I purchased the Sony ICF-7600GR and should get it in a few weeks.

I was also looking at scanners that can "hear" above 30MHz. This
particular one goes up to 3GHz. It's the portable AOR AR-8200 MKIII B.

My question is, since I am new to all this, what frequencies does the
default antenna that comes with the unit allow me to get? And do I need
to buy other antennas to get other frequencies? How many antennas will
I need to get all frequencies? Is this a huge cost?

Since it's a portable unit, I am assuming I don't need one of those
huge antennas that you see at some peoples houses sticking out of their
backyard 300ft high (obviously no HOA [home owners association] there.)

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Thanks in advance,
clu