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/ Breadcrumb GPS

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David Coley - on 11 Jan 2018

Building on thread https://www.ukclimbing.com/forums/gear/handheld_gps_-_advice-668032

I'm after a GPS that will allow me to follow my approach route back across mountain terrain in a white out. For example getting back to the Midi ridge.

I know nothing about GPS, but I assume I need : good battery life, easy to use as it won't get used much and I'm not sure I will remember things deeply buried in a menu system, visible in poor conditions, lightweight. I don't think I need maps but others might know better.

I have never used a GPS so no idea if a watch would be OK or unsuitable. 

Thanks for your help. 

guy127917 - on 11 Jan 2018
In reply to David Coley:

I use the Garmin Fenix 3 for this, works very well.

Toerag - on 11 Jan 2018
In reply to David Coley:

I don't think a watch would be suitable due to battery life issues but stand to be corrected as I've not kept abreast of watch battery lives since they first came out and would only last a couple of hours.

I think what you require is a GPS that has a 'follow track' feature.

1
pdone on 11 Jan 2018
In reply to David Coley:

The Garmin Etrex 10 will do what you want.  The last time I looked Cotswold were selling it at £80.

Stefan Jacobsen - on 11 Jan 2018
In reply to David Coley:

Gaia GPS will do just that. I use it very frequently.

GrahamD - on 12 Jan 2018
In reply to David Coley:

I believe my Garmin 310 XT watch has that feature, although its a bit long in the tooth now !

krikoman - on 12 Jan 2018
In reply to David Coley:

Since GPS requires clear skies to receive satellite data, you might struggle to obtain a signal in white out conditions.

So I wouldn't recommend any GPS for this, that said they may be useful at night time.

5
pdone on 12 Jan 2018
In reply to krikoman:

> Since GPS requires clear skies to receive satellite data, you might struggle to obtain a signal in white out conditions.
> So I wouldn't recommend any GPS for this, that said they may be useful at night time.


Clouds do not 'stop' satellite data reaching your GPS receiver. 

If this were true I doubt many would buy one. 

 

krikoman - on 12 Jan 2018
In reply to pdone:

> > Since GPS requires clear skies to receive satellite data, you might struggle to obtain a signal in white out conditions.
> Clouds do not 'stop' satellite data reaching your GPS receiver. 
> If this were true I doubt many would buy one. 
>  


Clouds don't you're right, heavy snow can and does though. Heavy rain can do the same.

1
SebCa - on 12 Jan 2018
In reply to Toerag:

I have a Garmin Fenix 3 HR, Etrex 10 and Oregon 650 which will all do this feature and the best battery performance with out doubt comes from the watch!

SebCa - on 12 Jan 2018
In reply to David Coley:

Another vote for the Garmin Fenix, as above I have the 3HR they have been updated to the 5 recently but the 3 is more than capable and will be at a knock down price!

David Coley - on 12 Jan 2018
In reply to krikoman:

Ek!

I did not know this. W.r.t snow how serious an issue is this?

 

krikoman - on 12 Jan 2018
In reply to David Coley:

I think they've improved things, with dual receivers, but I still think it can be an issue.

richlan - on 12 Jan 2018
In reply to krikoman:

I don't think this is true, have you any evidence to support a GPS signal being degraded to such an extent that it wouldn't work in bad weather?

Rigid Raider - on 12 Jan 2018
In reply to David Coley:

Surely a big ball of string would remove all doubt?

captain paranoia - on 12 Jan 2018
In reply to Rigid Raider:

Or breadcrumbs...

captain paranoia - on 12 Jan 2018
In reply to krikoman:

> Clouds don't you're right, heavy snow can and does though. Heavy rain can do the same.

Tropospheric conditions can have an effect on GPS signal reception, due to both attenuation and scattering. Look up Hopfield Tropospheric Model if you're interested...

But a modern, high-sensitivity receiver should not have too much trouble coping with that.

Tree cover also can cause partial blocking and attenuation of the signal; can be more significant than rain and snow, depending on the canopy density. Scattering is not as significant, because the depth of the tree canopy is insignificant compared with the line-of-sight path length.

Probably the most significant issue with ground-based GPS reception in mountain environments is the canyon effect; complete blocking of visibility of parts of the sky, plus reflection of signals off large faces. This can result in position errors in the order of hundreds of metres.

krikoman - on 12 Jan 2018
In reply to richlan:

> I don't think this is true, have you any evidence to support a GPS signal being degraded to such an extent that it wouldn't work in bad weather?

Only my own, but with two different units, once while skiing in a particularly heavy snow fall, the other while riding my bike in a down-pour.

https://www.gps.gov/systems/gps/performance/accuracy/

State; atmospheric conditions, but nothing specific specific.

It could be that both these instances I witness coincided with other thing e.g. solar flares etc, but they were both in open country and the skiing one had been OK before and was OK after, the snow, on the same run.

Post edited at 14:20
krikoman - on 12 Jan 2018
In reply to captain paranoia:

Nice one.

wivanov - on 12 Jan 2018
In reply to David Coley:

Over the years I've owned these: Magellen Meridian, Garmin Etrex Vista, Garmin 60Cxs and a Garmin Forerunner 410 GPS watch.

The Forerunner does not have enough battery life for any extended trips. Ten hours or less battery charge. Any "mapping" GPS will do breadcrumbs. I prefer ones with replaceable AA batteries as opposed to rechargable only.

I've used my GPS for hiking, climbing, geocaching thoughout the States, Caribbean, and Central America. We've hiked up inactive volcanoes and out to Mayan ruins. They've worked well in extreme winter conditions in New Hampshire and Maine.  Never had a problem with signal due to weather (except in a rain forest -  with a wet leaf canopy). I've been told that the frequency specifically chosen for GPS was so that it would work in most weather conditions. That has been my personal experience.

Also, check to see if whatever GPS you chose is capable of using open source maps (like Open Street Maps) instead of the expensive subscription maps the manufacturer sells

Post edited at 19:48
wivanov - on 12 Jan 2018
In reply to David Coley:

Also, something you can do with a handheld mapping GPS that I don't think you can do with a GPS watch is "project a waypoint".

To explain: one winter night we were snowshoeing sometime after midnight up along the Fenton River in Connecticut. Minus 8C, windy with swirling powdery snow coming down we were following a glint trail through a state forest.  The glints ended at a icy, deep gorge with high, fast water flowing. The gorge was about 20 meters across and deep enough to be scary. We could see more glints off in the distance on the other side. But, we only had snowshoes and Micro-spikes, not proper crampons. There was no way I was going to cross down because one slip and we'd be swept away. But, I could see on the GPS that there was a foot bridge about 0.5 km upstream.

So, I used the GPS to waypoint (mark) where we were and then used the GPS to take a compass bearing and estimate a distance on the other side to where I thought the next glint was.  With the bearing and distance, I marked (projected) another waypoint on the other side.  We hiked upstream, found the foot bridge, crossed and set a course to bushwhack to my projected waypoint. Once there, we picked up the glint trail and continued on. All in all a nice adventure.

kevin stephens - on 13 Jan 2018
In reply to David Coley:

Suunto Traverse, check out the specs and reviews; great altimeter functions too which can also be useful in a whiteout

David Coley - on 13 Jan 2018

Thanks everyone for your help. 

 


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