GPS speedometer fluctuations

[docc]

I realize there are only a handful of us running GPS speedometers, but I hope someone can help me understand an odd phenomenon that has happened twice on my GPS Speedhut.

 

A few months back I was on the interstate about five miles form home and I noticed the speedometer needle hunting. I knew I was rolling about 80mph, and needle was moving erratically from about 60 to about 90. Haven't seen it do that before, or since.

 

Until today. It struck me that I was on that same stretch of road moving at about the same speed and the GPS speedo became erratic. I toggled to the digital speed display and saw it was fluctuating continually, sometimes displaying "0.0."   This happens to be in a very gentle approach and departure to a river bridge. Not mountainous or shielded from the sky in any way.

 

First occurrance, I thought it was something with the Speedhut, like a recalibration function or something. This time, I got thinking V11 electrical (read: docc's sketchy wiring).  But it was in the same area and I appeared to have "ridden out of it."

 

So, what gives? GPS hole? Is that even a thing?

[footgoose]

I'm sure there are "holes" for consistant gps connection. I's happened to me a few times on my I phone maps/directions gps. Oddly enough, two times were in TN. Once when I went to pick up the Rosso, the blue dot went down the road without me, and would Not recognize my turn. Another time the blue dot went off on it's own through an open field, then came to it's senses a half mile down the road. Did the same thing on the way back. Weird. East TN.

Seems legit it would mess with the speedo too

[bbolesaz]

Too close to Oak Ridge ?

[Tomchri]

Black Holes,, hm, had a question the other day about timing sensor behavior.  Starts fine and full throttle ok,,,, but dies at 2200 ? New sensor in, all ok.

Sorry doc no advice, just another electro   Wonder.  

Did like the comment about Guzzi educating electricians since 21 

Cheers tom.

[Rox Lemans]

GPS speedos are good. They have their shortcomings but theyre good. When I rode Scud's I remember some small things on it. They are accurate (at least way more accurate than OEM). However there is a delay. In stop and go traffic theyre worthless. They need a second or 2 to kick in. But they do work. I have a set put aside for when one of my bike's speedo or tach takes a doo doo.