Garmin GPSMAP 640 - Page 2 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #11  
Old 03-21-2009
Senior Member
 
Join Date: Jul 2008
Posts: 140
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
floatsome is on a distinguished road
I don't get this spec: "Supports DSC (displays position data from DSC capable VHF radio)" -- shouldn't that be "to" not "from"? It is NMEA 0183-capable, and I would have thought the 620 could be connected to a DSC radio to supply the radio with position data.
Reply With Quote Quick reply to this message Share with Facebook
  #12  
Old 03-21-2009
Senior Member
 
Join Date: Jul 2008
Posts: 140
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
floatsome is on a distinguished road
The manual is online: http://www8.garmin.com/manuals/GPSMA...nersManual.pdf.

The 640 looks interesting, based on my quick read of that manual. Some comments/uncertainties:

1. Close to my personal sweet spot -- Can be used on our small sailboat for local summer coastal cruising augmented by laptop down below, and in the car or on vacations (portable). See also point 11.
2. Price point is up there - phew. Can get much larger screens from other manufacturers for less, but Garmin does make nice stuff. The price makes me think twice, though.
3. Can integrate XM satellite weather data.
4. Nice integration of AIS and other position data from a DSC radio, at least on paper, and presuming other people use their DSC radios.
5. Not clear to me how to network this device with a DSC radio and a wind meter, at a minimum. The 640 is NMEA 0183-capable, so is the idea to bus the 640 with other devices, presuming the 640 can supply the GPS sentences required by the other devices? Is NMEA 0183 enough these days, now that NMEA 2000 is out?
6. Screen is small, but I've been living with GPSMap 76C for years now, the 640 screen is twice the size, and that size of screen has found a big consumer automotive market, so it works for many.
7. Nice options for connecting to a computer for planning: SD card (though it is buried under the battery) and USB mini-port.
8. Short battery life compared to the 76C, so will need to ensure DC power is available.
9. I am not clear on whether the 640 can send position data to the DSC radio.
10. Garmin insists on calling intended tracks "course", and using "track" for "breadcrumb trail of past GPS fixes representing tracks made good", and using "heading" instead of "course being steered", but that's just my own pet peeve, shared by the tiny minority of consumer navigators, and I can work around it.
11. Speaking of consumers, this thing is a cool toy for the average recreational boater: decent marine navigation aid, but capable of good automotive navigation, displaying photo slide shows, and listening to XM audio by patching to exertnal speakers. They know their market.

On a serious long range cruise and bigger boat, I'd want a bigger screen and more chartplotting/networking capability, but I've got this product on my think-about list for our purposes.

Last edited by floatsome; 03-21-2009 at 05:52 AM.
Reply With Quote Quick reply to this message Share with Facebook
  #13  
Old 03-21-2009
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
A good full-feature DSC Class D VHF radio will have both NMEA 0183 in and out.

NMEA IN
—so that it can broadcast your position if you call for help.

NMEA OUT
—so that if someone else calls for help, it can plot them on your chart plotter... so you know where they are according to their DSC-broadcasted position.

Many of the low-end VHF units do not support this feature, but it is a good feature to have on your radio. For instance, if you call up a friend via their MMSI, you can see where they are in relation to where you are if they respond with a position update. If you're out fishing and want them to know where you're catching all the fish, but not have to announce it via voice....DSC is a good way to do it.


Quote:
Originally Posted by floatsome View Post
I don't get this spec: "Supports DSC (displays position data from DSC capable VHF radio)" -- shouldn't that be "to" not "from"? It is NMEA 0183-capable, and I would have thought the 620 could be connected to a DSC radio to supply the radio with position data.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #14  
Old 03-22-2009
Senior Member
 
Join Date: Jul 2008
Posts: 140
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
floatsome is on a distinguished road
Quote:
Originally Posted by sailingdog View Post
A good full-feature DSC Class D VHF radio will have both NMEA 0183 in and out.
I know that (taught the course for several years), but I did not see in the literature that the 640 is able to supply the radio with the host boat's position data in order to transmit the boat's position digitally, unless I missed something. It only talked about the 640 receiving position data from other boats via the radio receiver. Maybe that single NMEA link is two-way, and the literature simply did not specify it, or I missed it.
Reply With Quote Quick reply to this message Share with Facebook
  #15  
Old 03-23-2009
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
Floatsome—

If the VHF is DSC capable, it has to accept NMEA information in at a minimum, so that the DSC broadcast can send GPS based LAT/LON information during a distress call. The better DSC-capable radios, like the Icom M504 I use and unlike the Raymarine Ray54 VHF I used to use, can send GPS LAT/LON information to the chartplotter, so that an icon/waypoint for the sender's location appears when you receive it. Any GPS that is NMEA 0183 capable will provide the LAT/LON information to a DSC-capable VHF that is properly connected to it.

NMEA, being a serial protocol is a unidirectional protocol for each set of wires... there is always an NMEA data out and a separate NMEA data in. They never have both connections running over the same exact wire—they can't—RS-232/422 TX data lines can't receive data, and RS-232/422 RX data lines can't transmit data.

Some of the older chartplotters, which were designed before DSC-capable VHFs were common, can not accept the DSC-generated NMEA LAT/LON data and plot it on the screen. The software in them doesn't support that function. This is probably why the manual emphasizes this point—that it can supply the radio with LAT/LON position data is assumed.


Quote:
Originally Posted by floatsome View Post
I know that (taught the course for several years), but I did not see in the literature that the 640 is able to supply the radio with the host boat's position data in order to transmit the boat's position digitally, unless I missed something. It only talked about the 640 receiving position data from other boats via the radio receiver. Maybe that single NMEA link is two-way, and the literature simply did not specify it, or I missed it.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #16  
Old 03-23-2009
Senior Member
 
Join Date: Jul 2008
Posts: 140
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
floatsome is on a distinguished road
Mystery partly resolved: the manual says nothing about how the 640 physically connects to an NMEA network, but this does: http://www8.garmin.com/manuals/GPSMA...structions.pdf. The 640 has both TX/RX connections, but they appear to be made through the marine-mount bracket. I can't tell if there is a connector in the 640 that mates with a connector in the bracket and the user wires the network into the bracket's cable, or if there are user-accessible NMEA ports on the 640 itself.
Reply With Quote Quick reply to this message Share with Facebook
  #17  
Old 03-23-2009
sailingdog's Avatar
Telstar 28
 
Join Date: Mar 2006
Location: New England
Posts: 43,291
Thanks: 0
Thanked 11 Times in 11 Posts
Rep Power: 13
sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice sailingdog is just really nice
It looks like the bracket acts as a cable connection, so I doubt there's a separate NMEA 0183 interface on the unit.
__________________
Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
Reply With Quote Quick reply to this message Share with Facebook
  #18  
Old 03-23-2009
arisatx's Avatar
Senior Member
 
Join Date: Sep 2004
Location: Evanston
Posts: 299
Thanks: 4
Thanked 3 Times in 3 Posts
Rep Power: 11
arisatx is on a distinguished road
Quote:
Originally Posted by sailingdog View Post
It looks like the bracket acts as a cable connection, so I doubt there's a separate NMEA 0183 interface on the unit.
Got one! There's a 24 "pin" connector on the bottom of the 640 that mates with the contacts on the mount. Having owned the 276c for many years now and enjoying the portability between car, bike and boat (incl charter boats), I have been waiting for this new gen 640. The user interface and the touch screen are taking some time to get used to. And it appears that if you want XM Radio or XM Weather, you have to connect the XM antenna via USB port (not the aforementioned 24 pin connector to the NMEA 0183 interface) so it does not seem to lend itself to a "permanent" xm install.

I have not yet obtained the g2Vision SD card so can't comment on that. It won't replace a full chartplotter onboard, IMHO, but seems like a good successor to the 276c line.

Oh and if you hunt around, you can find the units for around $980 as I recall.
__________________
Regards,
Ted
V42#186
s/v Little Wing
Reply With Quote Quick reply to this message Share with Facebook
  #19  
Old 03-24-2009
Senior Member
 
Join Date: Jul 2008
Posts: 140
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
floatsome is on a distinguished road
Quote:
Originally Posted by arisatx View Post
...it appears that if you want XM Radio or XM Weather, you have to connect the XM antenna via USB port (not the aforementioned 24 pin connector to the NMEA 0183 interface) so it does not seem to lend itself to a "permanent" xm install.
Very helpful - thanks. About the XM connection: would a little modification with a Dremmel tool give access to the USB port while the unit is mounted in the bracket?

I did that years ago with my old 76C bracket, and the modification has been working very well over the years (allows both power plug and USB connection while in the bracket). It exposes the wiring to weather risk, however, since of course the little black rubber plug has long since vanished.

Quote:
Originally Posted by arisatx View Post
...won't replace a full chartplotter onboard...
I agree, but what is your rationale for this comment? It seems to me that larger consumer-grade chartplotters tend to be just bigger versions of the 76 and 276 families, without features that make it easy to modify waypoints and routes the way one can on a laptop using Mapsource or other PC nav programs. Professional chartplotters have many more features that make true electronic plotting and planning very easy, but that's still out of the league of most of us pleasureboaters, I suspect. And of course bigger consumer-grade chartplotters allow integrated radar/electronic chart display, which the 640 does not. (By "chartplotter" I mean a GPS display unit dedicated to the purpose, as opposed to a laptop/desktop configure for chartplotting).

Last edited by floatsome; 03-24-2009 at 06:26 AM.
Reply With Quote Quick reply to this message Share with Facebook
  #20  
Old 03-24-2009
arisatx's Avatar
Senior Member
 
Join Date: Sep 2004
Location: Evanston
Posts: 299
Thanks: 4
Thanked 3 Times in 3 Posts
Rep Power: 11
arisatx is on a distinguished road
Floatsome:

re: XM connection via USB, you won't need to pull out the Dremel to perform surgery on the mount. USB can be connected when the 640 is in the mount - it's just another connector dangling there, in addition to an XM radio audio out - wish they could've incorporarted this all into the multi-connector.

re: my comment about not replacing a full chart plotter, it doesn't overlay radar, it's not N2K - but as you point out, then we're in another price category.

But for it's purpose, I'm pretty happy with the 640 so far.
__________________
Regards,
Ted
V42#186
s/v Little Wing
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Product Reviews Cruisingdad Gear & Maintenance 121 05-27-2014 02:02 PM
chartplotter/mfd swing arm mount janders Gear & Maintenance 6 12-23-2008 02:12 PM
'08 Garmin g2 Blue Chart worth it as update to preloaded '06 g2 in my GPSMap 498? fendertweed Gear & Maintenance 0 08-16-2008 01:17 PM
Handheld Garmin GPSMAP 76 Pamlicotraveler Gear & Maintenance 6 10-01-2006 06:05 PM
Garmin GPSMAP 60Cx ...? CS...? C? geary126 Gear & Maintenance 3 08-01-2006 09:54 AM


All times are GMT -4. The time now is 09:51 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.