Paper Charts or Just Electronic

[transmitterdan]

Originally Posted by Simi 60

Seiwa

I have no experience with Chinese GPS receivers. But if this is the antenna (http://www.seiwadirect.com/Manuals/UX0GPg00xx.pdf) I have some doubt about their design prowess. The NMEA data is transmitted over a 10 or 15 meter cable using single ended 5V serial data. It is not meeting specification of either RS-232C (as they claim) nor is it meeting NMEA-0183 electrical interface standard which it should. Such a 5 volt single wire serial interface on a ship is bound to have lots of problems.

There is a reason the NMEA standard interface is a balanced two wire differential signaling scheme. That antenna not designed for a boat.

[lordgeoff]

Originally Posted by jackdale

I use a lead line to measure the depth under my rudder when I anchor stern-to shore.

Do you think I have have a depth sounder on the stern?

I prefer to nose into the bank bow first as bow first my draught around the transponder is only inches. Once I ascertain the depth is sufficient and safe I do the med mooring normally.
A lead line or depth sounder on my stern would only confirm I have just compromised my rudder.

[Simi 60]

Originally Posted by transmitterdan

I have no experience with Chinese GPS receivers. But if this is the antenna (http://www.seiwadirect.com/Manuals/UX0GPg00xx.pdf) I have some doubt about their design prowess.

No, that is not the antenna.
This is.

https://www.yachtbits.com/seiwa-gps-...oof-50-channel

Seiwa GPS antenna is a compact, accurate and completely waterproof Satellite Differential GPS Receiver:

50 channels WAAS (North America), EGNOS (Europe), MSAS (Asia).
Its NMEA 0183 output allows connection to any SEIWA instrument.
The Antenna comes with a 10mt (3') cable.

[Simi 60]

Originally Posted by Alan Mighty

Precisely because it is a USA GPS only device.

If, like a relatively inexpensive USB GNSS puck, it polled a greater number and variety of satellites (e.g. GLONASS, BeiDou, and QZSS) it would be more accurate.

Anyone telling you differently is just unaware of your location (i.e. longitudes that benefit from coverage from the PRC BeiDou satellites and the Nippon QZSS) and the accuracy thus gained.

Yep.
My handheld garmin , gps only, takes forever to get a fix as well.
$45 android mobile phone has one in less than a minute.

[transmitterdan]

Originally Posted by Simi 60

Yep.
My handheld garmin , gps only, takes forever to get a fix as well.
$45 android mobile phone has one in less than a minute.

That’s because your phone knows it’s approximate location so it doesn’t have to wander all over the earth looking for a satellite combination that matches. But that has nothing to do with GPS reliability or accuracy.

[Simi 60]

Originally Posted by transmitterdan

That’s because your phone knows it’s approximate location so it doesn’t have to wander all over the earth looking for a satellite combination that matches. But that has nothing to do with GPS reliability or accuracy.

Not when its out of mobile range it doesn't.
And how do you explain my $100 android tablet that does the same?
It has no sim card and can do it without a data connection.

[transmitterdan]

Originally Posted by Simi 60

No, that is not the antenna.

This is.

It looks the same. And it almost certainly has the same crummy 5V single ended serial port on a too long cable. 33 feet is too long to reliably transmit single ended 5V data. Almost everything on or near the boat can interfere with it. Radar, LED lamp drivers, SSB, broadcast AM radio and a host of other interference sources could cause the problems you have reported.

[transmitterdan]

Originally Posted by Simi 60

Not when its out of mobile range it doesn't.
And how do you explain my $100 android tablet that does the same?
It has no sim card and can do it without a data connection.

Your Android phone consumes at least 20X the power of a handheld Garmin GPS 76. Maybe 100X. Speed = power consumption. It’s all a trade off.

[Simi 60]

Originally Posted by transmitterdan

It looks the same. And it almost certainly has the same crummy 5V single ended serial port on a too long cable. 33 feet is too long to reliably transmit single ended 5V data. Almost everything on or near the boat can interfere with it. Radar, LED lamp drivers, SSB, broadcast AM radio and a host of other interference sources could cause the problems you have reported.

Sounds like excuses, especially as we would very rarely have led lights or radar on during the day, have no ssb radio and certainly dont listen to am radio.

Also any other manufacturer i look at have 10m/33ft cables as well.

[Simi 60]

A quick google shows that others in the southern hemispheres (police tracking anklets, drones, fitbits and and and) also say they have GPS dropping out issues.

Seems to me its a GPS in the southern hemisphere issue, not chinese receiving antennas as you claim.
All my other Chinese antennas no matter how cheap, work incredibly fast an accurately, as long as they don't rely on GPS alone.

[transmitterdan]

GPS is exactly the same in Northern and Southern Hemisphere. Coverage gets weaker at higher latitudes both north and south. Australia is covered about the same as the northern US.

Long cables require the right electrical signal design. NMEA-0183 is designed to go >30M. 5 V single ended is designed to go about 1 meter.

[barryglewis]

Originally Posted by Pelagic

I think the bottom line from this long long discussion is to carry navigational aids that you are comfortable using.

Senior navigators have gone thru the transition from DR-Celestial/LORAN/TRANST to GPS so have this built in training redundancy with paper charts and a better comfort level with using independent off-grid navigation.

New Navigators have a choice:

1 Focus on modern aids with equipment redundancy and updated Data/Programs

2.Same as #1 but with "get home" basic old school navigational methods that probably will hardly ever be used and thus forgotten ... A paper chart is needed if boat is damaged and without power.

#3 A new navigator who treats navigation like meteorology as a challenge and a hobbie to improve skills for personal satisfaction.

To be honest, I would happily trade my celestial training and experience for better computer programing skills to follow all the OpenCPN gibberish! [emoji4]

That stuff gives me a headache!

As a "senior" navigator, albeit having missed out on Loran and transit I worry about new navigators using celestial nav and compass as their backup if they lose GPS.
The mindset needed to cope with infrequent fixes with areas of possible posn often several miles across is not developed when using GPS.
Reading CF, it seems hard enough for them to cope with the inaccuracies of charts, (of course paper and echart)
Barry sv Risky Business

[Simi 60]

Originally Posted by transmitterdan

GPS is exactly the same in Northern and Southern Hemisphere. Coverage gets weaker at higher latitudes both north and south. Australia is covered about the same as the northern US.
.

and taking that on board, when I google the problem there are plenty saying GPS dropouts and poor plots are an issue in the northern hemisphere as well.
Very noticeable on images of car tracks on maps where GPS track doesn't match road.

long cables require the right electrical signal design. NMEA-0183 is designed to go >30M. 5 V single ended is designed to go about 1 meter

So why does every antenna manufacturer I looked at, even US and Japan, sell them standard with 10m cables?
Clearly its not just "China bad" as you imply.

[transmitterdan]

Originally Posted by Simi 60

So why does every antenna manufacturer I looked at, even US and Japan, sell them standard with 10m cables?

Clearly its not just "China bad" as you imply.

Because the “good” brands use the proper NMEA-0183 design which works perfectly up to 30M or more. The Seiwa antenna and cable is not NMEA-0183 compliant. It is using a single ended 5V interface copied from a hobby electronic kit designed for experiments using wire length up to about a meter max. It is not fit for a boat IMO. It costs 10X times the money (like $2.5 vs. $0.25) to manufacture a proper NMEA interface. The 5V hobbyist interface is much cheaper to build.

I see these shortcuts sometimes in Chinese equipment. Not all Chinese equipment is bad. Most is actually very good. The USB GPS pucks that sell for US$25 are really good. But most of them use USB and a short cable because that is really inexpensive these days.

[Pelagic]

Originally Posted by Dockhead

I don't understand why this discussion is so polarizing. The main issue is the SKILL. Not the choice of tools. The tools by themselves won't do the job. Electronic charting is a great boon but is not a magic bullet which suddenly means you don't need any skill. Nor is satellite imaging nor is a dumb paper chart. Even the "art of pilotage" as described by Ping -- that particular, powerful method which good sailors know -- may not be enough if you neglect to collect other data by other means when it's necessary, and use other tools, whatever they are, when they can increase your awareness and orientation.

Totally Agree!

Nice example and trick Dockhead.....we've all been caught out one time or another with missing or failed navaids and finding an alternate method to find your way into a safe haven is the real Art of Navigation!.

Humility plays a big part in that and my most poignant reminder was after a long and exhausting commercial delivery of a large tugboat from Acapulco to Vancouver with a " harbour oriented" and difficult tug crew that managed to get lost on the last night watch of open waters approaching English Bay / Vancouver in heavy rains.

Pre- GPS only Radar Navigation, they finally woke me up hours past our aproaches ETA lost in heavy rain and low cloud with mountainous radar returns and inlets.
They admitted to being lost, as I could find nothing that looked like the entrance to English Bay on the radar.

For 2 hours, I searched for a matching Radar return while trying to calculating which inlet or sound we must be near.

Finally I spotted 2 guys sports fishing off a rocky outcrop, swallowed my pride and asked them where we were?

Turns out my tug crew had overshot by miles and we were near a place called Halfmoon Bay......
It was a very quiet end to a long journey in that wheelhouse![emoji35]