as above. preferably with a stem mount rather than a bar mount.

the gekos dont seem to which is a shame.

cheers.

Does it have to be a GPS? GPS data isn't that accurate for altitude, the top end Garmin Edge for instance uses pressure for altitude readings. So on that basis some of the normal bike computers that have an altitude reading may be better and cheaper for what you want.

doesnt have to be gps - was lead to believe from reading about that they are more accurate than devices which rely on barometric pressure, thats all.

friend has an etrex vista which seems to give good altitude readings. he doesnt always come out tho and i like to guage my ride bu height climbed rather than miles - makes me feel better :-)

you can buy watches that will include an altimitor

No way is GPS more accurate than a barometer. Why do you thing aircraft use barometers

Aircrafts use Barometer because it's cheaper and GPS has only been around for 10years, I don't think GPS is FAA approved also, so only allowed as a backup system.

My old watch had altimeter, don't think it'd keep track of height climbed though sadly.

Height climbed is definately more relevant than miles ridden IMHO.

I use the Edge 205 with GPS altimeter and its great to look at the graph on the pc after the ride. You can see gradient/elevation so you can see those real steep buggers.

Whilst it is on the costly side (£196 from Wiggle) the Garmin Edge 305 has a barometric altimeter which seems reasonably accurate.

The software (Training Center) which comes with it is pretty good.....as Adam said, it's really satisfying to look at some of the steep climbs afterwards (just don't plot heart rate at the same time !!).

It also comes with a couple of stem mounts.

Aircraft use 2 methods of measuring height. Bar Alt (Barometric Altitude) and Rad Alt (Radio Altitude). Barometric altitude needs data to be set up correctly. QFE (Field Elevation Atmosphere Pressure) and QNH (Sea Level Atmosphere Pressure). Both of these are imortant coz if you get this wrong you could fly into the groung as your instruments would have the wrong baseline. QFE is also entered into your flight management computer. Rad Alt uses a doppler radar to look at the ground. This is used as the prime altitude source below 500 feet.

Civil aircraft also use a system called EGPWS (Enhanced Global Positioning Warning System). This has a digital terrain elevation database within it that can be accurate to 1 meter. It uses the database and GPS and aircraft data (altitude/rate of climb/heading/speed/attitude/position) to tell the crew if they are about to fly into an obsticle (hill/mountain/whatever). I think that this is the same data that the hand held GPS company's use to derive their elevation gained information. It would definately be acurate enough.

Traditional pitot/static flight instruments (air speed indicator, rate of climb and barometric altitude) are still used because they don't need power or computers to make them work. Just a couple of air holes in the aircraft. They still work when your computer goes phut! They may be mechanical but they are not cheap. On newer jets they are generally standby instruments.

Does anyone know where I ca find accurate barometric details?

I've a Garmin eTrex Vista C and to callibrate the Altimeter I need to enter the correct elevation AND correct pressure. Where can I find these values?

The Met Office have some local info on their site. Have a look around.

Jon Doh! old low tech works on gliders as no power is available other than the radio if you've got one, but you just Zero the Runway as your not generally up long enough to need to compensate for pressure changes and it's more visual anyway.

Arry, you need a Map, enter the height your at on the map, but on variable weather days, 1hour later if U hit another Trig point then it's best to re calibrate and keep doing so.

I use a alitude watch for mountaineering ( Pre GPS ) works well on low visibility days, extra navigation aid.

Civil aircraft still have to have a old method, which estimates your position isn't that accurate over the sea anyway and costs something like 200K to install into a 747, uggg. ( 2 mile accuracy typically )

Dylan. Ask Goaty if his Chinooks have Pitot/Static instruments. I know they do coz I worked in the UK's only Chinook sim training centre for 3 years. The bloody Merlin even has them squeezed in amongst it's "glass cocpit". All of the sims where I work now have simulated Pitot/Static instruments in them. The sims are qualified to JAR level 1/CAA level D requirements and have to requalify every year. The instruments are there because they are in the real aircraft. They are in the real aircraft because they work.

You would also dial in the QFE from the tower or local met. That way you can tell is your instruments are goosed before you take off.

EGPWS cost varies. We the have real aircraft systems in the sims. We then feed them the information that they would normally get from the A/C. It's cheaper than trying to simulate the EGPWS system. And even at 200k it's still only a fraction of the cost of a new jet. It was always designed as a retrofit item so that you could upgrade any aircraft.

2 mile accuracy is complete bollox as well. With the jets doing in excess of 300kts a system with 2 mile accuracy would be laughable. It's meters.

2Miles, flying over the atlantic, they'll re position themselves better once they get some signals.

Worth while having old style stuff incase of power failure, used to like my instruments back when i used to glide.

Rate of Climb being of great use to find and stay in thermals.


Love to fly real planes, just not a millionaire :( and the 1000's of hours of training puts me off to :(

I heard a airplane came into a landing in Brum airport, approaching at 600ft not 6000ft with good visibility, the air traffic control spotted the error strangely not the pilot.

Bike computer with barometric altimeter, or GPS and mapping software like Tracklogs or Memory Map, but then you'll have to wait until you get home to see how much you've climbed ;-)

Plotting the Chart, Speed / HR / Height would make for a good training tool.


( I'd use it twice then relegate it to toys seldom used though )

Jon, don't waste your time :-)