I've got a customer who owns a nursery (Plants not babies). He whants a cordless phone so he can roam the grounds. He is in the center of 45 acres. The cost of putting in a specralink system would force him to sell the farm. Is there any other product out there that could offer anything close to cover an area this large?
Check out Engenius with an external antenna mounted as high up as you can get it.
https://www.engeniustech.com/telecom/industrialcordless.html I have one working on a mulching farm of 40 acres and they have had it since 4/2002. That one is the only experience I've had with the product though.
mark
The enginuis should work for you. You can add a 30 or 60 foot antenna extender that will pretty much cover 3-4 mile range.
I've done a few of these. One note though the SN920 not so much but the 436/490 we've had a terrible track record with.
When they work they're great, but I've had a string where I replaced 4 in less than 8 months.
Corwyn
The Engenius cordless sets have a nice long range---really a nice phone---but be sure to get the hardcase to protect the phone---and get an extra battery. When you drop a 3-400 dollar phone it breaks just as easy as a $30 Radio Shack phone.