VHF with built in GPS in the Cabin

[cwoflyboy]

I want to upgrade my VHF radio. I am thinking about a VHF with built in GPS.
This would give me a little redundancy but mainly I don't want to run a line from my GPS (at the helm) to my VHF (in the cabin) for DSC capability.
My concern is; will the GPS function ok without a direct view of the sky without an external antenna? A few years ago I'm sure the answer would have been "no", but with GPS improvements, I'm not sure (think your cell phone's GPS in a building). Your thoughts please.

[steamgoat]

I have a standard horizon gx1700 below, once in a while it 'complains' of no signal when turned on,but works fine after half a minute.

[S0808]

90 percent of the time it will work but without actually installing it first there is no way to know.

[GordMay]

Greetings and welcome aboard the CF, South Tackle.

[rebel heart]

Cell phones in buildings are different; they use assisted-GPS, first getting a rough location from cell towers, and possibly ending right there as that can be fairly accurate in urban areas, but if it needs to acquire GPS satellites it happens much faster because of the initial rough-fix. You can try it for yourself: even outdoors with a direct view of the sky, go into airplane mode (turn off your cellular access), and see how long the GPS takes to load. Even for modern phones it can be a minute or two, and if you close out of the app and come back a few seconds later, it's back to another full minute or two.

Regarding GPS receivers inside a cabin, it's always worked for me. Eventually I put an exterior GPS antenna in place for AIS transmission because I wanted to make sure I had as accurate a position (that I was relaying to other vessels) as possible. But the GPS receiver inside my cabin, located a few inches from the cabin top which then had a dodger above it, was fine.

[travellerw]

I installed a GX1700 in July. So far it has worked through my cabin top %100.

[S0808]

Originally Posted by GordMay

Greetings and welcome aboard the CF, South Tackle.

Thanks, glad to be here. Hopefully I can keep an eye on the electronics forum and help out where needed.

[CharlzO]

I have a GX2200 from Standard Horizon, mounted in the cabin and had no issues. I also, prior to installation, moved it EVERYWHERE in the cabin of a Hurley 22 I had in the yard, under a line of trees, to see if it would pick up. Even unhooking and re-hooking it back up at multiple points, from right under the hatch, to the center of the cabin, to back hidden under the quarter berth. The longest it took, was 45 seconds from hooking to power, to get a solid GPS lock. At that point, decided it wasn't going to be an issue on my other boat either.

[colemj]

From an electrical standpoint, your GPS will most likely have a direct view of the sky when mounted inside your cabin. Fiberglass is essentially transparent to the radio frequency used (think about all those fiberglass antennas). If you have a metal boat, or lots of metal over the mounting spot, then this would be different, of course.

Mark

[ka4wja]

cwolfboy,
Assuming you have a fiberglass boat / deck???
You shouldn't have any (or few) issues....


My primary navigation GPS (Raymarine Raystar 125+) is mounted out in the clear, above the aft rail / above the bimini/solar panels....

But, since 2004, I've also been using a Garmin GPS 76 mounted inside at my Nav Station, as my GPS source for both of my DSC radios!!! Without any issue at all....never a dropped signal, and usually tracking 6 - 8 satellites+...even when in some serious Gales offshore, etc...
(and from 2006-2012, this was also my GPS source for my AIS receiver...)

And, since 2012, I have another GPS antenna connected to my AIS transponder, that is on a self immediately forward of my Nav Station....and it too has worked flawlessly!!

Have a look at these photos...

See the Garmin GPS 76...




See the white "Mushroom" antenna, near the upper left side of this photo, behind the fan and basket, to the left of the fan...





Now, I cannot speak for whatever radio you're considering....but if it has a modern GPS receiver (as it most probably does), it should work well for you...(again, assuming you have a fiberglass boat/deck)


I hope this helps...

Fair winds...

John

[FamilyVan]

I have a GX2200 mounted in my cabin, i have never had a signal problem and I have a THICK deck. Glass-Balsa Core- Glass- about 1/2" of teak deck over that.

You should be good.

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[goat]

You might as well get a receiver with AIS while you're at it.

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[S/V Alchemy]

Originally Posted by steamgoat

I have a standard horizon gx1700 below, once in a while it 'complains' of no signal when turned on,but works fine after half a minute.

I have an SH 2200 in a steel pilothouse with an aluminum roof. It acquires GPS and AIS within 15-20 seconds without an external GPS antenna. AIS, even in Lake Ontario, is a great thing to have, and, of course, it's like having an extra speedo to read your own SOG/COG off the VHF.

[barnakiel]

You can run a very simple test by placing a cold handheld GPS where you envision the radio, then start it. See how long it takes to acquire then check how good the signal is.

Check what GPS the radio has, new units may have a 66 Sirf unit onboard or else something even newer = faster acquisition under the deck, better fix and all the newer handles.

We feed our VHF from a handheld Garmin 72 (old, not H model) and we never ever have any signal problems. Our deck is sandwich (foam) and then there is a dodger above it too - plenty of signal obstacles but apparently very little interference (other than slower start).

So, to sum up, it may work very well for you; still make the test to avoid getting unhappy with your new toy.

Cheers,
b.

[FamilyVan]

Cwoflyboy, I just want to support a trend I'm seeing here. If you're getting a vhf with gps, its not a big jump to move up to the SH GX2200, which has an AIS receiver. Its a nice thing to have in busy shipping areas (I'm on the St Lawrence). I keep a CPA alarm on so ships don't sneak up behind me etc.

I think I payed less than $300 CDN for mine.

Which reminds me, Colemj, several months ago you gave me some advice on increasing the range setting, at the time I couldn't figure it out, but I since have.

Thanks

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