GPS Antenna Location

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jigfish

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I purchased a Northstar GPS and it calls for the antenna to be located 10 feet from the radio antenna. My radio antenna is located on my hardtop right above the helm on a Seafarer 226. Any suggestions?
 
Locate it on the opposite side of the hardtop and lower, that 10 ft is from the tip of the antenna, the heighest point where it transmits from, so that should get you pretty close to 10 ft away. If you have an 8 ft antenna which is typical, being center line and 1 ft off the hardtop which would more then account for the mount would give you the space required, so being on the opposite side would be more then enough room. My GPS antennas are mounted about 1.5 ft inboard of my antennas and about 1 ft off the hardtop and I have never had an issue with getting a gps signal.
 
This is an interesting subject. On my previous boat with a hardtop we kept on getting gps signal dropout whenever we would transmit on the VHF.
Tried many things but to cut a long story short I read in the manual on the new gps aerial that it needed to be a metre away from any radio aerials. So I moved the new GPS antenna as far away as poss.(approx 1 mtre) .....no more problems at all.
On my Grady the tech decided to try the Furuno GPS chartplotter antenna INSIDE the electronics box............That's where it lives and we have not had a problem in 12 months. I have another aerial for my gp32 on top of the hardtop approx 2 feet away from vhf aerial with no issues so far.
All I can say is it depends........
 
8' from the tip of the antenna should be sufficient.

Here is what the top of my hardtop on my 226 looked like...and I never had any issues with the signal dropping out...

S3500408-copy.jpg
 
Most important thing is to not have the signals at the same height, that is more important then anything else, that will confuse the signals, having one higher then the other is what will change if it works or doesnt work. Mine are located like pathery's.
 
Guys, Thanks so much for your help.

Parthery, many thanks for the picture.

I am using an 8 foot antenna so it looks like I'm in good shape with all your advice.

I think will try it inside the the electronics box to save some drilling and move it if that doesn't pan out.

Have a great year on the water.. I'm on Lake Erie..
 
Putting it in your electronics box might put it too close to your compass, I know that can often be a bigger problem then vhf antennas at times, not sure if your gps antenna specifies that or not. Putting the gps antenna as high as possible will help it get a bitter signal and hold it, the lower you go the more chance of a dropped signal which isn't something you want on the water.
 
If you have radar you need to make sure the gps is above the radar beam. The radar will affect the gps.
 
freddy063 said:
If you have radar you need to make sure the gps is above the radar beam. The radar will affect the gps.
Click to expand...

This is a definite...if the radar beam crosses your GPS antenna, and its not well shielded, it will toast it. My Lowrance antenna got fried by a boat that was tied up to me in a raftup. Good news was Lowrance was aware that it was a problem and sent me a new one that was shielded better. Apparently I wasn't the only one with a problem.
 
If you have radar you need to make sure the gps is above the radar beam. The radar will affect the gps.
Click to expand...

This Weekend's Project:

How about below the radar beam? I have a Northstar Radome and a 5" Seaview mount. The top of the GPS mushroom will sit just below the radome so I thought I'd lower the GPS antenna by 3" right tp the hardtop to be sure it's below the beam.

The reason I'm not going higher? Height restrictions plus it would turn this job into a real PIA I think.
 
Why not take the mushroom apart, and use just the hockey puck?

You can mount it to the hardtop with all-weather double stick tape and "try it out". Once you are sure it works well, then drill your holes.
 
Why not take the mushroom apart, and use just the hockey puck?
Click to expand...

I looked at the manual to do just that but then I'd have holes where the mount was... so I'm using the same style mount, just a lower one.

Question is, will the GPS signal be comprimised going through the radar beam?
 
Why not take the mushroom apart, and use just the hockey puck?

You can mount it to the hardtop with all-weather double stick tape and "try it out". Once you are sure it works well, then drill your holes.
Click to expand...

Oh. I Get it. Temporary :oops:

Yeah, once I get the radar going, see how it looks. I'm not in the water yet so it won't be much of a test though.

Thanks
 
above or below, both are ok. If the radar beam is inline with the gps, the power of the radar is a strong signal that could fry the gps reciver. It's not that the gps will not work right, it's that it might kill it for good.

you can add a http://www.westmarine.com/webapp/wcs/st ... /0/0?N=377 710&Ne=0&Ntt=ANTENNA EXTENSION 12"&Ntk=Primary Search&Ntx=mode matchallpartial&Nao=0&Ns=0&keyword=ANTENNA EXTENSION 12 to any antenna and that should get above the radar here is my boat with the two gps antenna port side top of hard top.

boat272.JPG
 
Radar beams angle at about 20 degrees up and down, so depending on where it is located, that will change how mush higher or lower the gps should be from the radar beam.
 
Imo, you should always use a mount for the radar. The larger the top, (T-top/hard top area) the higher the mount, so the radar's beam clears everything.

I've always mounted satalite receivers, (gps, XM weather, Serius, etc) below the radar's path, either on the shortest stantion type mount, or surface mount, (puck). That way, there's no risk of breaking the radars beam. I prefer the short stantion to surface mount, because I believe it will "see" a satalite that's low, on the horizon, better than a surface mounted one. In either case though, I've never had a problem. Also, I think the further away from the radome or array, the better the "view".
 
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