We started out with a nice Soney portable short wave receiver only, and with a
modem connected to the
laptop, it was able to download
Weather Fax as well.
You may get better
reception by connecting the wire to a chainplate or
mast bolt. Since it can't transmit, it can do no harm. It also "might" be better (IF it's a portable with LONG telescoping antennae), to receive in the
cockpit, & swivel it for best reception.
Experiment...
22 years ago, I have used an "either / or" switch to share the
VHF with a FM
radio, and it had some form of protection for the VHF, should the mike get keyed with the switch in the wrong position.
WARNING... You will blow out the VHF to key the mike with no antennae attached!
Also... a simple splitter will not
work. When using the VHF, it would send it's
transmission into the antennae AND the short wave
radio, which is bad for both.
I would therefore avoid the VHF option as too risky.
Experiment with the rig option, it can't hurt...
Mark