Polar wireless speed transmitter w S-710

I have a speed sensor with my Polar S710 (and a previous model as well). I
have always had to correct a few spikes in velocity which is not a problem
for me. I also use a hard wired computer to avoid toggling for data while
riding. Both devices are always very close in total distance and ride time.

Lately, (the past week or so) I have had the number of spikes that need
correction go way up. I now have to correct 10 or more per hour (out of 180
samples) which is still not bad but it is annoying. BTW, sampling at 5
seconds makes it very unlikely that it will ever be off by any significant
amount. I never have any errors adjacent to one another. I still want to
look in to improving this. I recall that there is a switch in some of these
Polar wireless units. I have both old and new styles for cadence and speed.
I almost never have any problems with cadence. I guess I should note that I
have the watch mounted on a 90 degree stem stub about 7 cm past the fork.
This puts it nearly directly above the speed sensor and about 20 cm forward
or the cadence sensor. I realize that Polar has purposely made these
transmitter somewhat directional and that the "sweet spot" for transmission
may not be what seems most obvious.

I would like to know which transmitters can be adjusted for signal strength
and how to determine the ideal transmission and reception angle for all of
them. I did experiment with moving the watch all over and it had almost no
effect. I think that my next move WRT transmission is changing the angle of
the transmitter but I would like to know how the antennae is mounted
internally. If I don't hear from anyone, I suppose I can crack them both
open and see what I find.

Thanks for any help.

"Chris" wrote in message
...
I have a speed sensor with my Polar S710 (and a previous model as well). I
have always had to correct a few spikes in velocity which is not a problem
for me. I also use a hard wired computer to avoid toggling for data while
riding. Both devices are always very close in total distance and ride
time.

Lately, (the past week or so) I have had the number of spikes that need
correction go way up. I now have to correct 10 or more per hour (out of
180
samples) which is still not bad but it is annoying. BTW, sampling at 5
seconds makes it very unlikely that it will ever be off by any significant
amount. I never have any errors adjacent to one another. I still want to
look in to improving this. I recall that there is a switch in some of
these
Polar wireless units. I have both old and new styles for cadence and
speed.
I almost never have any problems with cadence. I guess I should note that
I
have the watch mounted on a 90 degree stem stub about 7 cm past the fork.
This puts it nearly directly above the speed sensor and about 20 cm
forward
or the cadence sensor. I realize that Polar has purposely made these
transmitter somewhat directional and that the "sweet spot" for
transmission
may not be what seems most obvious.

I would like to know which transmitters can be adjusted for signal
strength
and how to determine the ideal transmission and reception angle for all of
them. I did experiment with moving the watch all over and it had almost no
effect. I think that my next move WRT transmission is changing the angle
of
the transmitter but I would like to know how the antennae is mounted
internally. If I don't hear from anyone, I suppose I can crack them both
open and see what I find.

Thanks for any help.



I also have had spikes with my Polar S710, and they are always in the same
place on one particular part of one of my training ride. My unit spikes
with the cadence, speed, heart rate, and altitude. The errors can be
corrected, usually it's one - three sections together. I believe I narrowed
it down to the signal light transmitter sensor for changing stop lights at
the turnaround junction of my training ride. At this junction, I'm usually
in the left had turning lane, waiting for the light to turn green to make a
u-turn.

Just curious, do your spikes occur near long stoplight?
-tom

"Chris" wrote in message
...
I have a speed sensor with my Polar S710 (and a previous model as well). I
have always had to correct a few spikes in velocity which is not a problem
for me. I also use a hard wired computer to avoid toggling for data while
riding. Both devices are always very close in total distance and ride
time.

Lately, (the past week or so) I have had the number of spikes that need
correction go way up. I now have to correct 10 or more per hour (out of
180
samples) which is still not bad but it is annoying. BTW, sampling at 5
seconds makes it very unlikely that it will ever be off by any significant
amount. I never have any errors adjacent to one another. I still want to
look in to improving this. I recall that there is a switch in some of
these
Polar wireless units. I have both old and new styles for cadence and
speed.
I almost never have any problems with cadence. I guess I should note that
I
have the watch mounted on a 90 degree stem stub about 7 cm past the fork.
This puts it nearly directly above the speed sensor and about 20 cm
forward
or the cadence sensor. I realize that Polar has purposely made these
transmitter somewhat directional and that the "sweet spot" for
transmission
may not be what seems most obvious.

I would like to know which transmitters can be adjusted for signal
strength
and how to determine the ideal transmission and reception angle for all of
them. I did experiment with moving the watch all over and it had almost no
effect. I think that my next move WRT transmission is changing the angle
of
the transmitter but I would like to know how the antennae is mounted
internally. If I don't hear from anyone, I suppose I can crack them both
open and see what I find.

Thanks for any help.



I also have had spikes with my Polar S710, and they are always in the same
place on one particular part of one of my training ride. My unit spikes
with the cadence, speed, heart rate, and altitude. The errors can be
corrected, usually it's one - three sections together. I believe I narrowed
it down to the signal light transmitter sensor for changing stop lights at
the turnaround junction of my training ride. At this junction, I'm usually
in the left had turning lane, waiting for the light to turn green to make a
u-turn.

Just curious, do your spikes occur near long stoplight?
-tom

Tom Nakashima wrote:
"Chris" wrote in message
...
Just curious, do your spikes occur near long stoplight?
-tom

Or Powerlines.
Yes my spikes too are always at the same place of my ride. As I pass
underneath some powerlines. Interestingly enough I can pass under other
powerllines that do not produce any spikes.

--
Perre

You have to be smarter than a robot to reply.

Tom Nakashima wrote:
"Chris" wrote in message
...
Just curious, do your spikes occur near long stoplight?
-tom

Or Powerlines.
Yes my spikes too are always at the same place of my ride. As I pass
underneath some powerlines. Interestingly enough I can pass under other
powerllines that do not produce any spikes.

--
Perre

You have to be smarter than a robot to reply.

"Tom Nakashima" wrote in message


The errors can be
corrected, usually it's one - three sections together.

I know. Luckily my cadence does not spike and neither does heart rate.

I believe I narrowed
it down to the signal light transmitter sensor for changing stop lights at
the turnaround junction of my training ride. At this junction, I'm
usually
in the left had turning lane, waiting for the light to turn green to make
a
u-turn.

Just curious, do your spikes occur near long stoplight?
-tom

No, it is definitely unrelated to external interference. It even happens on
country roads miles from any EMF. I tend to think that somehow the speed
"pulse" gets interpreted by the receiver twice on a single wheel rev. I
think that if the signal is somehow interrupted and then restored all while
the transmitter is broadcasting its signal for that rev, that would account
for this. If this sounds too illogical let me explain it with an example.
Let's say that each pulse lasts 5/100s of a second. The whole system has to
have some fault tolerance so a signal that is too short is less likely to
get through. Again for fault tolerance and to keep costs down the receiver
does not care how long the signal is. It also is not set to reject any
signals no matter how close together they are. Now add to that a case where
the reception is marginal but still persistent. In cases where the spike
occurs, I am moving along and the transmitter is constantly changing its
placement relative to the receiver slightly. The transmitter sends its
signal for 5/100s and the receiver picks it up for the first (or second or
whatever) and then loses it but catches that last fraction. It counts it
twice since it recorded to pulses. Also keep in mind that most of the time
in a case like this, you would probably be persistently getting much less of
the signal than that ideal 5/100 of a second. If the signal is lost at the
beginning or the end or even on the middle, as long as it is not restored
before it completes it broadcast it will count it accurately. I think this
also explains why there is an interest in digital wireless cyclometers.

I don't know how long each signal pulse is sent but this is really the only
logical way that these spikes can occur that I can think of. It never drops
data, it always comes up with an extra. Also, the amount it is off is always
equal to one extra rev.

I think if I do everything I can to ensure each pulse is received as one
(and not split) then I should be good. That is why I am looking at signal
strength and optimal direction.

"Tom Nakashima" wrote in message


The errors can be
corrected, usually it's one - three sections together.

I know. Luckily my cadence does not spike and neither does heart rate.

I believe I narrowed
it down to the signal light transmitter sensor for changing stop lights at
the turnaround junction of my training ride. At this junction, I'm
usually
in the left had turning lane, waiting for the light to turn green to make
a
u-turn.

Just curious, do your spikes occur near long stoplight?
-tom

No, it is definitely unrelated to external interference. It even happens on
country roads miles from any EMF. I tend to think that somehow the speed
"pulse" gets interpreted by the receiver twice on a single wheel rev. I
think that if the signal is somehow interrupted and then restored all while
the transmitter is broadcasting its signal for that rev, that would account
for this. If this sounds too illogical let me explain it with an example.
Let's say that each pulse lasts 5/100s of a second. The whole system has to
have some fault tolerance so a signal that is too short is less likely to
get through. Again for fault tolerance and to keep costs down the receiver
does not care how long the signal is. It also is not set to reject any
signals no matter how close together they are. Now add to that a case where
the reception is marginal but still persistent. In cases where the spike
occurs, I am moving along and the transmitter is constantly changing its
placement relative to the receiver slightly. The transmitter sends its
signal for 5/100s and the receiver picks it up for the first (or second or
whatever) and then loses it but catches that last fraction. It counts it
twice since it recorded to pulses. Also keep in mind that most of the time
in a case like this, you would probably be persistently getting much less of
the signal than that ideal 5/100 of a second. If the signal is lost at the
beginning or the end or even on the middle, as long as it is not restored
before it completes it broadcast it will count it accurately. I think this
also explains why there is an interest in digital wireless cyclometers.

I don't know how long each signal pulse is sent but this is really the only
logical way that these spikes can occur that I can think of. It never drops
data, it always comes up with an extra. Also, the amount it is off is always
equal to one extra rev.

I think if I do everything I can to ensure each pulse is received as one
(and not split) then I should be good. That is why I am looking at signal
strength and optimal direction.

"Per Elmsäter" wrote in message
...
Tom Nakashima wrote:
"Chris" wrote in message
...
Just curious, do your spikes occur near long stoplight?
-tom

Or Powerlines.
Yes my spikes too are always at the same place of my ride. As I pass
underneath some powerlines. Interestingly enough I can pass under other
powerllines that do not produce any spikes.


As I said, I get them even when there is nothing around to give EMF. It
tends to happen more at speed on rough roads (oscillation?). I think I might
try to look for other patterns.

"Per Elmsäter" wrote in message
...
Tom Nakashima wrote:
"Chris" wrote in message
...
Just curious, do your spikes occur near long stoplight?
-tom

Or Powerlines.
Yes my spikes too are always at the same place of my ride. As I pass
underneath some powerlines. Interestingly enough I can pass under other
powerllines that do not produce any spikes.


As I said, I get them even when there is nothing around to give EMF. It
tends to happen more at speed on rough roads (oscillation?). I think I might
try to look for other patterns.

Chris wrote:
"Tom Nakashima" wrote in message


The errors can be
corrected, usually it's one - three sections together.

I know. Luckily my cadence does not spike and neither does heart rate.

I believe I narrowed
it down to the signal light transmitter sensor for changing stop
lights at the turnaround junction of my training ride. At this
junction, I'm usually in the left had turning lane, waiting for the
light to turn green to make a u-turn.

Just curious, do your spikes occur near long stoplight?
-tom

No, it is definitely unrelated to external interference. It even
happens on country roads miles from any EMF. I tend to think that
somehow the speed "pulse" gets interpreted by the receiver twice on a
single wheel rev. I think that if the signal is somehow interrupted
and then restored all while the transmitter is broadcasting its
signal for that rev, that would account for this. If this sounds too
illogical let me explain it with an example. Let's say that each
pulse lasts 5/100s of a second. The whole system has to have some
fault tolerance so a signal that is too short is less likely to get
through. Again for fault tolerance and to keep costs down the
receiver does not care how long the signal is. It also is not set to
reject any signals no matter how close together they are. Now add to
that a case where the reception is marginal but still persistent. In
cases where the spike occurs, I am moving along and the transmitter
is constantly changing its placement relative to the receiver
slightly. The transmitter sends its signal for 5/100s and the
receiver picks it up for the first (or second or whatever) and then
loses it but catches that last fraction. It counts it twice since it
recorded to pulses. Also keep in mind that most of the time in a case
like this, you would probably be persistently getting much less of
the signal than that ideal 5/100 of a second. If the signal is lost
at the beginning or the end or even on the middle, as long as it is
not restored before it completes it broadcast it will count it
accurately. I think this also explains why there is an interest in
digital wireless cyclometers.

I don't know how long each signal pulse is sent but this is really
the only logical way that these spikes can occur that I can think of.
It never drops data, it always comes up with an extra. Also, the
amount it is off is always equal to one extra rev.

I think if I do everything I can to ensure each pulse is received as
one (and not split) then I should be good. That is why I am looking
at signal strength and optimal direction.

As far as signal strength goes it's easy to fix.

Open up the speed or cadence sensor with a very small Philips screwdriver.
Make sure it fits well before you start turning. The screws are located in
such a way that you have to remove the sensor from the bike to get at them.
Once it's open you will find a whachamacallit. Hmm. It's like a little
bridge between two contact points. It can be set in three positions.
I think if it's connecting the two outside pins you have the strongest
transmission. Remember that battery will wear out faster.
If you want to check the exact settings you can probably find them here.
http://www.pursuit-performance.com.a...um/dcboard.cgi


--
Perre

You have to be smarter than a robot to reply.