Newton dropping DFPM signal

[entwistlejon]

Hello,

I've been recently riding with the Newton paired with Rotor Power DFPM and I can't even complete a calibration ride as the Newton keeps dropping the DFPM signal. Believe me I've made over 20 attempts and at some point along the calibration the Newton will read "DFP Fail" and then reconnect (which then screws up the calibration ride file rendering it useless).

As you'd expect, both Newton and Rotor (batteries) are fully charged. I've even switched off or removed all radio emitting devices (HR, cadence sensor, iPhone) but it makes no difference.

I believe it's the Newton as I've (perhaps hilariously) managed to ride with an iPad stuffed down my top with an ANT+ dongle with no issues in picking up and recording a constant and continuous DFPM signal.

Any tips (I'm desperate to try out the CdA functionality - which is the main reason why I bought the Newton in the first place)?

Thank you in advance.

[Velocomp]

If your Newton is receiving its ANT+ speed/cadence signals without problems, then the Newton is working properly.

ANT+ sensors and antennas are tricky (the Rotor is an ANT+ sensor) and it takes a lot of work to get them to work reliably on bikes. We have no idea how well the Rotor unit works, or how strongly it broadcasts its ANT+ signal.

Is your iPad mounted on your handlebars, immediately next to the Newton? If it isn't, then its operation is not a meaningful indicator of how well the Rotor sensor is functioning.

[entwistlejon]

Newton receives speed, HR signals with no issues whatsoever.

Last night I decided to do a road ride with the Newton next to a Garmin Virb Elite camera.

The Newton worked fine, until it decided to fail 10km into the ride. The Newton was still showing speed, HR and power data (but curiously not cadence) for the remaining 35km, but after uploading the data into Isaac no power or cadence data available in Isaac after 10km (the failure point). HR and speed are displayed in Isaac for the entire ride.

No issues with the Garmin Virb Elite (you can see the data here...http://tpks.ws/gxsL).

Both units mounted on the handlebar.

[Velocomp]

Your cadence sensor was knocked out of position. In the Newton, when cadence = zero, power = zero.

Use the Tools/Repair ride for missing cadence.. and your power signal will reappear.

Reposition your cadence sensor and all will be well.

[entwistlejon]

Thank you for your suggestion. I tried it but to no avail.

The likely reason being, the cadence signal is coming from the power meter (Rotor Power) itself. I've uploaded my ride file to demonstrate the problem.

I do have a standalone cadence sensor (Garmin), but thought it could potentially complicate matters if I installed it on the crank arm.

FYI, my speed sensor is also an independent unit (Garmin).

[Velocomp]

Hmm...it looks like the Rotor is misbehaving.

You'll note that, around mile 12.2, you are climbing a hill, but power and cadence are both zero, on both units. The Newton forces power to zero whenever cadence is zero. Since the Newton is reading the Rotor cadence, if it isn't sending cadence then this makes sense. But notice that the Rotor is also reading zero power...suggesting that it isn't working properly. Same problem happens at 2.8, 15.3, and then the long hill starting at 16.25.

In fact, you're getting short cadence dropouts on ALL of your uphills. That is where there is more stress and flex on the crank and arm. We don't have any experience with the Rotor device, but something odd is happening with it.

Installing a standalone cadence sensor would solve the Newton power issue, but not help with the Rotor.

[entwistlejon]

John,

On this evidence I totally agree with you that the Rotor is misbehaving.

However, yesterday I went for another ride where the Newton was constantly dropping and picking up the DFPM. For some periods of time it would display a stable signal, but on the whole, not much joy (see attached ride file).

I was also recording the same ride using my Garmin Virb Elite camera.

http://tpks.ws/NMhu

As you can see from the ride file with the Garmin, the power is continuous (no dropping of power signal/data).

Any thoughts on how to proceed? Is there a Rotor Power/Newton conflict?

[Velocomp]

I agree the Rotor signal is disappearing mysteriously. But we have never seen this issue on any other DFPM, from any other manufacturer, that has been paired to the Newton.

There are still lots of cadence dropouts, clearly a Rotor problem. Also, Rotor power reception is erratic; see screen shot below.

Power meters are tough things to make, in part because of ANT+ communication. There are ANT+ standards that manufacturers have to meet; I have no idea where Rotor stands. But Rotor is a new guy on the block, and it looks to me that they don't broadcast a particularly strong signal.

It may be that the Virb has a particularly good reception antenna, allowing it to more consistently read the Rotor signal. But I can't tell from the TrainingPeaks data how solid the Virb data is, either.

If it were my unit, I would ask Rotor to replace it.

[entwistlejon]

Thanks John,

I concur with your findings. I took the Newton out for a ride on my mountain bike yesterday after pairing it with my Stages PM. No problem whatsoever.

Your analysis and yesterday's ride provides enough evidence to suggest the Rotor PM needs further investigation.

Thanks again.