GPS Antenna

Andy Jones · Post by **Andy Jones** » Mon Mar 12, 2012 1:24 pm

would it be a bad idea to leave a Lowrance Gps antenna exposed in the elements 365 day's a year! i was thinking about mounting mine on the roof or in the windshirld wiper valance area. just dont really know how well they hold up to the elements.

ChaseTruck754 · Post by **ChaseTruck754** » Mon Mar 12, 2012 1:42 pm

you should be fine. Keep in mind these things are used as chart-plotters on boats all the time & the antennas are often permanently mounted to the boat, which often live in a harbor somewhere.

That being said - I'm thinking I'll mount mine on the dash like Tony did (just be sure to keep it 18" or so clear of the head unit or it can mess with the antenna) so it's harder for a thief to grab.

Silverslk · Post by **Silverslk** » Mon Mar 12, 2012 2:47 pm

ChaseTruck754 wrote:you should be fine. Keep in mind these things are used as chart-plotters on boats all the time & the antennas are often permanently mounted to the boat, which often live in a harbor somewhere.

That being said - I'm thinking I'll mount mine on the dash like Tony did (just be sure to keep it 18" or so clear of the head unit or it can mess with the antenna) so it's harder for a thief to grab.

I mounted mine on dash too. I am going to relocate to roof. I get alot more "lost signal" than I would like. Hope that fixes it.

ChaseTruck754 · Post by **ChaseTruck754** » Mon Mar 12, 2012 2:51 pm

I can't remember - is yours on the same spot in the dash as Tony's? I don't remember him having much issue with loosing signal...

Silverslk · Post by **Silverslk** » Mon Mar 12, 2012 2:59 pm

ChaseTruck754 wrote:I can't remember - is yours on the same spot in the dash as Tony's? I don't remember him having much issue with loosing signal...

Pretty close to it within an inch or something I would guess. It "might" be the older 3000 that I borrowed from you vs a newer 4000?

ChaseTruck754 · Post by **ChaseTruck754** » Mon Mar 12, 2012 3:20 pm

I'm pretty sure Tony's antenna is a 2000, & even if that isn't the case that shouldn't be the issue.

Silverslk · Post by **Silverslk** » Mon Mar 12, 2012 4:14 pm

ChaseTruck754 wrote:I'm pretty sure Tony's antenna is a 2000, & even if that isn't the case that shouldn't be the issue.

His is the "Baja" something.....supposed to be same as 4000. Either way, I need to buy one soon and get you yours back. I'll try out the 4000 and if it still drops alot....on the roof it goes.

ChaseTruck754 · Post by **ChaseTruck754** » Mon Mar 12, 2012 4:29 pm

Baja is the same as whatever was current at the time (so Tony's should be a lgc-2000), just with "anti vibration whatnots" done to it (= it's been siliconed). No difference in antenna itself.

If you want I'll let you try my other antenna on it. It's a "baja" since it's off the Baja 540c. Same thing - just priced more...

PaulW · Post by **PaulW** » Mon Mar 12, 2012 5:09 pm

GPS uses regular radio signals which means they work just fine looking thru glass or fiberglass. The disadvantage of the dash mount is the ant is shielded from sats aft of the truck - not optimum. Mine is crammed between the cage and the shell. Same signal strength as on top of the roof.
I use my hand held with a long RAM mount sucked to the windshield in my pickup and it works just fine. So much for shielding by the roof.

Same result for the 2000, 3000 & 4000 ant.

BTW the same comment applies to the sat radio ant.

No need to mount on the roof.
PaulW

Silverslk · Post by **Silverslk** » Sun Apr 22, 2012 6:15 pm

So, I bought my GPS and it came without an antenna. I scored one on RDC tthis weekend and have been questioning the location I chose for the antenna. I took the antenna and extension cable it came with and went out and played around to see what difference (if any) I could see from locations. Here are results from sitting in the street in front of my house in Garden Grove. Your results may vary but interesting nonetheless.

Note: The reason I don't like my choice is a few times (on road) I have experienced "signal lost". Mind you, this was in a canyon going to Havasu Springs Hotel from Parker but still annoying. But got me thinking about being in a canyon in the desert and possibly losing signal as well.

Silverslk · Post by **Silverslk** » Sun Apr 22, 2012 6:17 pm

A few more spots.

tcm glx · Post by **tcm glx** » Sun Apr 22, 2012 7:05 pm

Andy,
What are the different readings your displaying in those pics?

I have not had any "signal lost" issue with it on my dashboard, not saying its optimum, just stating I haven't had issues.

Silverslk · Post by **Silverslk** » Sun Apr 22, 2012 7:53 pm

Its the number of different satellites and the strength. If you hit the PAGE button and then select over to satellites (or something like that) you will see that screen.

What I found interesting is that (in my street) the dash had better and more reception than the cowl. I'd love to see some other post up similar.

I only had the signal lost issues in a downtown environment and on that curvy road to Havasu with large hills on 3 sides (forward, left and right) and I wonder if the roof was obstructing and signal from the rear. you know what I mean?

tcm glx · Post by **tcm glx** » Sun Apr 22, 2012 8:01 pm

Got it.....I'll post some in a week or two

BajaF250 · Post by **BajaF250** » Mon Apr 23, 2012 7:38 am

Hey Andy,
That's a great experiment! It looks like you clearly have better signal strength and more satellites when the antenna is mounted on the roof. But again, you only need 4 satellites at any one time to keep your positioning so that may not be a factor. The same theory goes with mounting it on the dash, since the roof shadows any satellites that are behind the vehicle (whatever relative position that may be) when you still have 4 satellites in view, you will have good positioning data.

One thing to consider when mounting the anteanna to the dash is when the vehicle is constantly changing directions, different satellites will be "exposed" and "shadowed" by the roof which will force the GPS to have to switch satellites constantly. I'm sure the GPS has no problems with that, but in a low signal strength environment or low satellite exposure environment, you will most likely experience GPS positioning degredation.

BajaF250 · Post by **BajaF250** » Mon Apr 23, 2012 7:42 am

I'm running the LGC-3000 "Baja" (whatever that means). I have mine mounted on the roof, 365. Like Steve mentioned, they are deisgned for constant exposure in the marine enviroment. I have had no issues with my antenna with either environment degradation or reception. I did "ruggedize" it for off road use... I drilled 2 small holes in the upper side corners and completely filled the interior of the shell with silicone. Apparently, the antennas will have a shorter life due to excessive vibration and "shake apart" internally. They then stop working. So, the old racers trick is to full them with silicone... I've been running mine now for many, many years and it's still working great!

Silverslk · Post by **Silverslk** » Mon Apr 23, 2012 7:54 am

BajaF250 wrote: The same theory goes with mounting it on the dash, since the roof shadows any satellites that are behind the vehicle (whatever relative position that may be) when you still have 4 satellites in view, you will have good positioning data.

One thing to consider when mounting the anteanna to the dash is when the vehicle is constantly changing directions, different satellites will be "exposed" and "shadowed" by the roof which will force the GPS to have to switch satellites constantly. I'm sure the GPS has no problems with that, but in a low signal strength environment or low satellite exposure environment, you will most likely experience GPS positioning degredation.

These were my thoughts/concerns as well. I figured, the more I have access to.....the less chance I lose reception. If I only have 5 or 6 and I get in a low reception area I could lose one or two of the only ones I have. Make sense?

BajaF250 wrote:I'm running the LGC-3000 "Baja" (whatever that means). I have mine mounted on the roof, 365. Like Steve mentioned, they are deisgned for constant exposure in the marine enviroment. I have had no issues with my antenna with either environment degradation or reception. I did "ruggedize" it for off road use... I drilled 2 small holes in the upper side corners and completely filled the interior of the shell with silicone. Apparently, the antennas will have a shorter life due to excessive vibration and "shake apart" internally. They then stop working. So, the old racers trick is to full them with silicone... I've been running mine now for many, many years and it's still working great!

I've heard the "Baja" antennas have the silicone in them to help with vibration already. Any pics of yours? I would consider doing mine the same way.

When mounting on your roof, did you drill 2 or 4 holes and mount it directly? Ever have a leak?

BajaF250 · Post by **BajaF250** » Mon Apr 23, 2012 8:09 am

Hey Andy,

When I drilled into my antenna casing, I saw no silicone... now that doesn't mean they didn't put a light coating on circuit board, something I couldn't see through a tiny 7/32" hole... but the circuit board looked clean from my point of view (again, through the tiny holes), so I just took the tube of fresh silicone and squeezed it in until it came out the other holes... pretty simple.

I was a little paranoid of my antenna failing so I went looking for a spare... when I bought my GPS, it came with the antenna so I was absolutely shocked that they were SO expensive... wow... but I found a marine store right around the corner that was selling used one... $20 each... I bought two!

I don't have any pics... but I should be able to snap a few this afternoon for you...

I used only two screws when mounting... never had any issues with leakage.

BajaF250 · Post by **BajaF250** » Mon Apr 23, 2012 8:16 am

Andy,
When you analyzed the different antenna positions on the truck and compared it to satellite reception, did you do all of that at about the same time of day? The reason I'm asking is that the GPS constellation is made up of 32 different satellites that are not geosynchronous which means when you are in one position, the satellites will change over a period of time. But, from what I can tell from the photos, it looks like the GPS is looking at the same satellites so that tells me that you did your experiment all at about the same time.

Silverslk · Post by **Silverslk** » Mon Apr 23, 2012 8:52 am

BajaF250 wrote:Andy,
When you analyzed the different antenna positions on the truck and compared it to satellite reception, did you do all of that at about the same time of day? The reason I'm asking is that the GPS constellation is made up of 32 different satellites that are not geosynchronous which means when you are in one position, the satellites will change over a period of time. But, from what I can tell from the photos, it looks like the GPS is looking at the same satellites so that tells me that you did your experiment all at about the same time.

Yes, all the pictures were taken between 5:03:33pm and 5:10:34pm (I have higher res pictures and looked at clock displayed on screen).

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