First, lets take a look at what I'm trying to accomplish. I want four monitors, one for each of the two NSO processors, and one for each of the two computers. And I want them as large as will fit. Furthermore, I want all the monitors to be identical so I can interchange what's displayed where in case I change my mind about the arrangement of displayed information, and for backup/redundancy in case of failures. All this rolls up to four 19" non-wide screen monitors. Sounds simple, right? If only it were....
The next major decision is whether to use "marine" monitors or standard commercial monitors. The marine monitors have a few features that tailor them to the application, some of which I care about and some I don't. The features and their relevance to me are:
- Waterproof. These four monitors are going in the pilot house, so there is no need for waterproof monitors. I don't care at all about this.
- DC-powered. This has some attraction since it theoretically reduced power consumption by eliminating the inverter losses to run off AC. Underway the engine generates plenty of power so this only matters when running the displays at anchor. DC power brings a slight advantage, but it's not a deal breaker.
- Designed for panel mounting. The marine monitors are designed to be panel mounted and come with all the necessary hardware. This is a slight advantage, but the boat yard is quite good at mounting standard monitors so this doesn't really matter.
- Lots of different inputs. Each monitor will be connected to exactly one device via DVI, so I don't care about this feature at all.
- Dim-to-black control knob. This offers convenience when dimming the monitors for night operation, and dimming all the way to black is handy. But a button menu to dim is OK too if it's simple, and theatrical gels can be used over the screens to dim them more if needed. So the dimmer knob is a slight convenience, but not a deal breaker.
Backtracking a little, the NSO bundle that I bought included a 17" marine monitor, and using it I came across an interesting issue. I'll apologize in advance for the deeper than usual tech dive.
All monitors contain a certain number of pixels arranged in a grid. The computer lights each one up to draw whatever image is required. Pixels are square so the computer knows how to properly draw circles, squares, etc. Monitors all have a "native resolution" which is simply the number of pixels horizontally and vertically on the screen. Normally the computer matches it's output to the monitors dimensions giving the clearest images. But monitors can also handle smaller input dimensions and upscale the image to fit the screen. You with me so far? We are almost there.
When scaling an image, you need to consider it's aspect ratio. An image that has 4:3 aspect ratio has 4 horizontal pixels for every 3 vertical pixels. 4:3 is the ratio for old-style TV. 16:9 is the ratio for wide screen TV. All this matters because when you scale a graphics image. You need to maintain the aspect ratio. If you don't, the image distorts. Squares are no longer square, and circles are no longer round. On your TV you have probably seen "banding" at one time or another. Those are black bands either above and below, or on either side of the image. This happens when you scale an image to fit a screen that is a different aspect ration than the image itself. You have probably also experienced the fat-ass syndrome where people on screen, especially towards the outer edges of the screen, seem to have particularly wide stances. This happens when you do not preserve the original image's aspect ratio and instead stretch it to fill the screen and it's aspect ratio. You can sort of get away with this for video, but it's a big no-no for graphics where squares need to be square and circles need to be round.
OK, with that tutorial out of the way, let's go back to the 17" marine monitor that came with the NSO. The monitor has a resolution of 1280x1024 which is 5:4 aspect ratio. It turns out, but the way, that 100% of the 17" and 19" non-widescreen monitors on the market are 1280x1024, 5:4 ratio. The rub here is that the NSO outputs 1024x768 which is 4:3 ratio. No problem, right? The monitor should scale the input signal of 1024x768 to fit the monitors 1280x1024 pixel grid. Maintaining aspect ratio, the image would scale to 1280x960, leaving a top and bottom black band on the screen.
Well, not with this monitor. Instead it stretches the image to fit the full 1280x1024 screen thereby converting the aspect ratio from 4:3 to 5:4 and turning all the circles into ovals. WTF? Instead of range rings you have range ovals. WTF? After a little back and forth with the manufacturer I concluded there was a reason why this "marine" monitor only cost $2000 where the others cost $4000. And it turns out this was just the tip of the ice berg.
Having rejected expensive marine monitors because of their ridiculous cost, off I went to research commercial monitors. I had a number of leads based on monitors used on other boats and web research. I also had a clear preference for LED monitors. LED back lighting, as opposed to florescent back lighting, tends to be brighter and lower power. The first challenge was finding a non-wide screen monitor. Nearly all monitors are now wide screen. It appears that the convergence of computers and video has indeed taken place. But most major vendors still have a 19" non-widescreen monitor. My first two pics were an LG and a Viewsonic. I bought both, figuring that I'd just return whichever one lost the comparison.
Long story short, both monitors, along with the original "marine"monitor and two more subsequently purchased ALL distort the NSO video signal when scaling it to display on the monitor. Now a little more attuned to the issue, I rejected two or three additional manufacturers based on their manuals and/or tech support feedback. That's seven manufacturers all of whom incorrectly scale input images. At this point, I give up, and conclude that all the current LED monitors of this class improperly scale images. So what's next?
A fellow Nordhavn owner much more skilled in google searching that me discovered a device by a company called Gefen that scales VGA input signals to match various DVI output signals. It looked promising, so I bought one. The good news is that it does indeed scale the input signal while maintaining aspect ratio. But the bad news is that the video quality is poor. Edge definition is fuzzy and the overall appearance lacks sharpness.
It seems I can live with one of two issues; distorted graphics shapes, or overall fuzzy images. hummm?
And what about those expensive "marine" monitors? Do they scale images properly? Reading their manuals, it would appear some have an option to "maintain aspect ratio" so I think the answer is yes, but is it worth 30x the cost? For me, the answer is No. I just can't bring myself to pay such a "yacht" price for something, and I have a problem in principal rewarding any company with a purchase who has such business practices. There are plenty of yachties with deep, wide open wallets, but I choose not to be one of them. I'm happy to pay for value, but come on, 30x is ridiculous.
Are you dizzy yet? Well, welcome to my world. It seems ridiculous that this is so complicated, but it is. That said, in fairness I have to admit that a big part of this is due to the Simrad NSO which is only able to output 1024x768 which does not match current monitor technology. Furuno, and perhaps others, output 1280x1024 which happens to match the monitors and hence does not exhibit this problem.
The bottom line is that I have 3 choices:
- Live with the distorted graphics from commercial monitors
- Use the Gefen scaler to preserve aspect ratio, but at the expense of somewhat fuzzy graphics.
- Spend a King's Ransom on a marine monitor which may or may not work.
The final choice is a Samsung S19C450BR. Partly because it's one of the monitors that I haven't returned yet, but more because it dims closer to zero than the others. It also looks like it will be easier to mount than others, and at 16W it's pretty energy efficient.
Link to next article on monitors