Thanks again G & Prop Swinger.
Having spent more time on the investigation I have all but concluded an iphone would be too much of a compromise and at a not insignificant cost.
I have an ipad2 at the moment running Skydemon, I do not have a current stead so have no way of knowing whether the ipad will be primary or backup.
As I am in the market to buy a GPS unit it made sense to establish if there was one which had some flexibility. The idea of buying one which could run SD from a micro SD makes sense.
Having spent some time looking at units today I have concluded that although the Etrex range is a nice size to handle the screen is a tad small. The Montana seems to offer greater flexibility and is therefore a candidate?
Does anyone have any experience of this unit, specifically:
a) Does it acquire and hold the GPS signal in the air?
b) Will it run Skydemon from a micro SD OK?
Thanks,
BB