Want to make robust wifi voip site

Looking to build a wifi voip portable unit to be put on the road. I have been in emergency hamradio communications for a number of years but want to build this for commercial reason. I have asked in #asterisk about the quality of some of the voip phones avaible but most users say thay suck. If there is one that is robust, have long battery life and have features like PTT that Push to talk like that on the Mic or Nexus phones then please contact me.



I looked for the same thing but the handheld units got bad reviews.
Using a WiFi station adapter with an external antenna has given me a range of almost 5 miles in the country. Alot of the problems of low working range comes from interfearance from RADAR / microwaves and other WiFi devices. There is alot of usefull information on War driving sites about long range antennas and devices. Since VOIP over wireless is realy just WiFi stuff any info on wireless is usefull.