ORIGINAL: alfredbmor
While crystals are different in single and dual convertion receivers, it does not neccesarily mean that the range of a single convertion receiver is lower than a dual convertion receiver, but I guess that in fact it depends on the price that you pay for a particular receiver.
Please read this:
http://www.bergent.net/SC-DC.pdf
You are absolutely right that "conversion' has nothing to do with range.
The tech notes for the GP Elictrifly receivers specifically say, "Approximately 890 feet of maximum range."