Any chance you are hearing images?
Swen - I'll just throw this out there ...
Any chance you are not dealing with the perfect storm of poor image rejection, nearby location, and legal amateur power?
Ie, if your gear has a 10.7mhz IF, and by doubling that to 21.4, if you subtract that from your gmrs freq (depends on whether the rx section does up or downconvert on the IF), that could easily allow you to hear the image of amateurs below you.
Ex: 462.7125 on display. Image heard: 462.7125 - 21.4 (double the IF) = 441.3125 mhz or thereabouts.
Depending on local band allocations, there *could* be an amateur link you are hearing on the image in your own receiver.
This *might* explain why amateurs are actually using their own ID's, because the fundamental IS in the amateur 70cm band.
.. just scratching my head on this one ... and as an amateur trying to resolve the problem from afar...
Swen - I'll just throw this out there ...
Any chance you are not dealing with the perfect storm of poor image rejection, nearby location, and legal amateur power?
Ie, if your gear has a 10.7mhz IF, and by doubling that to 21.4, if you subtract that from your gmrs freq (depends on whether the rx section does up or downconvert on the IF), that could easily allow you to hear the image of amateurs below you.
Ex: 462.7125 on display. Image heard: 462.7125 - 21.4 (double the IF) = 441.3125 mhz or thereabouts.
Depending on local band allocations, there *could* be an amateur link you are hearing on the image in your own receiver.
This *might* explain why amateurs are actually using their own ID's, because the fundamental IS in the amateur 70cm band.
.. just scratching my head on this one ... and as an amateur trying to resolve the problem from afar...