Replacement antenna for Philips Mk 10 Navigator GPS

[chrischand]

I have a perfectly reliable but rather ancient Philips GPS built into my Nav Station. Unfortunately the "Globe Antenna" case is cracked and the unit no longer works. I have made enquiries about buying a replacement antenna and been quoted £400 ! For this price I can of course get a new combined GPS / plotter. I would much rather replace the antenna, if I can, as the GPS is already plumbed into the auto pilot and a plotter.

Any suggestions gratefully received !

 

[Gwylan]

Interested to know what reaction you get - have a similar problem. Maybe it will work with any other aerial?

 

[AntarcticPilot]

Sadly, I think you are out of luck. The antenna is likely to be matched to the receiver, especially if it is a rather old model. Antenna design has advanced rapidly - even a few years ago, a GPS antenna that would fit in a phone was unthinkable, and I remember the awe and wonder of the first hand-held Trimble GPS! You are unlikely to find an antenna that will work with the GPS on the market; it would be a tiny market - that's why you are being quoted a massive price for what is probably "new old stock!" You're paying the rental of a shelf for however long it is since the equipment was current.

The other thing to bear in mind is that your receiver is probably a bit primitive by modern standards; for example, it may be 6 channels or less - 12 is the norm these days. That means that fixes are not so good, and under marginal conditions (i.e. poor GDOP), you will get worse fixes. Maybe not really a problem, but theoretically a bad thing. It will also be slow acquiring a first fix compared with modern equipment.

How does your GPS interface with the rest of the navigation gear? If it is a NMEA interface, then pretty much any modern GPS will interface with it; even Garmin's cheapest. If it is something else (i.e. a proprietary interface), then once again, you are out of luck.

I am afraid that electronics cannot be maintained forever - advances in technology and changes in fashion mean that old equipment will die when parts are no longer readily available.

 

[lw395]

Disconnect the antenna, switch on the receiver and carefully measure the voltage at the antenna socket. On many receivers, there is +5 or plus 3 and a bit volts on the centre pin.
If this is the case, then most gps antennas will work. I have successfully used cheap ones intended for car use, bought from bay for about £10, sometimes less. They are intended to magnetically mount on a car roof. Remove the magnets to avoid compass issues. Mount on a flat plat at least 9 inches across, because this ground plane affects the tuning of the antenna. To try it out just magnet the antenna onto a biscuit tin lid. For permanent install, I used a square ali plate with the corners rounded off. waterproofed it with some good quality RTV. Was working fine 18months later when I sold the boat.
Try to buy an antenna with a bnc connector, as the cable they come with is often horrible to change connectors on!
Worth a try.
Buying a new Garmin system with charts etc is probably good value now, but at the time I was negotiating a sale to someone who had his own ideas so I did not want to spend the money!
PS I always carry a backup GPS (if going out of sight of land) and I'm basically a paper chart navigator.

 

[chrischand]

Advice

Thanks for your comprehensive replies. My kit is connected via NMEA so I think I am off to spend a few bob on a basic garmin gps , followed by a bit of carpentry to tidy things up !