Garmin/GoPro interference - NOT!
 

MY BAD! After accidentally leaving the camera off and finding the Garmin still was dropping out, I discovered that the wheel magnet for my speed/cadence sensor was to blame. Why it worked for 3 months and then started to drop out the same day I put the GoPro on, who knows, but no doubt it is a magnet issue. Sorry for blaming GoPro :(

I recently rode 500+ miles with both GoPro and garmin etrex side by side --with no problems at all. This is probably not helpful to you, though --since neither my GoPro (older version) nor my garmin support wifi. Presumably your issue is with their wifi signals. Can the wifi be disabled on either or both units?

The Edge 800 doesn't have Wifi and Wifi was turned off on the GoPro. I put a layer of aluminum foil between the 800 and its silicone case. No help at all. Next test is to change video recording mode from 1080-60fps. to 1080-30fps and see if it changes anything. Argh...

Not that's it's necessarily pertinent to your situation but are you using a wheel sensor with the Garmin?

My thoughts too. If you are using GPS to dictate speed and a wheel sensor they compete and the garmin basically looses. Go to strickly GPS for speed and see of that problem is solved.
Velocity

I do have a wheel magnet. I don't see how removing it would have an effect, but I'll try it and let you know!

Apparently RFI from the GoPro is common with RC airplane folks, too https://www.google.com/search?q=gopr...a&channel=fflb. I've ordered some copper foil to try if removing the magnet doesn't fix it.

A bit OT, but what thoughts are you inferring I had based on my only having asked whether he was using a wheel sensor?

Where did you research this?

I've never had a problem with my 705 inches away from the GoPro, and I've even put my GoPro into R/C planes and flown them around, with both 72 MHz and 2.4 GHz gear, with no problems. (To be fair, GPS uses 1228 and 1575 MHz, so this certainly is an apples to oranges sort of comparison.)

Which GoPro do you have? I've used the GoPro HD and GoPro 2 with no problems, haven't tried the 3.

One thing that might be more informative would be to look at the satellite display where it gives the satellites used and signal strengths -- I assume the 800 still has that -- and see if turning the GoPro on and off has an effect. You can do that without even going on a ride. (Of course, I'm assuming that the problem is with the GPS signal reception and not something else.)

If you can reproduce the problem like that, try somebody else's GoPro, see if it's just yours. Or try somebody else's Edge. If you have the GoPro 3, do make sure the WiFi is off, though of course the frequencies are different enough that it should not cause a problem.

I asked about the problem on the Garmin forums https://forums.garmin.com/showthread...use-gone-flaky and one of the mods told me it was not uncommon. Did a Google search https://www.google.com/search?q=gopr...a&channel=fflb and found lots of cases of them interfering with all manner of devices, mostly RC airplanes.

I have the Hero 3 Black Edition. WiFi is always off.

The GPS signal screen shows many satellites being received with various signal strength, but enough of them that being able to properly track shouldn't be an issue.

One thing interesting is that when watching my GPS speed, it drops to exactly half for a second or two and then pops back to accurate speed. One time, and only once, I saw it drop to 0, but it drops to half speed every 15 to 30 seconds and then pops right back. It's enough though that my GPS mileage is off by a mile or more at the end of an hour and a half ride. And GPS average speed, etc. is equally affected.

I got my copper foil in yesterday to shield the GoPro. It's such a common problem they even have a template for cutting your foil :) https://app.box.com/s/s4296unsmn1as8i78up2

I assume you have removed the GoPro completely and ridden the same path as when the problem occurred -just to verify this isn't simply a garmin-800 problem. Are you riding under power lines? In heavy tree cover? Under heavy cloud cover? Near airports?

Interesting! I use my GoPro3 Black and Garmin 510 right next to each other every day with no problem.

The identical symptoms occur when your battery is low in your cadence sensor.

I solved it by replacing my battery and removing my wheel magnet.

My Edge 305 rarely goes into autopause. A week ago it did it about 10 times during a ride, even in open areas.

IOW, you might do some more rides and see if it was just chance.

Not the GoPro!

True a little presumptuous but I thought that you were referring to the clash that two differing sensors competing for the right to post their findings on the Garmin device. I digress
Velocity