VHF w/GPS install/Is Fiberglass transparent to GPS signal?

[justason]

I recently purchased a Standard Horizon GX1700 for no real practical current need requirement.....

This unit has a GPS receiving node on the face of it. I'm favoring installing this under the dash, in the area under the stereo (right side, near right knee approx). By the time it is not a threat to be bumped or knocked by the pilot it is a decent distance under the dash. and near horizontal.

I'm reading that Fiberglass is invisible or transparent to a GPS unit/signal. If that is true the next block above the unit would be the stereo itself, few switches and wires....then open sky.

Has anyone installed a GPS based VHF and found this to be true ? Is your signal holding strong? There is the option for purchasing/installing a separate GPS antenna, damn thing cost as much as the Radio !!

 

[sstegh]

Don't know about your radio but I installed the GPS receiver for perfect pass under the dash. I only have 1 layer of fiberglass between it and open sky and it works perfectly. You describe having wires and switches in the way too, I wonder if the current in those wires would be a problem.

 

[Glassman]

That's a neat unit, but you might want to consider mounting away from the stereo if possible. That would be the only concern I would have as far as electrical interference goes. It also calls for passengers to be at least 3' from the antenna to limit RF exposure.
Go ahead wire it up temporarily and try it close to the spot where you want it and see how it operates before you actually mount it. Check to see that the built - in GPS antenna will pick up satellites.
If you have a built in compass, check to make sure it doesn't interfere with its operation.
The worst thing that can happen is that you'll need a GPS antenna to pick up satellites. They run around a buck and a quarter, what was the radio, about two bills?

 

[Bruce]

Eric, this is my install https://jetboaters.net/threads/230-s...f-antenna-with-mooring-cover.2251/#post-40044

You can see that the GX1700 is installed under the dash. You can not see it but my Mente Marine ACS is installed in front of the throttles. Both have GPS receivers and work fine with the exception of the GX1700 often loosing GPS signal just after starting up. This may be because it has not yet acquired the signal. It sets off an alarm when it looses GPS signal. The alarm has never gone off except right after powering up.

 

[justason]

That's a neat unit, but you might want to consider mounting away from the stereo if possible. That would be the only concern I would have as far as electrical interference goes. It also calls for passengers to be at least 3' from the antenna to limit RF exposure.
Go ahead wire it up temporarily and try it close to the spot where you want it and see how it operates before you actually mount it. Check to see that the built - in GPS antenna will pick up satellites.
If you have a built in compass, check to make sure it doesn't interfere with its operation.
The worst thing that can happen is that you'll need a GPS antenna to pick up satellites. They run around a buck and a quarter, what was the radio, about two bills?

Standard Horizon is having a decent rebate thru July. Tacticalwholesalers had the unit for $188, less the $40 rebate...throw in some shipping.....$160-ish in hand.

right now the antenna is about brain height, I may ned to reconsider that detail....then again my breeding years are behind me, should might be ok.

 

[justason]

Eric, this is my install https://jetboaters.net/threads/230-s...f-antenna-with-mooring-cover.2251/#post-40044

You can see that the GX1700 is installed under the dash. You can not see it but my Mente Marine ACS is installed in front of the throttles. Both have GPS receivers and work fine with the exception of the GX1700 often loosing GPS signal just after starting up. This may be because it has not yet acquired the signal. It sets off an alarm when it looses GPS signal. The alarm has never gone off except right after powering up.

View attachment 21823

View attachment 21824

Hi Bruce. Exactly where I was considering. Are you saying your VHF is plumbed into the ACS, or just that the location of the ACS has clean reception, as well as the VHF ?

my backup location was face up on the wall below the throttles (near the kill switch and ballast fill). chair may hit it.

 

[Bruce]

The VHF and ACS each have their own GPS receiver. Both are located below fiberglass and both work fine.

On a side note, I want to congratulate the guy who named it "Attitude Control System". I had lots of fun with the kids and that box!

 

[Glassman]

Standard Horizon is having a decent rebate thru July. Tacticalwholesalers had the unit for $188, less the $40 rebate...throw in some shipping.....$160-ish in hand.

right now the antenna is about brain height, I may ned to reconsider that detail....then again my breeding years are behind me, should might be ok.

That IS a good price....less than I paid for a Standard Horizon handheld years ago....and now I can't find the battery charger and of course the battery is shot, so I'd say you made a smart move

 

[veedubtek]

Mine is in the exact same spot as Bruce's, but wired into my Lowrance. I haven't tested anything yet, so, take that for what it's worth. I assume it's using the GPS from the Lowrance and it won't be any kind of issue. With the antenna back on the transom, I can't foresee why it matters where the unit is mounted or what's near it?

 

[Bruce]

It would be optimal to mount the VHF antenna as far away from people as possible. Unfortunately that is not possible with our boats. I decided that it did not matter as our VHF radio transmits infrequently. I would guess that we have less than 20 minutes per year of exposure to radiation from the VHF antenna. This is something to think about if using DSC to track your friends. DCS will cause the radio to transmit more frequently.

 

[kthrash]

I put my Lowrance here: Tied to my Lowrance GPS. no interference at all.

 

[ArmyChief]

@justason ,

I bought the same unit a few weeks ago and will be testing it behind the driving station (dash). I believe I'm going to buy the all in one mike for the unit, and just drill the small hole for the mike jack cord in the dash.

For your antenna, you could build what I did. It was based of a thread @kthrash started some time ago. Using a bulletlines speaker tower mount.

Here is my finished mount. Due to my work schedule, I should be installing in two weeks.

 

[ArmyChief]

It would be optimal to mount the VHF antenna as far away from people as possible. Unfortunately that is not possible with our boats.

Well....there a a few things to consider. By fabricating a bracket..you can get it up high on the tower (farthest away and based off wave propagation, frequency and wattage would be safe). There are a few really GOOD reasons to get it high on the tower. One, higher SWR caused by the metal if the tower in the propagation lobe area. High SWR dramatically reduces transmit range AND CAN damage transmitter. Secondly, if you have metal in the lobe area, it affects the radiation pattern..again effecting those areas of transmission. Lastly, due to VHF being a Line of sight (LOS) transmission...the higher the antenna the greater distance.

 

[tdonoughue]

I mounted my VHF antenna just aft of the tower to the side of the boat. Not as high as optimal, but it is out of the way, farther away from metal, and does the job (I only boat lakes so far, so getting the optimal distance was not as critical as getting some distance).

For the GPS, I tied into the GPS that the boat had for the speedometer. See https://jetboaters.net/threads/installation-of-dsc-vhf-radio-to-the-stock-gps-antenna.518/

 

[sysinu]

Well....there a a few things to consider. By fabricating a bracket..you can get it up high on the tower (farthest away and based off wave propagation, frequency and wattage would be safe). There are a few really GOOD reasons to get it high on the tower. One, higher SWR caused by the metal if the tower in the propagation love area. High SWR dramatically reduces transmit range AND CAN damage transmitter. Secondly, if you have metal in the love area, it affects the radiation pattern..again effecting those areas of transmission. Lastly, due to VHF being a Line of sight (LOS) transmission...the higher the antenna the greater distance.

Thread Hijack, sorry - What you have there looks awesome for your antenna. I tried to do something similar but couldn't find anything that would match the thread layout for a tower clamp, so I used a drill press and grinder and made one that is very similar to what you have (mine looks less sleek, I think).

/threadhijack


As it relates to the OP's question, as long as you mount the GPS antenna to a fixed location, you're probably perfectly fine. That said, I would try to make sure you don't put it next to any wiring or near any of the grab rails/cleats/etc as they for certain will interfere. I have a GPS antenna installed in my truck for a nav unit and there is only a thin layer of plastic above where it originally was, but it always took a while to get signal and lock a location... I moved it 2" over (still hidden under the plastic) away from the frame and it made the world of difference.

 

[internationalmarinemike]

We install hundreds of the SH GX1700 units in a year and have yet to see issue with GPS not having a great signal. You should be good and of course even better of you follow the suggestions off the guys here.

On another note I looked at the tactical wholesalers pricing on that unit. I am not sure what they are doing but they are in violation of Standard Horizons distribution agreement. SH has a MAP price and no retailer is allowed to advertise that unit below $249.99. I would say jump on it while it lasts.

Mike

 

[ArmyChief]

I am not sure what they are doing but they are in violation of Standard Horizons distribution agreement. SH has a MAP price and no retailer is allowed to advertise that unit below $249.99. I would say jump on it while it lasts.

Mike

I bought mine that way. I believe they get away with it by making you place item in the cart to see the price. Some it's not being ADVERTISED at a price below...they are rolling the guidelines.

 

[justason]

interesting

We install hundreds of the SH GX1700 units in a year and have yet to see issue with GPS not having a great signal. You should be good and of course even better of you follow the suggestions off the guys here.

On another note I looked at the tactical wholesalers pricing on that unit. I am not sure what they are doing but they are in violation of Standard Horizons distribution agreement. SH has a MAP price and no retailer is allowed to advertise that unit below $249.99. I would say jump on it while it lasts.

Mike

interesting, I found it at several locations well under 249.99. tactical was by far the lowest

 

[ArmyChief]

I think Hodges Marine is where I got mine

 

[justason]

Thanks for the replies. I like what you did @ArmyChief @sysinu . It was important to me to be able to detach the antenna as a whole and leave the mount behind. I plagerized @kthrash method. @kthrash your install is very nice, my use will be minimal and i have that space reserved for my SAT radio and old man reading glasses......

I'm going to mount the antenna as high as the wire will let me and have to drill out larger wire run diameters in the tower, no issue there. Radio will go under the dash, should be fine......

Thanks everyone