radio control

[ptonsparky]

I need to have simple on/off control between 2 points about 2700' apart. Line of sight. No wires exist between the points and one is powered by a small genset the other from utility. Is radio viable vs trenching or plowing in a control cable? If so would someone care to suggest a source?

 

[Bob NH]

I just installed some radio controlled remotes for lights at a corral on a small ranch. I bought receivers for $10 each, and transmitters for $7. I was using only 500 meter transmitters, but they are available for up to 3000 meters.

The transmitters and receivers came in a box with big stamps bearing pictures of Mao Tse Tung and Chou En Lai or some other communist mucky-muck. No problems with customs. I was able to communicate with the seller by Email since the auctions didn't exactly match my needs.

http://cgi.ebay.com/12-to-1-Special...090544824QQcategoryZ85899QQrdZ1QQcmdZViewItem

I used 1-channel latching relay receivers, got a 12 Volt power supply such as used on some powered speaker systems, and added a relay to boost the current capacity. I soldered it all together, wired it all into the light circuit, and covered it with a waterproof hood. It's in Texas so it won't see a lot of humidity and the quiescent power of the power supply will keep it dry.

This was done as a favor for a brother-in-law; not something I had to warrant for a year. It worked fine.

 

[ptonsparky]

These are for pivot/well irrigation control. High humidity for 5 months, dry and dirty for 7 months.

thanks

 

[Bob NH]

These are for pivot/well irrigation control. High humidity for 5 months, dry and dirty for 7 months.

thanks

That just means you have to spray on some conformal coating and seal them up. It doesn't affect the electronics. The whole package is quite small. The biggest part was the power supply, which is like a 1/4 size laptop power supply. The receivers are about 1.4" x 1.2" x .8".

 

[ptonsparky]

I looked at them but my use is more automated. No one will be there to push the button. If limit A trips, well B must shut down.

Brings up another project though...are these latching or momentary relays?

 

[Bob NH]

I looked at them but my use is more automated. No one will be there to push the button. If limit A trips, well B must shut down.

Brings up another project though...are these latching or momentary relays?

You can get either latching or momentary receiver relays.

The transmitter works on a switch closure. I'm sure it would be possible to wire it up to operate on a contact closure.

There is probably someone who will sell you a professionally done system for $1000 to $3000 per channel. Or you can do it for less than $100 worth of parts and some time to get the logic organized. Since I'm retired and like to work on that sort of thing, I take the latter route.