Speed hut GPS speedometer jumping?

[Murd]

Curious if anyone else has experienced this, and if there is a fix.
My speed hut/FFR vintage gps speedometer occasionally will have its needle swinging up and down all over the place.
I’ve only noticed it at higher speeds at or around 120km/h and when heading directly north or south. North seems to be worse. Will do it for a while then get a small curve in the road and it will go away.

My GPS antenna is on top of the driver foot box, all the way forward, about 14” in front of the windshield so pretty far from having any metal above it to block the signal.

Anyone experienced this or have any ideas?

[BadAsp427]

I have similar problems... I've figured it to be just bad reception from the satellite... I have a few areas of dense trees that cause it... Also when I was up in the mountains, it happened... It usually only happens every now and then.... But it does/can make for some really cool story telling when someone asks how fast have you driven your car and you pull up your memory and it says... 142mph... that's what mine says currently...

[bobl]

You might try displaying the digital speed. If this remains steady and the needle floats it is a speedo problem. If it is changing similar to the needle then it is most likely satellite reception. The speedo converts the digital value to an analog movement for the needle. The needle movement does not react as quickly as the digital display.

[edwardb]

I've noticed mine bouncing around or even dropping to zero very briefly a few times in 5000+ miles. Maybe 4-5 times total. Once was on a heavily tree lined highway, so clearly signal related. I suspect that's the case for every time it has happened.

[Vspeeds]

I only have 800 miles and on the last drive I noticed the needle was stuck at 0 with no advancing mileage. I stopped and pressed the reset button and everything cycled through, the needle even moved to the highest memorized speed. I drove again and still nothing. I turned off the car and re-started it and the speedo worked fine. Everything seems fine now. I just have about 10 miles of unregistered mileage. I haven't seen the needle bounce around.

[Papa]

The further north you are, the more likely you are to experience satellite dropout. To calculate position and then speed, your receiver needs a lock on four satellites. The dropout you are experiencing is likely occurring when you loose one satelite and the receiver is acquiring a different one. For normal navigation, these dropouts aren't really noticed due to data being buffered and updated over several seconds. Obviously your speedo can't buffer data and must update a lot faster, so any disruption is noticed.

[Ducky2009]

Mine has stopped briefly a few times. "Jumping Around". The needle would drop towards zero' but never went above my current speed. Assumed it was a bad signal.

[Dewey McBride]

Twice in the last 5,000 miles I've had mine stuck at zero. It said acquiring signal for at least a whole day once, and it did it again on Sunday for about 10 miles. I figure it's something to do in the atmosphere. Funny that my phone GPS worked just fine.

[GFX2043mtu]

This is the reason I had Speed Hut convert mine right of to a standard VSS signal. I realize gps is easy, I just didn’t want the drop out issues. I think it was $100 if I recall. All you need to do is run the VSS signal wires from the transmission to the gauge and your done.

[Vspeeds]

Twice in the last 5,000 miles I've had mine stuck at zero. It said acquiring signal for at least a whole day once, and it did it again on Sunday for about 10 miles. I figure it's something to do in the atmosphere. Funny that my phone GPS worked just fine.

My speedo outage happened Sunday also. I looked on the web and learned there were solar radiation anomolies on Sunday that affected radio signals. Interesting.

[Murd]

Thanks for the replies everyone, just wanted to confirm this was a gps issue and not an issue with my setup or hardware. It’s rarely a problem for me and not too concerned.
Thanks

[Dewey McBride]

My speedo outage happened Sunday also. I looked on the web and learned there were solar radiation anomolies on Sunday that affected radio signals. Interesting.

Good to know that's the answer. It did it again all morning yesterday. In the afternoon the signal came back.