Ask around for the local ham radio club... Hams who operate in the 80
meter and 40 meter bands will be familiar with propagation issues and
how to determine if you have a cable or antenna problem, and with
setting up the radio on the proper sideband, proper bandwidth, tuning,
etc...
Hams are a great resource for boaters with HF radio issues... Just be
aware that hams have various license classes and the fellas with a
technician level license will not have HF experience, for the most
part... But, any ham with a license rating higher than technician
likely speaks HF radio fluently...

denny - k8do