GPS sources for radio etc

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bromleybysea

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I currently source position information for my DSC radio and Yeoman plotter from an old Garmin 120 GPS unit but I think it may have died. It's being tested at the moment, but on the basis that I will probably have to replace it it would be helpful to have views on the best and cheapest alternative. I don't want to run a feed from my plotter as I like to have independent systems. I guess the ideal would be a GPS antenna that can be powered from the boats 12v supply, but all the GPS pucks I have seen are either powered trough the cable from a dedicated unit or are 5v for use with a laptop. Any suggestions most appreciated.
 
bromleybysea said:
I currently source position information for my DSC radio and Yeoman plotter from an old Garmin 120 GPS unit but I think it may have died. It's being tested at the moment, but on the basis that I will probably have to replace it it would be helpful to have views on the best and cheapest alternative. I don't want to run a feed from my plotter as I like to have independent systems. I guess the ideal would be a GPS antenna that can be powered from the boats 12v supply, but all the GPS pucks I have seen are either powered trough the cable from a dedicated unit or are 5v for use with a laptop. Any suggestions most appreciated.
Click to expand...

If you're handy with electronics, you can cannibalise a USB variant, but you'd need to make a voltage regulator circuit to drop from 12~15V down to 5V. USB is serial and many of the devices can send NMEA signal - check first! You're probably looking around £30 plus power supply components. I did this with the Cobra VHF I have - chop the USB connector off, waterproof box for power & cable terminations etc... There are loads of cheapish USB receivers using SirfIII chips. :D I used one similar to this: http://www.ebay.co.uk/itm/Globalsat...ics_GPSSystems_GPSSystems&hash=item3386ac5347
 
A 12v to 5v converter! It's all of three components if you want to solder your own, or forumite Angus Macdoon sells one ready-made and with easy-to-wire terminals.

EDIT: You don't want a USB one. Despite the "Serial" in the name, it's not a serial connection as used for NMEA.

Pete
 
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prv said:
A 12v to 5v converter! It's all of three components if you want to solder your own, or forumite Angus Macdoon sells one ready-made and with easy-to-wire terminals.

EDIT: You don't want a USB one. Despite the "Serial" in the name, it's not a serial connection as used for NMEA.

Pete
Click to expand...

I agree.
If the baud rate is OK this:
http://www.ebay.co.uk/itm/New-Ublox...al_Components_Supplies_ET&hash=item51bb4c6d06
might be a good option for DIY?

I've used the ublox modules, they just need 5V, an aerial, and a couple of transistors to invert the data for rs232.
They are very good, sensitive, intelligent GPS's.
 
prv said:
A 12v to 5v converter! It's all of three components if you want to solder your own, or forumite Angus Macdoon sells one ready-made and with easy-to-wire terminals.

EDIT: You don't want a USB one. Despite the "Serial" in the name, it's not a serial connection as used for NMEA.

Pete
Click to expand...

USB is serial data (Universal Serial Bus) - and auto negotiates. I used one like in my link, which if you read supports NMEA183. Mine's lasted for 4 years! :)
 
lw395 said:
If the baud rate is OK this:
http://www.ebay.co.uk/itm/New-Ublox...al_Components_Supplies_ET&hash=item51bb4c6d06
might be a good option for DIY?
Click to expand...

This: http://www.ebay.co.uk/itm/NEW-Globa...ics_GPSSystems_GPSSystems&hash=item54075aa99d
Plus this: http://www.yappelectronics.co.uk/GPPS.htm

Would be better. (Or skip the YAPP box, it's only a voltage regulator and a couple of capacitors).

lw395 said:
They are very good, sensitive, intelligent GPS's.
Click to expand...

Caring, good sense of humour...? :p

Pete
 
rbcoomer said:
USB is serial data (Universal Serial Bus)
Click to expand...

Samuel Morse's telegraph was also serial data, but it won't connect to my iPod. Saying "it's serial, therefore it's compatible" is a nonsense.

If you have a device that happens to auto-negotiate USB or RS232 (once common in mice; I can believe a GPS puck might do it) then great, but it's not the norm. Telling people that they can wire USB devices, in general, into systems speaking RS232 (or similar) is a recipe for a lot of confusion and disappointment.

Pete
 
prv said:
Samuel Morse's telegraph was also serial data, but it won't connect to my iPod. Saying "it's serial, therefore it's compatible" is a nonsense.

If you have a device that happens to auto-negotiate USB or RS232 (once common in mice; I can believe a GPS puck might do it) then great, but it's not the norm. Telling people that they can wire USB devices, in general, into systems speaking RS232 (or similar) is a recipe for a lot of confusion and disappointment.

Pete
Click to expand...

I didn't - I read the supported spec of the device. :) Defaults to NMEA183 at 4800 baud! I also know the spec of USB and serial interfaces having worked with electronics since the age of 12 when I started repairing electronics. Have you never encountered a USB to PS2, PS2 to Serial or USB to Serial adaptor for computer mice etc? There's no wizardry involved in the adaptors, just the device in either end that negotiates the protocol required...

Either way, I'd go with your suggestion - later chip and £3 cheaper! :encouragement:
 
bromleybysea said:
I currently source position information for my DSC radio and Yeoman plotter from an old Garmin 120 GPS unit but I think it may have died. It's being tested at the moment, but on the basis that I will probably have to replace it it would be helpful to have views on the best and cheapest alternative. I don't want to run a feed from my plotter as I like to have independent systems. I guess the ideal would be a GPS antenna that can be powered from the boats 12v supply, but all the GPS pucks I have seen are either powered trough the cable from a dedicated unit or are 5v for use with a laptop. Any suggestions most appreciated.
Click to expand...

This puck is 12volts and easy to connect.

http://www.ebay.co.uk/itm/Lowrance-...tEquipment_Accessories_SM&hash=item35c517db22
 
rbcoomer said:
I didn't - I read the supported spec of the device. :) Defaults to NMEA183 at 4800 baud!
Click to expand...

I guess the 4800baud is a clue that that particular one does real serial, but I wouldn't draw any conclusions from the NMEA part. Could easily just mean that the data is emitted (via whatever protocol) in the NMEA sentence format. I could hand-write NMEA sentences on slips of paper and post them - it's still "NMEA output", but it's no good to your radio.

rbcoomer said:
Have you never encountered a USB to PS2, PS2 to Serial or USB to Serial adaptor for computer mice etc? There's no wizardry involved in the adaptors, just the device in either end that negotiates the protocol required...
Click to expand...

Yes, and if you try one on a modern USB mouse it's quite likely not to work with your PS/2 computer, because they've given up including the compatibility hack since nobody uses PS/2 any more. The "negotiation" is in no way a part of being a USB device, it was just a clever trick to let a dual-protocol mouse work with a wider range of computers back when USB wasn't yet ubiquitous.

You still shouldn't go round misleading people that USB and RS232 are more or less interchangeable.

Pete
 
prv said:
....


Quote Originally Posted by lw395 View Post
"""They are very good, sensitive, intelligent GPS's.""""
Caring, good sense of humour...?

Pete

Caring, good sense of humour...? :p

Pete
Click to expand...
Only if you talk nicely to them in their own language!, and at their own speed.
They can get moody otherwise.
Some of the ublox modules have USB built in too, ther may be some which only have USB, no 'raw' serial.

With a lot of these things, the RF connectors are a fiddle, tiny, hard to work with without the special tools, and expensive to buy in small quatities, so avoiding the need is good.
Also remember these ceramic patch antennas generally epect to be sat on a certain area of ground plane. Those intended for car roof use will like anythig over about 4 inch square, those used in handheld gear may be matched to a particular small size, it tunes the resonance of the antenna.

The YAPP 'couple of capacitors' can be important.
 
I have just done exactly this using a GlobalSat USB and advice from this forum. The GlobalSat was just over £40 (do NOT get the USB one) and I made up a 5v supply with a few components bought on line. Works like a good 'un and was quite good fun to do (I know ... that's very sad!).
Morgan
 
 
bromleybysea said:
Unfortunately, Angus McDoon no longer produces the 12v supply module, but did suggest pulling apart a car USB adapter. Or would something like this do the job: http://http://www.eachbuyer.com/dc-dc-converter-regulator-12v-to-5v-3a-step-down-power-supply-buck-module-p175604.html?currency=GBP&utm_source=google&utm_medium=CSE&utm_content=%5BCar+Accessories%5D&utm_campaign=%5BPLA%5DEngland(EN)&gclid=CK_dkOmoir4CFWT4wgodfgYAbA
Click to expand...

Oh that's a good idea! They weren't invented when I came up against this problem about 10 years ago. I ended up using a 5V "puck" and powering it from 4 AA cells in series (it didn't seem to mind getting 6V). One set would last me half a season.
 
Until I sold my Yeoman Sport plotter recently, I used a Garmin12 handheld unit mounted on a suction RAM mount in the saloon which fed the Yeoman just fine. The G12 is heavy on double AA batteries as it is very old tech but it did the trick faultlessly as I had an electronics shop make up a power & data pickup using a standard cigarette lighter plug with a small junction box carrying an in-line 'quickblow' fuse to protect against any engine startup spikes, as of course I drew constant power from the ship's battery. This box of course was optional but for just a few £'s it made an elegant solution to the power & data issues which both devices needed.

Now, I hope this helps perhaps and for reasons I have forgotten (but probably my OTT 'belt & braces' attitude) I had 3 of these G12's- now down to 2 following aforesaid sale and you are welcome to one of the remaining ones for a reasonable sum BUT I see you now hate Bromley :) so you would perhaps have to keep your head down and make a flying visit here to collect?

I've just found this http://cgi.ebay.co.uk/ws/eBayISAPI....akeTrack=true&ssPageName=VIP:watchlink:top:en
and frankly it's worth about half of what bidders have offered so far!
 
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