Wireless comms with Linx LR modules

[telemark]

Hello,

I have started a project using PBP, a 12f675 and the Linx rxlc-434-lr modules and need a bit of advice. These receivers appear to offer very good medium range performance, rated at about 1km at 10,000 bps. Unfortunately we have observed lots of noise on the data output pin. This issue is referred to in the manual. Is the only way to eliminate it to use an encoder chip, and if so, why? I am familiar with Manchester encoding but have found in the past that it does not greatly improve data reception with cheaper "Wenshing" modules. We do not really want to use Manchester encoding because at baud rates below 1200 it increases transmission time and reduces battery life.

Also We have found that the RSSI output pin on the Linx receivers offers a much better noise free signal. Has anyone any experience with using this pin for data input to a PIC? We can cope with a baud rate of 600 and are considering amplifying the RSSI output to improve sensitivity. If we cannot get reliable reception at a range of at least 1km it would seem these modules do not offer much advantage over cheaper type receivers. Any thoughts?

Thanks
Mark

[mister_e]

Have you tested it by sending the module output to a comparator ? i have the feeling that it could be handy to reduce noise. If so, and if the hardware permit, you can just use the internal one of the PIC, feed the output to another pin and read directly from it.

Just an opinion. But the manchester stuff is still a good option.

Software noise cancellation is doable so far but need some time to get it reliable and rock solid.