Hi, i recently purchased a handheld vhf as a backup second hand off trademe (same as this http://www.marine-deals.co.nz/cobra-mr-hh125-handheld-vhf-radio)

upon testing it with the one mounted in the boat it only seems to work on some channels, not including the local one 64. Both radios will work perfectly fine on channel 9, both are set to international. But my new hand held will not transmit on 64. If i set both radios to canada they will talk to each other.

Have I brought a dud or am I doing something wrong?

Thanks.

My understanding (and I might be wrong) Base channels transmit on one frequency and receive on another so to transmit you must have the power to trigger the repeater back on land. Make sure you are transmitting on maximum power setting for the handheld. 

You mention both set to international so should work - when u say not transmitting on 64 - you mean boat radio not picking up handheld?  Have you tried a couple of blocks away from other radio just in case something to do with gain and adjusting squelch on receiver?

Took the vhf out in the boat today just incase and what do you know the mounted unit failed half way through the day and the new handheld worked like a charm, so buggered if I know how but I'm pleased it worked when needed.