GMRS + ham with 2 possible antenna locations (lesser of 2 evils.)

patchesj

New member
I have a Sprinter Van, a GMRS radio and a VHF/UHF radio. Currently there is an NMO mount on the roof for the GMRS. I want to install my VHF/UHF in the van as well but don't want to drill/run another cable to the roof. So... I can mount either of the radios under the dash and a new second antenna on the hood hinge. My question is... Which one would lose the least performance mounted on the hood? The one advantage of the GMRS on the roof is that I am running one of the short 6" antennas up there and there is minimal increase in vehicle height. At a minimum a VHF/UHF up there would add 15", but on the hood the top of it would likely stay well below the roof line. Thanks!!
 

mep1811

Gentleman Adventurer
Higher is always better. You can run a low profile GMRS antenna on the roof and a longer high gain antenna off the hood.
 

DaveInDenver

Middle Income Semi-Redneck
This is a "sort of" question because whatever is on the roof is going to be better but some antennas benefit more from large planes under them than others.

And in the case of a simple 1/4λ having a sufficient planes under it is basically mandatory, which is probably what you're getting with a ~15" tall VHF antenna or a ~7" UHF/GMRS. With others, like a 1/2λ no-ground plane options, then it's a question of coverage more than fundamental tuning.

But the key question IMO is what you expect as far as performance. If you want to talk a mile or two simplex between vehicles then it almost doesn't matter which is where.

OTOH if your expectation is being able to hit stations 35 miles away with a 5 watt handheld then your choices matter much more.

If I was a guessing person I'd say many people are only concerned (at least in the abstract) with GMRS in a local simplex way while ham radio expectations are to reach repeaters, which would imply the dual band ham antenna on top, the GMRS lower.

This would be particularly true if the other GMRS stations are using handhelds or might be FRS radios. Even a poor external antenna is going to be head-and-shoulders better than one on top of a handheld so you're doing the heavy lifting on that comm path.

Thus if as far as a suggestions I'd personally put the ham dual band on top and a modest gain (perhaps will also be about 15" tall) GMRS antenna on the hood. That way you get some gain and less touchy tuning on GMRS and decent performance without a lot of height on 2m/70cm.
 

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