Rich

I have just installed a Standard Horizon Chart plotter - CP 180. Very
pleased with it except for one function - the Trip Log. It reads
around 160 - 175% of the actual true log. The plotter measures
distances to waypoints apparently accurately but based on speed over
ground and time and referring to hand held Garmin GPS it is widely
out with trip log. IThis is one of my favourite log measurements and I
wonder if anyone else had encountered similar or who had an idea what
was happening
Thanks
Rich
Westerly 2219 DAVICO

Wilbur Hubbard

"Rich" <richard.bird2@btinternet.com> wrote in message
news0d9b319pibdmre2svr6823dn74mkaiouv@4ax.com...
>I have just installed a Standard Horizon Chart plotter - CP 180. Very
> pleased with it except for one function - the Trip Log. It reads
> around 160 - 175% of the actual true log. The plotter measures
> distances to waypoints apparently accurately but based on speed over
> ground and time and referring to hand held Garmin GPS it is widely
> out with trip log. IThis is one of my favourite log measurements and I
> wonder if anyone else had encountered similar or who had an idea what
> was happening
> Thanks
> Rich
> Westerly 2219 DAVICO

Try setting it to nautical miles. It sounds like it's set to kilometers.
About the right error range, at least.

Wilbur Hubbard

Rich

On Sat, 4 Aug 2007 14:09:16 -0400, "Wilbur Hubbard"
<wilburhubbard@thefarm.invallid> wrote:
Exactly what I thought but checked this many times. The only thought
which sounds a little stupid is that the plotter has actually got it
marked the wrong way eg nm mixes with km but that would be a universal
fault. Thanks and please keep suggestions coming
Rich
>
>"Rich" <richard.bird2@btinternet.com> wrote in message
>news0d9b319pibdmre2svr6823dn74mkaiouv@4ax.com.. .
>>I have just installed a Standard Horizon Chart plotter - CP 180. Very
>> pleased with it except for one function - the Trip Log. It reads
>> around 160 - 175% of the actual true log. The plotter measures
>> distances to waypoints apparently accurately but based on speed over
>> ground and time and referring to hand held Garmin GPS it is widely
>> out with trip log. IThis is one of my favourite log measurements and I
>> wonder if anyone else had encountered similar or who had an idea what
>> was happening
>> Thanks
>> Rich
>> Westerly 2219 DAVICO
>
>Try setting it to nautical miles. It sounds like it's set to kilometers.
>About the right error range, at least.
>
>Wilbur Hubbard

Westerly 2219 DAVICO

Cathy

You mention only just installing the unit. Have you had this problem on only
one trip so far or does this happen continually?

Can you download the track from the unit and that from your handheld unit
onto PC chartplotter to compare where the differences are?

Regards
C

Rich

On Mon, 27 Aug 2007 12:01:10 +0100, "Cathy" <Cathy@Nospam.com> wrote:
All the time even when Im not moving. However Standard Horizon are
being very helpful and we are going to reinstall the firmware and see
how we go from there.

Thanks for your help all sounds a bit too technical for me LOL

Rich
>You mention only just installing the unit. Have you had this problem on only
>one trip so far or does this happen continually?
>
>Can you download the track from the unit and that from your handheld unit
>onto PC chartplotter to compare where the differences are?
>
>Regards
>C
>

Westerly 2219 DAVICO

Ronald Raygun

Rich wrote:

> On Mon, 27 Aug 2007 12:01:10 +0100, "Cathy" <Cathy@Nospam.com> wrote:
> All the time even when Im not moving.

There's your answer, then. If it's clocking up distance travelled
while you're not actually moving, it must not be doing the averaging
to filter out the distance between successive instantaneous fixes,
i.e. as your position jumps about by perhaps a few tens of m every
second or less, each of these false leaps is added to your trip.

Ronald Raygun

Ronald Raygun wrote:

> Rich wrote:
>
>> On Mon, 27 Aug 2007 12:01:10 +0100, "Cathy" <Cathy@Nospam.com> wrote:
>> All the time even when Im not moving.
>
> There's your answer, then. If it's clocking up distance travelled
> while you're not actually moving, it must not be doing the averaging
> to filter out the distance between successive instantaneous fixes,
> i.e. as your position jumps about by perhaps a few tens of m every
> second or less, each of these false leaps is added to your trip.

I should have added that my Lowrance 3500 does something similar
(failing to average its position). I've not checked whether it
affects trip distance, but it certainly affects its display of
ETA at (or time to go to) next waypoint, which jumps about madly
every few hundred milliseconds even when one's speed is fairly
steady. It appears to be extrapolating the speed computed from
its latest two instantaneous fixes.

Makes you wonder who they get to write their firmware.
Must be computing undergraduates during their summer holidays.