2.4 PT Dropouts



Thom_y said:
DesFLurane, I couldn't take it anymore ... 8 weeks of Spinervals in the attic is driving me nuts to get back on my bike:

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SO, today for the first time in 15 years, I have managed to ride my old road bike on March 1 OUTSIDE !!!! It was a balmy 1C (-4C windchill) this afternoon when I escaped the hospital to get a real ride (instead of doing the Spinerval Hillacious DVD). I'm impressed, this is the first winter I have taken my trainer sessions more serious with 4 per week x 8 weeks, and it showed on my first 25 mile ride with 1500 feet of hills this afternoon. Unfortunately, a huge storm is hitting tomorrow with snow, rain, and heavy winds. Back to Spinervals this weekend I guess ( my old Trek is back on the trainer)... I have to get ready for my upcoming trip to the bay area, California in May.

Meanwhile, your experience with the new hub is still making me drag my feet on buying my own. Given I don't race and this is for fun only, I may start with the Polar CS600 Power on my new bike and test my aggravation level with that thing ... before taking the big plunge.

Thom
Your indoor setup is making me wish i didn't live in So Cal, where I can ride on the roads year round. I was definitely guessing bachelor pad before your second post. Cheers to the wife for letting you set up shop (although if you have a media room, she prolly has her space too).
Chris
 
Great system.

I have Accoustic Energy fronts and center, Definative Audio surrounds and an SVS PB12 Plus/2. And yes the earth does move;)
 
DesFlurane said:
It has to be a data drop, the transmission indicator goes off as well.
As this seems to only occur at traffic lights, when I'm stationary, I am happy to ignore this 'problem'.
Will email Saris and ask for their take on the issue.
The 26 minute drop, I'm sure I was going passed a speed trap radar!
I'm convinced there are connectivity drops on my 2.4. Also convinced it's not the hub, cad sensor, nor HR strap - it's the Head unit.

For me they seem to happen when cars pass going same direction. Not every car, but it doesn't happen nearly as much in the absence of moving cars (early morn.), so possibly it's radar detectors or the early warning hoosafudge in the newer cars? It happens when I'm moving+pedaling+heart is thumping, so it's not the hub, Cad sens, or strap turning off afaik.

I get drops with both the Data & HR recording settings. On the drops with the HR setting I know the strap was transmitting because my Garmin was recording during that same time. (The 305 picks up the Cycops strap.)


Experiment 1: Eliminate Interference
Add sheilding. <pics>
The 1/4 wavelength of 2.4ghz is somewhere between 35&50mm, so... the mesh is 50mm wide.
Only 1 ride in so far, but results look promising [EDIT: looking at the data, it's too early to tell.]. If it is infact working, I'm not sure if it is actually sheilding oncoming interference or if it's reflecting/concentrating the signal from the hub!?!?

Construction: 50x50mm square boxed around front end + 2ea 50mm long strips on each side.

Pretty crude, but it beats aluminum foil.

ISO.jpg
back.jpg
front.jpg
100_0282.jpg


Layout.jpg



Experiment 2(not started): Boost signal strength
Make a (Wave guide? passive repeater? antenna? whatever it's called) out of coax.
Antenna near hub, antenna near head unit, coax connecting the two.
It's actually redudnant considering the sharkfin that comes with the non 2.4 models, but I doubt Saris will supply one for experimentation.


Thoughts? Comments?
Thanks,
Dave
 
DesFlurane said:
...keep us posted.
Um. Well. At best, it needs work. (Still get drops.) Maybe needs to be grounded to frame?

Possibly different arrangement of shielding? different shielding (Alum foil)?

Oh well, Saris needs to put a better DSP chip on board and redesign the display (Looks like @$$ through Oakley Polarized lens.)

Dave
 
Have you tried mounting the 2.4 computer on your stem? Looking at the photo of your set up you have a couple devices surrounding the PowerTap that won't make it easier for the computer to pick up the hub signal.

When did you purchase your PowerTap 2.4?

Jesse Bartholomew
CycleOps Product Manager
 
powertap said:
Have you tried mounting the 2.4 computer on your stem? Looking at the photo of your set up you have a couple devices surrounding the PowerTap that won't make it easier for the computer to pick up the hub signal.

When did you purchase your PowerTap 2.4?

Jesse Bartholomew
CycleOps Product Manager

Jesse
Out of curiousity, your question regarding when his 2.4 was purchased leads me to beleive that something may have changed from the first production runs to what are being produced today? Is that accurate, or am I misinterpreting why "when" it was purchased makes a differnece?
My vested interest is that I have just ordered a 2.4 from Comp Cyc and if there have been some improvements made, then I would like to know that I have the most recent version.

thanks
Chris
 
Nothing has changed with the product itself but some of our screening processess have improved since the first few units were produced back in November.


cPritch67 said:
Jesse
Out of curiousity, your question regarding when his 2.4 was purchased leads me to beleive that something may have changed from the first production runs to what are being produced today? Is that accurate, or am I misinterpreting why "when" it was purchased makes a differnece?
My vested interest is that I have just ordered a 2.4 from Comp Cyc and if there have been some improvements made, then I would like to know that I have the most recent version.

thanks
Chris
 
Jesse - thanks for quick response - appreciate your input on this forum and other forums.
"Screening" in terms of Quality Assurance?

Have you seen a reduction of service calls for "newer" 2.4 models?

Thanks
chris
 
Yes, we've added additional QA measures to prevent units getting out the door that may be "intermittant."

The volume of service calls was never high, especially when considering how many units we have shipped.

Unfortunately nobody is perfect and, as evidenced by this thread, issues will arise. All we can do is address them as needed and take the necesary steps to ensure nobody else has to deal with it in the field.

cPritch67 said:
Jesse - thanks for quick response - appreciate your input on this forum and other forums.
"Screening" in terms of Quality Assurance?

Have you seen a reduction of service calls for "newer" 2.4 models?

Thanks
chris
 
Thom y-sorry for the late post, but my 20 yr old amp and bookshelf speakers flanking the 27" TV in my training room (basement) just seems so inadequate all of a sudden!!
 
powertap said:
Have you tried mounting the 2.4 computer on your stem? Looking at the photo of your set up you have a couple devices surrounding the PowerTap that won't make it easier for the computer to pick up the hub signal.

When did you purchase your PowerTap 2.4?

Jesse Bartholomew
CycleOps Product Manager
Jesse,

I can understand your troubleshooting question (I'm a systems analyst).

Frankly, I would never mount it to my stem and be satisfied. If I crash the head is vunerable, and when riding in the drops I can't see the display unless it's far enough forward. So the mounting position is not arbitrary for me.

My setup has 3 electronic devices near each other - 2.4 Servo, Garmin 305H/R+CAD, Blackburn LED light.

The garmin only has output to the HR strap (If at all?). Other than that it's a passive RF device.

The light potentially sends out interference - but no apparent correlation between the light's presence (Mounted or not) nor it's operation. I get Servo/Hub drops either way.

As for the QC improvements - I only know when my shop received the hub (02-01-07).

I believe it shipped direct from Saris, but I can check if it helps?
I assume the serial number on Hub/Servo will tell you?
Was the weak link the in the Hub or the Servo?

Thanks for the support!
Dave
 
vladav said:
Frankly, I would never mount it to my stem and be satisfied. If I crash the head is vunerable, and when riding in the drops I can't see the display unless it's far enough forward. So the mounting position is not arbitrary for me.

My setup has 3 electronic devices near each other - 2.4 Servo, Garmin 305H/R+CAD, Blackburn LED light.

The garmin only has output to the HR strap (If at all?). Other than that it's a passive RF device.

The light potentially sends out interference - but no apparent correlation between the light's presence (Mounted or not) nor it's operation. I get Servo/Hub drops either way.

As for the QC improvements - I only know when my shop received the hub (02-01-07).

I believe it shipped direct from Saris, but I can check if it helps?
I assume the serial number on Hub/Servo will tell you?
Was the weak link the in the Hub or the Servo?

Thanks for the support!
Dave
Dave,

Sorry for butting in. I work on wireless stuff for a living.

I agree with Jesse's line of thought 100%. Can you change the mounting position as an experiment? It wouldn't have to be permanent. Just to see the effect on the dropouts.

Also, the first thing that I'd do is turn off all that other electronic stuff on your bars. You say the Garmin is "passive". It's not though, not totally. The receiver can possibly be a source of interference to the 2.4 and, depending upon architecture, it might have a small oscillator inside too. Turn it off.

Both of these need to be evaluated over the preiod of a few hours because your complaint was over a period of hours.

If there's no change in the dropout situation with either or both of these, you're free to go back to how you had it.
 
vladav said:
Experiment 1: Eliminate Interference
Add sheilding. <pics>
The 1/4 wavelength of 2.4ghz is somewhere between 35&50mm, so... the mesh is 50mm wide.
Only 1 ride in so far, but results look promising [EDIT: looking at the data, it's too early to tell.]. If it is infact working, I'm not sure if it is actually sheilding oncoming interference or if it's reflecting/concentrating the signal from the hub!?!?

Construction: 50x50mm square boxed around front end + 2ea 50mm long strips on each side.

Pretty crude, but it beats aluminum foil.

ISO.jpg
back.jpg
front.jpg
100_0282.jpg


Layout.jpg



Experiment 2(not started): Boost signal strength
Make a (Wave guide? passive repeater? antenna? whatever it's called) out of coax.
Antenna near hub, antenna near head unit, coax connecting the two.
It's actually redudnant considering the sharkfin that comes with the non 2.4 models, but I doubt Saris will supply one for experimentation.


Thoughts? Comments?
Thanks,
Dave
Experiment 1: The problem is that depending upon where the interference (if that's the problem) is coming from, you may or may not be helping the situation by putting a shield on only part of the unit. It depends on a few things.

BTW, Lambda/4 in free space is about 31 mm and in copper mesh I think it's more like 41 mm. I'm not sure that you need the shield to be Lambda/4. It's not a quarter- wavelength stub, it's just a shield, which usually can be of arbitrary size, really. (We have whole rooms here at work made of mesh that do the same thing.)

I like your thinking though. If it made a difference, it might lead you in a direction.

Experiment 2: The shark fin antenna was for the "non-wireless" (older) systems. I don't know if they worked at 2.4 GHz as well. (It would be easy to find out though.) If they don't, don't plan on using a shark-fin antenna because it wouldn't be resonant at or near 2.4 GHz. Not only that, how would you plan on attaching to the receiver inside the yellow computer?

If you're going to build a repeater with coax and all that, you're reverting to the old school wired version. It's the same thing. Interesting how things go in cycles, huh?
 
Steve_B said:
Dave,

Sorry for butting in. I work on wireless stuff for a living.

I agree with Jesse's line of thought 100%. Can you change the mounting position as an experiment? It wouldn't have to be permanent. Just to see the effect on the dropouts.

Also, the first thing that I'd do is turn off all that other electronic stuff on your bars. You say the Garmin is "passive". It's not though, not totally. The receiver can possibly be a source of interference to the 2.4 and, depending upon architecture, it might have a small oscillator inside too. Turn it off.

Both of these need to be evaluated over the preiod of a few hours because your complaint was over a period of hours.

If there's no change in the dropout situation with either or both of these, you're free to go back to how you had it.
Do I denote a hint of 'undig your heels sir' (if so it's warranted ;) ) Even so, why would so many others be experiencing similar results?

Thanks for the inputs Steve & Jesse!

Steve,
Plan of action: since everything is wireless - I'll alternate carrying them in my jersey pockets. One on the bar, one in the pocket... agreed? Plenty of distance + water (torso) to attenuate.

It'll take a few days to test thoroughly...

RF science facinates me - it's so messy and clean at the same time :cool:

(BTW, maybe I can bend your ear on PM about our warehouse RF challenges :rolleyes: )
 
Steve_B said:
I don't know if they worked at 2.4 GHz as well. (It would be easy to find out though.) If they don't, don't plan on using a shark-fin antenna because it wouldn't be resonant at or near 2.4 GHz. Not only that, how would you plan on attaching to the receiver inside the yellow computer?

If you're going to build a repeater with coax and all that, you're reverting to the old school wired version. It's the same thing. Interesting how things go in cycles, huh?
Yeah easy to find out - hoping I don't have to...

I was hoping/guessing that the same circutry to recieve the wired signal from the Sharkfin is still there in the 2.4 servo. The pins are there for the cradle upload...

Attaching a reciever? (Probably applying practical knowledge to my guesswork? See how you are!) If you have a stub at one end and a stub at the other, you will get a transmission, correct? (Albeit with a ton of db loss.) That's what I was thinking anyways...
 
Okay well I really only have 2 test rides: Not enough for anything conclusive but interesting nonetheless.

03-11-07, placed Garmin in jersey pocket, left the Servo in my normal handlebar postion (Ref pics above.) For first half of ride power cable to light was disconnected, for second half the light was connected and turned on.

03-13-07, placed the Servo in my seat pack. (Specalized narrow pack contents: 1 tube, 1 CO2, 2 plastic levers.) Garmin on handlebar.
The orientation of the servo was: display facing hub. Drawing imaginary line perp from face would intersect ground perhaps a foot or two behind contact patch. So display facing down and back.

Should mention I have 2 cadence sensors placed on chain stay. Garmin(over)/PT(under).

WKO+ Ride files attached(remove .txt extension). The gaps are already picked out and saved with detail of where, when, what, etc.
(I’m assuming all use WKO+. If not I can post text.)

03-11: 2:20 Hour ride; 12 drops, 8.8 minutes lost data.
MotionBased GPS dashboard for 03-11 test

03-13: 1:09 hour ride; 7 drops (The first one only kindof counts, I’ll give it a mulligan), 1.7 minutes missed data.
MotionBased GPS dashboard for 03-13 test
This was the first time I noticed data other than power within a gap. Notably cadence. I’m led to believe that the cadence snsr has a relatively weak signal too since it had to be so close to the Servo.
HR would have been sporadic since the strap didn’t have LoS. (Same w/garmin in pocket.)

It is weird how some gaps are minutes long but when selected only add up to a single data point (1.x seconds.) Maybe a WKO+ thing?


IMPORTANT: this time I did not wear my tin foil heat-conduction layer between helmet and head… (just 3 pocket protectors for jersey pockets – Gu in pocket = yuk.)

Regards,
Dave
 
sorry to chime in so late,but I have had intermittent drops with my 2.4 but didn't want to send it in. Any advice as to wether this would actually help and/or what the turn around is.
 
hallo from Germany,

I'am using a PT 2.4 since 2 weeks druing 9 rides and 850 km. During the first 7 rides, when I was using a Garmin 301 simultaniously, I had about 10 dopouts of the hub per hour but no dropout of the heard rate. On the weekend the Garmin stayed at home and astonishing I had only 9 short hub drop outs (shorter than 3 seconds) during 9 hours ride.
 
To be clear there is no interference issue, it is an RF power issue on the hub end of things. This is why position of the Computer is important in this particular case as the hub cannot be moved.

Despite this obviously being a unit in need of repair, I'll offer some additional experimentation ideas since you seem to be game.
  1. Put the computer on the stem or the left part of your bar (in the photos you don't have anything there) The antenna in the computer is somewhat positional, this is why putting it in the back packet may not work so well. In addition, the computer doesn't like to be too close to humans.
  2. Try putting it back int he saddle pack WITHOUT anything else in it (no CO2, tube etc)
  3. Mount the CPU on your top tube.
Again, these aren't things that we would have the typical customer do but in the name of experimentation it could be interesting.

Jesse Bartholomew
PowerTap Product Manager


vladav said:
Okay well I really only have 2 test rides: Not enough for anything conclusive but interesting nonetheless.

03-11-07, placed Garmin in jersey pocket, left the Servo in my normal handlebar postion (Ref pics above.) For first half of ride power cable to light was disconnected, for second half the light was connected and turned on.

03-13-07, placed the Servo in my seat pack. (Specalized narrow pack contents: 1 tube, 1 CO2, 2 plastic levers.) Garmin on handlebar.
The orientation of the servo was: display facing hub. Drawing imaginary line perp from face would intersect ground perhaps a foot or two behind contact patch. So display facing down and back.

Should mention I have 2 cadence sensors placed on chain stay. Garmin(over)/PT(under).

WKO+ Ride files attached(remove .txt extension). The gaps are already picked out and saved with detail of where, when, what, etc.
(I’m assuming all use WKO+. If not I can post text.)

03-11: 2:20 Hour ride; 12 drops, 8.8 minutes lost data.
MotionBased GPS dashboard for 03-11 test

03-13: 1:09 hour ride; 7 drops (The first one only kindof counts, I’ll give it a mulligan), 1.7 minutes missed data.
MotionBased GPS dashboard for 03-13 test
This was the first time I noticed data other than power within a gap. Notably cadence. I’m led to believe that the cadence snsr has a relatively weak signal too since it had to be so close to the Servo.
HR would have been sporadic since the strap didn’t have LoS. (Same w/garmin in pocket.)

It is weird how some gaps are minutes long but when selected only add up to a single data point (1.x seconds.) Maybe a WKO+ thing?


IMPORTANT: this time I did not wear my tin foil heat-conduction layer between helmet and head… (just 3 pocket protectors for jersey pockets – Gu in pocket = yuk.)

Regards,
Dave