghostman!!! I use these...**broken link removed**

They operate at 900mhz, they can do about a mile, they plug into an xbee socket, they are networkable....aaand they are only £9.90 each...

 

[ghostman11]

Ghostman!!! I use these...**broken link removed**

They operate at 900mhz, they can do about a mile, they plug into an xbee socket, they are networkable....aaand they are only £9.90 each...

that looks like it will do the job! i know this sounds stupid but i take it i need 2 of them? one for sending and one for recieving?

 

[Ian Rogers]

Yep! They don't usually need configuring... unless you need to.

 

[ronsimpson]

Also at http://www.robomaa.com/index.php?ma...Path=1002_117_119&products_id=975&language=en
Xbee makes 900 mhz also.

 

[Ian Rogers]

Xbee makes 900 mhz also.

I've tried these as well... but the cheapest are about £22 (twice the price) the current consumption is also too high for battery operation..

VERY good distance though.

 

[ghostman11]

yeah i will try the cheaper option first if that dosnt have the punch then i will have a try of the others as long as it works i will be happy funny thing is i have always thought the wireless thing was a bit of a waste of time lol

 

[leftfield95]

You need to stay clear of the 900MHz band in the UK and lots of other countries, its mainly used for GSM (Vodafone & O2).
900MHz for ISM use, is generally only allowed in North & South America and Australia, some other countries may have adopted it also, if they don't use the GSM900 band.

For use in the UK you can use 433 and 868, although 868 was originally designated for use with RFID and alarm systems, it permits a 10% duty cycle so sending small packets of data from sensors should be OK.

Regards,
Leftfield95

 

[ghostman11]

You need to stay clear of the 900MHz band in the UK and lots of other countries, its mainly used for GSM (Vodafone & O2).
900MHz for ISM use, is generally only allowed in North & South America and Australia, some other countries may have adopted it also, if they don't use the GSM900 band.

For use in the UK you can use 433 and 868, although 868 was originally designated for use with RFID and alarm systems, it permits a 10% duty cycle so sending small packets of data from sensors should be OK.

Regards,
Leftfield95

i should be able to get away with it as there isnt any kind of mobile signal around here for about 4 miles as for it being illegal well thats only true if you get caught

 

[Ian Rogers]

Based on the Texas Instruments CC1110 combined micro & RF transciever, runs at 868.3Mhz, same chip can support 315, 433, 900 & 915Mhz

This is from the XRF manual.....When I said 900.... Europe is in the 868.3 band so you are ok anyway..

 

[ghostman11]

This is from the XRF manual.....When I said 900.... Europe is in the 868.3 band so you are ok anyway..

to be honest Ian if your using it that good enough for me i always have the dumb farmer card anyway

 

[ghostman11]

ive had a chance to browse through the datasheet and have a look at the support files, looks like a very impressive bit of kit for the money. i will order 2 on monday and try them out, if they work well then i might get a few of them to replace some of the wire connections from the hatchery to the office thx for the link Ian

 

[Wilksey]

If you want a "bulletproof" module, I have used the Radiometrix FPX3 transceiver, they have a 500mW transmitter, and go for a really long distance (from experience!) . They are used in mobile traffic lights and are really robust!

Wilksey

 

[ghostman11]

They are used in mobile traffic lights and are really robust!

Wilksey

hello mate long time no hear i will have a look at them! and as it happens we have a few traffic lights around here LOL

Ive just seen the price of them at farnel :O:O:O:O i have the cheapies on order so will try them but if i cant get through the office wall with the signal then i will order the others.

 

[Wilksey]

They are a tad expensive, lol, but I have tried others from companies such as RF Solutions and although they are good, the FPX-3 really does do a good job, you could try RF Solutions, they are not over expensive, just didn't do the distance for my application. It's worth trying others first because of the price, but if all else fails, you can keep them as backup! lol. There is a reason why they are that expensive, so they may be overkill for your task.