RichardS
N/A
Why would I know or be interested in the regular price when I'm suggesting picking one up cheaply on eBay?
Richard
GPS input to DSC VHF radio
- Thread starter FairweatherDave
- Start date
Why would I know or be interested in the regular price when I'm suggesting picking one up cheaply on eBay?
Richard
Hoolie
Well-Known Member
Because on eBay there are always the chancers that are asking way above the going rate - check it out!
Stuff is often cheaper on Amazon than eBay, even from the same suppliers ... ...
Stuff is often cheaper on Amazon than eBay, even from the same suppliers ... ...
Last edited:
MikeCC
Well-Known Member
Yes but 2000 only available secondhand and 2200 has built-in GPS. Both options dearer than separate GPS receiver suggested in other posts.
RichardS
N/A
But I'm from Yorkshire so when I say "cheaply on eBay" you can be sure that I mean exactly that.
Richard
prv
Well-Known Member
But I'm from Yorkshire so when I say "cheaply on eBay" you can be sure that I mean exactly that.
In that case you don't want to fart around with multiplexers (especially since there aren't any of the one you suggest available for sale anyway), but go for this fella instead:
https://www.ebay.co.uk/itm/162784485815
£5.79, plus you'll also want a 5v DC-DC, like maybe this one, for a quid.
The chip is a uBlox 7, which is a perfectly good GPS. It will output the sentences you need by default, though I can't remember offhand the default baud rate - I suspect it's likely to be faster than the NMEA standard of 4800. However, the programming software is freely available to reconfigure this and many other aspects of the GPS, and will only need to be done once.
Pete
PaulRainbow
Well-Known Member
In that case you don't want to fart around with multiplexers (especially since there aren't any of the one you suggest available for sale anyway), but go for this fella instead:
https://www.ebay.co.uk/itm/162784485815
£5.79, plus you'll also want a 5v DC-DC, like maybe this one, for a quid.
The chip is a uBlox 7, which is a perfectly good GPS. It will output the sentences you need by default, though I can't remember offhand the default baud rate - I suspect it's likely to be faster than the NMEA standard of 4800. However, the programming software is freely available to reconfigure this and many other aspects of the GPS, and will only need to be done once.
Pete
My uBox 7 (backup GPS for the laptop) is 9600. It is currently on a shelf under the chart table, but it can see 14 satellites and OpenCPN works fine with it.
FairweatherDave
Well-Known Member
I've got to say this way of getting a a GPS signal is looking useful now. Went to the boat this morning and the cable linking the hand held was not passing the location to the VHF despite me setting the Output to NMEA.
So my question to Pete is how do I go about programming a uBlox chip? That may be a bit of a question too far
So my question to Pete is how do I go about programming a uBlox chip? That may be a bit of a question too far
PaulRainbow
Well-Known Member
I've got to say this way of getting a a GPS signal is looking useful now. Went to the boat this morning and the cable linking the hand held was not passing the location to the VHF despite me setting the Output to NMEA.
So my question to Pete is how do I go about programming a uBlox chip? That may be a bit of a question too far
No need to program it.
FairweatherDave
Well-Known Member
Cheers Paul. Will order one along with the power bit and see how I get on
rogerthebodger
Well-Known Member
How do you set the output speed to 4800.
I have one of these and use a Arduino to select the message and change the speed.
prv
Well-Known Member
You need the u-Center software from https://www.u-blox.com/en/product/u-center-windows , and a TTl-level serial adapter which will normally be a USB device. Lots of them available for communicating with Arduinos and suchlike.
Worth pointing out that I was going for the cheapest practical option as a response to Richard’s Yorkshireness. There are other options for a few pounds more with a better enclosed case and longer cable, and for a bit more still you can get ones that will run on 12v directly and come set to 4800bps. All likely a better option than trying to convert an unsuitable source just because it happens to already be on board. It’s not the 90s any more, basic GPS reception is not rare or expensive, it doesn’t need to be shared.
Pete
FairweatherDave
Well-Known Member
Cheers Pete. Haven't purchased anything yet . More googling.............
. More googling.............
PaulRainbow
Well-Known Member
Never changed any of the configuration of mine, the baud rate is automatic.
prv
Well-Known Member
Automatic based on what?
I didn’t need to change mine either, but that’s because it was connected to an Arduino and I could tell that to listen at the uBlox’s default 9600. But a standard marine VHF is going to be expecting 4800, and the uBlox has no way of knowing that that’s what it should output except by manual programming.
Pete
rogerthebodger
Well-Known Member
That's what I was thinking.
PaulRainbow
Well-Known Member
Mine works perfectly OK on the laptop, no matter what i set the baud rate to in OpenCPN, Polar View or the laptops port settings. So either the uBlox is automatically adjusting the baud rate, or the laptop and/or its software is making adjustments.
FairweatherDave
Well-Known Member
I've done a fair bit of googling and I'm struggling to find anything cheap-ish that comes set to 4800bps.........
I can go the techie route and lean on a friend if I have to but the cheapest thing seems to be this sort of thing
GlobalSat BR-355S4 GPS Receiver (Black)
but I'm not sure how I would get power in
or this
https://www.amazon.co.uk/GlobalSat-BU-353-S4-Receiver-SiRF-Black/dp/B008200LHW/ref=dp_ob_title_ce
which has a USB connection.
RichardS
N/A
Ah yes ..... but I also wanted to take the distress output from the VHF which is at 4,800 and pass that back to the muxer to convert it to 38,400 so I could send it to the chartplotter (set at 38,400 to receive the AIS data) and there's is no other simple way to achieve that.
Not just Yorkshire but as sharp as Sheffield steel.
Richard
FairweatherDave
Well-Known Member
Apologies for double posting but in case anyone finds this useful my friend finally cracked the problem and wrote this....
Using a ublox-7 GPS with a XM-DSC VHF radio.
3 issues with connecting these;
1.) Radio expects RS422 differential signalling rather than the TTL RS232 output by the ublox-7, so you need a TTL->Rs422 converter. These are £2.50 on eBay
2.) Radio expects 4,800 baud, but most UBlox default baud-rate is 9,600, and whilst you can change I with u-center the cheap clone ublox-7 units on ebay do not have flash so will revert back to 9600 on power down, even if you save defaults.
So I used a spare Pic32MX150F128D with 2 UART inputs to make a quick and dirty 9600 - 4800 baud converter. This may seem like it wont work , but there is plenty of time to send the packet at 4800 as the inter packet gap is quite big. Any Pic with 2 UARTS will do, set the input UART to 9,600 baud and the output to 4,800. You will need to receive into a buffer on interrupts and then write out the data in a tight loop (while there is data in the buffer)
3.) You need a 12-5V converter to power it all
Out in the open will pick up a signal in about 5 minutes and then stay locked on.
My version also echos the data to the u-center (by looping the RS422 input back and grabbing the 4,800 RX from the TTL-RS422 converter) S/W. This will plot your course for you, as well as keeping the XM-DSC happy.
Using a ublox-7 GPS with a XM-DSC VHF radio.
3 issues with connecting these;
1.) Radio expects RS422 differential signalling rather than the TTL RS232 output by the ublox-7, so you need a TTL->Rs422 converter. These are £2.50 on eBay
2.) Radio expects 4,800 baud, but most UBlox default baud-rate is 9,600, and whilst you can change I with u-center the cheap clone ublox-7 units on ebay do not have flash so will revert back to 9600 on power down, even if you save defaults.
So I used a spare Pic32MX150F128D with 2 UART inputs to make a quick and dirty 9600 - 4800 baud converter. This may seem like it wont work , but there is plenty of time to send the packet at 4800 as the inter packet gap is quite big. Any Pic with 2 UARTS will do, set the input UART to 9,600 baud and the output to 4,800. You will need to receive into a buffer on interrupts and then write out the data in a tight loop (while there is data in the buffer)
3.) You need a 12-5V converter to power it all
Out in the open will pick up a signal in about 5 minutes and then stay locked on.
My version also echos the data to the u-center (by looping the RS422 input back and grabbing the 4,800 RX from the TTL-RS422 converter) S/W. This will plot your course for you, as well as keeping the XM-DSC happy.