ORIGINAL: RichLockyer
The Polk system scares me... It can only scan what is currently turned on. Does the pilot have full control over it and can he lock it in?
As a Tracker II owner, I can assure you the pilot has full control over what frequency is used. It scans to see if your chosen frequency is in use, and if it's clear, then powers up the RC circuit. If it is already in use, it sounds an alarm, and WILL NOT apply power to the RF circuit.
ORIGINAL: RichLockyer
As for the synth modules, the RX can be changed with a simple crystal swap. I keep reading about low and high band RX, but the only one that can be specified by low/high is Futaba/Great Planes.
That's correct. Futaba is the only company still making high & low versions of their receivers. JR stopped about 8 years ago. There are a FEW other synth receivers out there, but they are far more expensive, and must be removed from the plane in order to change channels, because they use a dial (which can wear out) instead of the auto-sensing method the Seeker uses. Also, I think the Seeker is the only synth Rx which also can do BOTH +ve and -ve shift.