Does the 701 calculate Density Altitude?
Thanks
Thanks
- Thread starter fmjfirearms
- Start date
I believe it does (or more accurately, AB does) based on temp, humidity and barometric pressure.
No, the Garmin uses Pressure and Temperature.
Pretty sure you add in humidity manually....
So if I manualy put in humidity, it will work out DA?
The device does not use DA. Neither does it output DA. It will take into account the Humidity if you input one (if you don't shoot ELR then I suggest just leaving it at 50%).
Hi Doc
If it doesn't use DA, does that mean DA is not that important for AB to calculate drops?
If it doesn't use DA, does that mean DA is not that important for AB to calculate drops?
Pressure temp and humidity is DA. It just doesn’t tell you what the DA is. If you want a quick formula to guesstimate what your DA is use this: every 15 degrees Fahrenheit above or below standard is a 1000’ increase/decrease in DA. So for example it’s 74 degrees at sea level, that’s a 1000 ft DA (NOTE that this does not consider pressure changes when calculating DA but it gets you close enough)
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Okay, now I get it, I read the manual and did not quite get it.
So AB on the 701 is using DA, but you just cant see it.
No problems.
Thanks
Mark
So AB on the 701 is using DA, but you just cant see it.
No problems.
Thanks
Mark
Exactly what I was driving at....
No, AB does not use DA to perform calculations. It uses temp, pressure, humidity, etc. DA is less accurate than actual measurements.
Hi Doc
Thanks, I appreciate the feedback.
I think I have finally got my head around it.
My initial thoughts on the 701 after playing with it for a few days is it's a good unit.
It will be interesting to see how close it gets with my Sig 2400.
My only criticism would be the manual is not detailed enough (just Like the Sig 2400)
It's written by the software guys who know it backwards, not in mind for new end users.
If it was not for forums like this a lot of people would get very frustrated with these new devices.
Thanks, I appreciate the feedback.
I think I have finally got my head around it.
My initial thoughts on the 701 after playing with it for a few days is it's a good unit.
It will be interesting to see how close it gets with my Sig 2400.
My only criticism would be the manual is not detailed enough (just Like the Sig 2400)
It's written by the software guys who know it backwards, not in mind for new end users.
If it was not for forums like this a lot of people would get very frustrated with these new devices.
Resurrection this thread not because of DA but the fact that the 701 station pressure is off by 0.11inhg compared to two kestrels meters. The kestrel metes are within 0.02inhg of each other.
SP being off that much with the 701 is going to cause some vertical issues at distance.
SP being off that much with the 701 is going to cause some vertical issues at distance.
It's really not. Mess with the numbers. Your drop won't be affected unless there is a change in da of a bare minimum of 500 ft, reality more like 1k. Temp is the biggest factor, but that's because it changes velocity as well as your DA. it takes 15 degrees to change da by 1000 ft, what do you think 15 degrees does to your velocity? So is it not accounting for increased velocity or a change in da that caused your miss?
I run a 701 and was wondering the same thing, and then this thread pops up. Good to know.
I left Humidity at 50% and use a temple sensor for temp. With the CDM for my round I've had good luck making first round hits at 1k + with my 6.5 CM.
@DocUSMCRetired does the Kestrel 5700 elite w/ AB do this calculation differently using DA? Or is the math done the same way?
I left Humidity at 50% and use a temple sensor for temp. With the CDM for my round I've had good luck making first round hits at 1k + with my 6.5 CM.
@DocUSMCRetired does the Kestrel 5700 elite w/ AB do this calculation differently using DA? Or is the math done the same way?
Humidity has the least effect on DA. I set mine at 50 and leave it as well. The variation between a kestrel and Garmin isn’t a formula, it’s the sensitivity of the barometer measuring pressure.
I normally do all my simulations out to 4K yards cause that’s what the 701 is going to be used for.
I guess I looked at the numbers and thought it was more dramatic. Either way 0.11inhg error contributes to 50” of vert uncertainty where as a 0.02inhg contributes to a about 28” of vert uncertainty.
4K yards?
yes. ELR shooters train beyond 4K yards up to 6 to 7k yards. Let me say it again, train.
ive got to say that if a 90 ft elevation change cases your drop to double something else is afoul. Besides, that deep into subsonic who knows what’s actually going on. In addition, AB won Ko2m using a foretrex before it ever went public so I’m just guessing there is no isssue.
who cares? It’s an accountable uncertainty and I pointed it out. The pressure sensor is off. Stop trying to turn it into something else.
Maybe the kestrel is the one that is off? It’s a man made device that has an error factor to it. The tolerances aren’t zero on either device.
Been using my 701 for awhile now, all over the US. It has always worked for me...
