# Laptop GPS?

Discussion in 'Instruments / Avionics / Electrical System' started by Greg Mueller, Oct 10, 2007.

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1. Oct 10, 2007

### Greg Mueller

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I have a laptop which has slots for PCMCIA cards. I was looking around on the net and found GPS PCMCIA cards, some with remote antenna inputs. I'm thinking that you could mount a remote antenna on top of the plane and then just plug in your laptop and blast off.

Is there any reason this wouldn't work for aviation?

2. Oct 10, 2007

### Topaz

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None in particular that I'm aware of - I use a GPS with a remote antenna in my truck all the time. You'd want to do some careful checks to make sure that nothing in the environment of your airplane was degrading the signal for the GPS. Most 'commercial' GPS units aren't intended for the aviation environment.

I think the reasons it's not done are more in the practical vein. I don't know about yours, but my laptop's batteries only last about 2-3h with the display on full-time, so you'd need to wire up a power supply in the aircraft that could take the load of the laptop, with clean enough power for the laptop's needs. Then you'd want to make sure the laptop is securely mounted in the cockpit, someplace in convenient view but not obstructing the outside, and in such a way that it's fairly well isolated from the vibration of the aircraft. Even modern laptops don't like lots of vibration over long periods. Also, the displays generally are too bright for nighttime use - you'll wreck your night vision unless the laptop and the software can dim way down.

Lastly there's the issue of reliability. Unless it's being used as a backup nav, it'd be a really sucky night when you're trying to figure out where you are and suddenly you get the Blue Screen of Death.

I've seen some neat nav applications for sailplanes that use GPS and a palmtop, but they don't face the nighttime vision issue, and sailplane pilots generally fly by ground reference much of the time, anyway, and the GPS is more of a backup and recording device for the flight trace.

3. Oct 10, 2007

### etterre

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Depends on what you mean by "work..." There is a company (or two) out there that has essentially done that with tablet pcs and sells the package deal. www.mountainscope.com is one of them.

For what it's worth, I'm a software developer and I'd much rather buy a used Garmin 196 or 296 than mess with adding a card (bought at Best-Buy or Circutit City) and software to a laptop/tablet pc. I'm also the sort that flies with the sectional on my knee and my finger on the piece of the map nearest my real location.

Why?
1. fewer cables
2. better battery life
3. easier to mount in the cockpit
4. refresh rates on the Garmin x96 will probably be better
5. Aww @!#%!, the software that comes with the card is geared towards cars so it doesn't show altitude.
6. Double @!#%!, the software that comes with the card is geared towards cars so it doesn't show any aviation data (nav-aids, airports, terrain, etc.)
7. Triple @!#%!, the software that comes with the card is geared towards cars so it gets confused by motions faster than 150 mph.

As a developer, I can also probably fix 4 - 6 on my own as long as I can get the specs for the card - but that sounds like a lot more work than is justified by the $800 brand-new-in-the-box price of a Garmin 196. 4-6 are also probably fixed by the MountainScope software...but I'd want to see a demo first (Aircraft Spruce lists it on their website as about$500 worth of s/w :speechles) So that would be $500+the GPS card+fiddling time... 4. Oct 10, 2007 ### orion ### orion #### Well-Known Member Joined: Mar 3, 2003 Messages: 5,800 Likes Received: 135 Location: Western Washington Personally, I'm looking at this one http://www.vfrcopilot.com/1_esectionalsUSA.htm Look at their hardware options. Right now I fly with an AvMap EKP-IV but I'd like something with more aviation related data, The EKP-IV is OK, especially now with the latest database update, but the VFR Copilot uses the actual charts, combined with the GPS. Looks pretty good. Last edited: Oct 10, 2007 5. Oct 11, 2007 ### Midniteoyl ### Midniteoyl #### Well-Known Member Joined: Sep 4, 2003 Messages: 2,406 Likes Received: 500 Location: Indiana Lotta GPS's use WindowsCE so I would'nt think that would be a problem... 6. Oct 11, 2007 ### etterre ### etterre #### Well-Known Member Joined: Aug 30, 2006 Messages: 313 Likes Received: 1 Location: St. Louis, MO, USA It wasn't the OS (WinCE/XP/Tablet) that I was thinking of having to install/configure. There has to be some "moving map" software that knows how to talk to the card, look up the reported position in some sort of file, and then display everything on the screen - and while it's probably "free" with the card, it's probably also not aviation-friendly. <shrug> Another possible problem that occurred to me after the fact was the hard-drive in the laptop itself. Since the read/write heads float over the disc on a cushion of air, after you reach a certain pressure altitude the hard drive will crash. The newer/better/faster/smaller hard drives are a little more prone to this because the tolerances are tighter, but the older/slower ones are still affected. Unfortunately, the required pressure altitude is not the sort of thing that the hard drive manufacturer is likely to list in the specs... The first I ever heard of this sort of problem was from a guy who used his iPod for inflight music and it kept "dying" whenever he went over 5,000 feet. Edit: I'm an idiot. The iPod actually has a warning in the manual about not using it an altitude of more than 10,000 feet. Sorry about that - I should have looked it up before posting Anywho - while I'm sure it could be made to work (and I'd be curious to hear from Greg if he does try it), it seems to me that it's a classic buy or build scenario. Do you spend the time and energy overcoming the issues to save a couple of$\$ and have exactly what you want -or- do you save up your nickels and settle for what you can buy and use right now?

Last edited: Oct 12, 2007
7. Oct 12, 2007

### Topaz

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Well, modern laptops are generally expected to operate at the cabin pressure altitude of a typical airliner, and if I'm not mistaken, that's approximately 8,000 ft.

8. Oct 15, 2007

### etterre

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9. Oct 17, 2007

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