GPS Antenna Quandary

[nhodgson]

Hunter Family, assistance requested please.

I think I may have to replace the RS120 GPS antenna with an RS125 version.

1. Who's done it????
2. How did you do it???
3. Did you use the RS120 cable to pull the new RS125 cable through the arch??
4. Where on earth does that cable run? My current puck is on the SBD davit top which is factory integral to the stainless steel arch.......
5. How does the signal get to the (in my case) C80 MFD at the helm station.....Seatalk???

Hair is being pulled out.....


Neil

 

[jssailem]

Hi Neil.
Sounds like you’re in the thick of a project.
I am curious why you are going to use a RS125. The current Raymarine products are the RS150 (flat pancake), the GA200 and the RS 130 (which look like a mushrooms).

Are you installing a new chart plotter? Did the other unit fail?

It would seem usual to be able to use the old cable as a messenger cord. Should work unless the installer used some sort of wire tying plan. This would have been the dealer who commissioned the boat or a previoous owner, not the Hunter manufacturing plant.

 

[nhodgson]

Hi Neil.
Sounds like you’re in the thick of a project.
I am curious why you are going to use a RS125. The current Raymarine products are the RS150 (flat pancake), the GA200 and the RS 130 (which look like a mushrooms).

Are you installing a new chart plotter? Did the other unit fail?

It would seem usual to be able to use the old cable as a messenger cord. Should work unless the installer used some sort of wire tying plan. This would have been the dealer who commissioned the boat or a previoous owner, not the Hunter manufacturing plant.

Thanks for the reply John.

My C80 is working fine, although the date is locked in 2005, probably due to the antenna. I thought the 125 would be a good enough upgrade so I didn't have to install a backbone and Seatalk - Seatalkng bridge. My local electronics guru suggested it, and he's been spot on up to now.

I am going back to the boat tomorrow to see if I can trace the cable somehow, but I share your concern there may be a cable tying system in place preventing me from using it as a tail.

Do you happen to know how the current antenna would be connected to the C80? It's certainly not NMEA0183, as I am using that for AIS installation. I have to presume it connects with the small push on fittings on one of the instruments (not the autoplitot) and then goes to the C80 through seatalk connections.

Neil

 

[MFD]

Not sure what the issue is with your RS120, but I am pretty sure they have a battery inside that can die after 10 years or something.
One of those lithium hockey puck type batteries.

 

[Davidasailor26]

GPS counts time within “epochs” - basically sets of 1024 week blocks of time through which the the GPS system increments. Older receivers receive the “current” date and assume that it must be 2005, because that was the date when the week counter matched what it’s receiving in the epoch it knows about. A quick Google suggests that the RS120 was never updated for the latest epoch (which started in 2019), but that the RS125 may have been. The 125 is still a very old and unsupported model so depending on whether the one you buy received the update you may still have challenges.

 

[marcham]

RS125 had it's own list of issues.... you probably won't get an accurate date with that one either. I'm just about to replace my 2002 vintage Raymarine GPS receiver (RS 12??) with a Garmin 24XD hooked up to my STNG / ST1 hybrid network. It's relatively affordable and has the added benefit of providing magnetic heading.

Why not just update with an NMEA 2000 GPS and then use a STNG-ST1 converter ?

It will most likely not be a straight pull. You'll need to open every access port in between the current antenna and wherever it connects to the plotter/ST1 network.

 

[MFD]

I have a C120 plotter and one of the old RS12x (0 or 5, can't recall).
It only feeds the C120, nothing else. I have an entirely separate/duplicate system that is newer.
With the bad battery in the RS12x, and if shutdown for a long time, it will take 10-15 minutes to get a fix. My understanding is from the bad battery. Basically it has no starting reference point from last time it was running to help get a fix faster.
I bought a replacement battery a couple years ago but it ended going into my car key fob after sitting around for a couple months.

Anyway - if I was going to go through the effort to pull wire and replace the RS12x, I would definitely go with something new/modern for sure.