Concept2 Forum

The two model Ds that we have in Basingstoke are quite close together (less than 120cm apart, I've not measured it). When two of us were rowing, both using Polar "coded" chest straps we got some very strange results. Both PM3 where showing HR up above 200.

Our watches were showing more sane values that were unique to each of us. Paul's watch showed his HR, my watch showed mine (as you'd expect).

There seems to be a problem that the PM3 with HR interface can't discriminate between signals from the two straps. Polar have clearly nailed this problem with the "coded" chest strap.

Can you look at making the PM3 sensitive to the chest strap coding?

The other problem I have with the HR interface is that it loses the signal. My watch will be registering a normal value but the HR display goes blank, the little heart winks then the display reappears. (This isn't a problem with not having the contacts wet enough - I could go in for Olympic sweating if they make it a sport for 2008.) The problem seems to be that the PM3 drops the display too soon, it needs to allow more time (more beats missed) before blanking the display.

Can you have a look at improving that too?

* BUMP *

Citroen:

I agree that closely spaced ergs and the Polar HR system is a problem. Unfortunately there is no good solution except moving farther away.

The issue with Polar coded belts is this (someone from Polar can correct me if I'm wrong on any point...)...

1) The Polar Coded belt picks a new "Code" each and every time it powers up.
-> How are you going to know which belt is yours when you are in an environment where there are others? This works well for a watch, you can easily move somewhere outside of the 30" or so range. But, with closely spaced ergs, what are you going to do -- ask the guy to move away? Go through some strange menu selections to tell it to ignore the one it has already sensed from the guy next door and use yours? Take the PM3 off, go somewhere else, pair up with it, and come back?

2) The code is just an extra pulse or pulses at a specific timing.
-> If we have reliability problems with just getting a reliable HR value on the PM (which many customers do), is the coding just going to make it that much harder?

One suggestion from a company that will remain nameless was to put the receiver in the handle (close by to the chest, they claim it will pick up the strongest signal), and run a thin wire (!) alongside the chain to get to the monitor. I can only imagine how long that would last in a club...

In any case, there is soemthing in the works, but I can't talk about it yet...

If the PM3 could be programed to accept the coding the proximity issues is resolved just like it would be with the watches.

The is the first time I have heard a C2 representative state that there have been/are HR reliability issues with the usage of the of the C2 HR interface. As this is apparently a known issue it would have been nice for you to have informed us when it became known rather than waiting until a related question came up.

Dear C2Scott - I have a Model D at home, not near any other rowers, and I have the same problem with my heart-rate monitor. My wearlink (coded) transmitter works fine with my very old Polar (uncoded) wristwatch, but the erg shows 200+ beats per minute. Thus it doesn't appear to be a problem with interference, but with the erg itself. (The erg used to work properly when I had an uncoded transmitter -- alas the batteries died after many years.) This is frustrating: the only reason why I have a hrm is to row.

Gus wrote:The is the first time I have heard a C2 representative state that there have been/are HR reliability issues with the usage of the of the C2 HR interface. As this is apparently a known issue it would have been nice for you to have informed us when it became known rather than waiting until a related question came up.

Seems a bit harsh. The heart rate monitoring function is an add-on relying on 3rd-party equipment at both ends, so it's hardly going to be six sigma. At $25, I reckon it's a pretty good solution for most users most of the time.

Whoha, hold on here....

The reliability issues I refer to, well, I didn't choose the best wording. I've stepped in it and I get the smooth move award for that. Certain things that make electromagnetic fields in the range (or sweep the range) of 5Khz can interfere. A few customers have had to move their stereo's away, or turn them off, or find another offending device. This is no different than any other RF device. Orientation of the receiver is important- follow the directions and it should be good to go.

For the majority of users, the HR stuff works very well. Thousands of folks use it with no problems at all. However, the techology itself has some drawbacks. I should note that Concept2 did not invent this technology. If you have a problem with your HR equipment and the PM2, PM2+, or PM3, please contact us for support and assistance. We're happy to help.

-- Scott

It's really not a C2 problem, it's the limitations of the technology used to give us low cost wireless and more or less reliable data transmission.

For instance if I cross under high voltage transmission lines while running or cycling the Polar HRM shows 0 (zero) HR for the period in the field. If I run or cycle parallel to the high voltage lines, the HRM immediately shows a HR of over 200 for as long as I stay close to the power lines.

This means that some frquencies or intensities of EMF corrupt the data. This can also happen in a gym or home environment.

At home for instance the microwave oven wipes out my WLAN.

c2scott wrote:Whoha, hold on here....

Scott,

I understood your message as meaning that there was a reliability issue with the PM3 and the HR interface. I'm aware of the inherent EMF problems of interference with accurate readings on HR monitors using this technology. Polar cautions us that it can be a problem even with coded chest straps and their watches.

I apologize for my contribution to the misunderstanding.

Gus

Gus:

No problem. Just wanted to put it in perspective.

-- Scott

Getting very worried..

Purchased the Heart Rate Interface.. to work with Model D and PM3.

Just puzzled now. Session 10 x 2,500 1:00r, 20 spm 2:15/500.

Doing 10 pieces today and looking at the outcomes I have a Question as to how the PM3 takes its READINGS.

From the HR for each 10 pieces the outcome was AHR 137, which is the exact figure if I add all 10 results and divide by 10.

No problem there though.

Issue.. During the session I also used my own Polar HR Watch.
During the 'rests' I stopped my Watch and Started again on each Piece.

My HR Watch concluded the AHR for the whole session was 133.. NOT 137.

When I looked closer at the 'PM3 results' I observed that the last Interval Session had a result of 150.. Now this I believe was almost impossible.

I say impossible.. or Wrong as watching the last split which was on the 2,500 interval.. I know I had a HR in the mid/low 140.. However at the END I did do one of those.. Flourishes in last 250 metres and HR did finish at 150/151.. but that was only in last 10% of that final interval.

This raised the Question.. Does PM3 HRI.. take the Last Beat of a piece as the Heart Rate on a split.. or should it be getting an Average from the HR on the whold interval..

I may have missed something.. but it looks that way to me..

And as my watch is saying 133 AHR but PM3 137 it is a big difference

This came to light when checking data from my Log Card.

I am going to run a True TEST tomorrow, doing a very restricted set of 5 minute pieces.. low HR.. and pumping the last 15 seconds.. to test.. if I get a HIGH reading.. then think there is a Problem.

Anyone had similar.. or do I have a dodgy PM3 or HR Interface?

Re Above..

During the whole session.. PM3 HR display and my Polar watch.. were AT ALL Times.. within less than 1 bpm of each other.. so I believe there to be no issue there.

Would have done 'edit' to add this.. but got message saying I can only edit my own posts.. even though it was 'my post'.. Odd.

I believe that your suspicion is correct - that the split HR numbers are in fact the last HR measured when the split ends, not the average for the split.

Is it "wrong"?

Well some would agree with you, while others would say how the PM3 does it is fine.

I wish the average numbers were true averages, but I'm pretty sure the last time this topic went around, the answer was they aren't.

ehagberg

That would be really annoying.. Not that you have said you think it is OK, just some might not worry..

But how could, if it is the case, anyone be happy getting a readng that would be perverted by a 'burp' at the end.. or corrupted by doing a spurt to the finish of an interval.

Really must do a True Test tomorrow.. (Near Midnight UK now)..

Birkyboy wrote:ehagberg

That would be really annoying.. Not that you have said you think it is OK, just some might not worry..

But how could, if it is the case, anyone be happy getting a readng that would be perverted by a 'burp' at the end.. or corrupted by doing a spurt to the finish of an interval.

Really must do a True Test tomorrow.. (Near Midnight UK now)..

It is the ending HR, not an average over the whole segment.

I suspect that no matter which choice the C2 engineers made, there would be people complaining that they wanted the other one. It'd be nice to have both, but either one is a substantial improvement over nothing.

Bill