RE: DX18 Yes or No need advise please!
The power output of the Spektrum Tx's is software controlled. That's all to do with different countries allowing differing max power outputs. The USA allows the highest power output, UK next lower, and France rather lower than UK. Plus there may be other variations, but all lower than the USA's allowance.
The upshot of this is that when it was first released, the power output of the European Tx's on V1 software was lower than actually allowed. I did have a range problem with my V1 software but flew the plane, a slope soarer, close-in as I only range-tested on the day of the first flight and didn't want to drive all the way home through muddy country lanes (needing an hour's car washing) without flying my nice new Tomcat mouldie. In years gone by I've flown a lot of home-brew R/C equipment which I'm convinced wouldn't be anywhere near as good as today's commercial stuff so decided to trust the DX18, and was lucky that day whilst reading on RCG that others had not been so lucky. The European low-power issue was soon notified on the RCGroups forum by someone who had the technology to do the measurements. Very soon afterwards the proper power output was programmed in, and if you have the latest software you should be OK. On V1 software my range check didn't even achieve the required 30 paces, or whatever it should have been. Now, there's no problem and I've had very many (small) jet, (large) gas and (fast) glider flights with no issues.
YMMV
Gordon