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General Category => General Discussion => Topic started by: Moto on May 25, 2016, 10:16:32 AM
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Has anyone successfully installed and calibrated a magnetic (and non-digital) compass on an old Tonti that doesn't have a fairing?
I'd like to do just that. I installed one like this
(http://i127.photobucket.com/albums/p135/motocomo/Bell%20Automotive%20compass.png)
http://www.amazon.com/Bell-Automotive-22-1-24000-8-Traveler-Compass/dp/B000FW2MCM (http://www.amazon.com/Bell-Automotive-22-1-24000-8-Traveler-Compass/dp/B000FW2MCM)
in the fairing of my old '83 Yamaha Vision, and successfully calibrated it with the built-in compensators. By success, I mean that it worked pretty well, so that it was off by less than a sixteenth of the dial everywhere (maybe an eighth).
But trying to put one on my unfaired T3 has been unsuccessful. A magnetometer (app, in my phone) goes nuts around the handlebar area, even with the engine turned off. I vaguely recall having tried and failed to calibrate the same model of compass on it some time back.
Any suggested solutions?
Please don't suggest a GPS; I have one I don't want to use! Please don't tell me you're happy with an uncompensated compass you strapped around your handlebars or keep in your pocket; I wouldn't be! And please don't turn this thread into another pointless GPS vs. maps-and-a-compass debate! :rolleyes:
Thanks,
Moto
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:popcorn:
Dusty
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Nope on the compass but I know some stuff about the Yamaha fairing :thumb:
(http://thumb.ibb.co/fGr4Jv/image.jpg) (http://ibb.co/fGr4Jv)
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When you installed it in the Yam fairing was it located a distance from any significant amount of steel? That may be the difference.
It is very difficult to calibrate a magnetic compass when it is mounted on a lump of steel. If you can move it even a few inches away you'll have better luck.
PS no, I have not tried to mount a mag compass like that in decades. Learned land nav in the hatch of a 60 ton tank so did most of that without a compass.
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Nope on the compass but I know some stuff about the Yamaha fairing...
I'd like to know more about your installation! I've got a spare Vision fairing I've been wanting to mount on my T3, though I'd want to be able to remove it easily. (That's probably going to be the permanent deal-breaker.) Maybe another thread would be appropriate.
When you installed it in the Yam fairing was it located a distance from any significant amount of steel? That may be the difference.
It is very difficult to calibrate a magnetic compass when it is mounted on a lump of steel. If you can move it even a few inches away you'll have better luck.
That's what I was trying to imply, I guess. I recognize the problem and mounted the Vision's compass as far from steel as I could. Short of installing such a fairing on the T3, though, there's not much that's not steel to mount a compass on!
PS no, I have not tried to mount a mag compass like that in decades. Learned land nav in the hatch of a 60 ton tank so did most of that without a compass.
Perhaps tank navigation methods would work better! Any ideas there?
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Have you thought about demagnetizing the offending metal. Maybe the handlebars.
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Welded aircraft fuselages share this same problem. There is a degaussing (sp?) tool that to be used on antique televisions. A guy can make one, but I don't remember much except a bunch of copper wire and a power source. No doubt Google will tell you all about it.. but yes, you need to demagnetize the area around the compass if possible.
I didn't have any luck doing it on the Piper Colt I rebuilt, though.. and Piper apparently didn't either. They took the compass out of the panel and mounted it on the glare shield. Works ok up there.. maybe 4 inches away from the panel structure. <shrug>
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I once had the unfortunate experience of trying to figure this out on a nonpaying customer's bellanca scout. It seems the gear had been recently magnafluxed after an accident and were really "magneti". What helped was to hook the ground of an ac welder to one gear leg and clamp a piece of steel to the fartest away point of the other gear leg and strike a few arcs. Got rid of about 2/3 of the magnetism I recon. Make sure anything with diodes (alternator) in it is disconnected before attempting though. My feeling is that if the gps had been around in ancient times they never would have invented the compass.
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Go to this web site www.formotionproduc ts.com. and look at their black compass, its a winner, no battery's thank you!
Aerostich sells it for $65 but its cheaper ($50?) direct from them.
Thanks, Kirby. I just ordered one from Formotion for $50 plus shipping.
BTW, Formotion's web site says they are getting out of retail in general (including through distributors), so all their remaining stock is on sale. (Aerostich, Amazon, and Dennis Kirk are all out of stock on the compass.) Anyone else interested in some of their nice-looking accessories should act quickly.
I'll hope the compass works as well for me as for Kirby. My fall-back device is a sun compass I designed yesterday, but haven't built!
Thanks to all the others who replied -- helpful and on-point every one of you.
Moto
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I have used a soldering gun as a degausing coil many times. The field is much lighter than the regular coil that I have but when the coil is 50 miles away the soldering gun works fine.
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Perhaps tank navigation methods would work better! Any ideas there?
Yep, map and navigate by landmarks. Good topo map for off road. On road you need to find a GOOD map, not the usual gas station type. AAA makes decent ones. I also like the ones labeled "Recreation" maps for different states.
FWIW, the only time any of this has failed me is when the fog is thick enough not to see the front of my vehicle, or it is so dark out you litterally cannot see your hand in front of your face (yes, has happened to be twice).
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I have used a soldering gun as a degausing coil many times. The field is much lighter than the regular coil that I have but when the coil is 50 miles away the soldering gun works fine.
Using the method in this youtube video?
https://www.youtube.com/watch?v=jTbkP9khh2c (https://www.youtube.com/watch?v=jTbkP9khh2c)
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Great Moto!
I used their mount on the handlebar which elevates it away from the bar and the bolts for the bar clamp.
I figure I'll use the aluminum clamp that came with the little black clock I just installed, as mentioned in a recent thread. (Saving the $19.95 for Formotion's clamp!)
I'm sure you know this but I will mention that when traveling, the declination (magnetic) can cause errors in the areas your riding thru. So if your heading directly into the sun mid summer and the compass is 10 degrees off you are probably in an area of high declination.
Another thing that I keep in mind is that the sun is not always due west as it sets -- in midsummer it sets north of west. This plot shows the story (for 50 some odd degrees north latitude):
(http://i127.photobucket.com/albums/p135/motocomo/azimuthal_sundial.png)
This can account for the 10 degrees you mention, apart from any local changes in magnetic declination. (I came across this particular plot while researching my sun compass.)
Moto
P.S. That plot is for a so-called azimuthal sundial, and is confusing at first, so I'll explain. Use the central compass dial to read the directions of the sun at different times of day for the different months. The highest light blue line on the left part of the graph traces the bearing of the sun at 6pm (solar time) for the different months. It shows the sun is about 15 degrees north of west at 6pm in June or July at that particular latitude. How the solar time corresponds to clock time is another part of the story. The topmost of the curved lines on the left shows the bearing at sunset, which occurs at different times through the year. In June/July the sun sets almost due northwest at that latitude.
The East and West notations on the outside of the plot, on the other hand, show how the (horizontal) sundial face should be oriented.
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Try one of these stuck on the gas tank
http://www.oreillyauto.com/site/c/detail/CA00/55558/N0344.oap?ck=Search_compass%21s%21thermometer_-1_4788&keyword=compass%21s%21thermometer
worked on my old Honda long enough to get from California to Michigan.
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Thanks, Kirby. I just ordered one from Formotion for $50 plus shipping.
I hope you have better luck with Formation than I did with their garbage.
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Hey all,
I'm hoping I'll have Kirby's luck with the compass. I'll report back when I get it mounted and calibrated. I'm pretty confident in his recommendation.
If OMG has anything specific to report, that's fine. But for me the die is cast.
Moto
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Thanks , have not seen one of those in a long time. I was thinking about the way I travel east and west mid summer, and at the mid 30's the sun is pretty much dead east and west(sun rise to sun set), It will throw some in confusion as to the compass has gone nuts..
Any way good luck, I hope you share your experience when done.
:-)
I appreciate your comment about the difference in sunset direction at different latitudes. I hadn't been thinking about that really. So I looked up a formula to make the calculation of the bearing of the sun at sunset. This formula has nothing to do with local clock time nor with longitude, so it is less complicated than calculating the bearing of the sun at, say, 6pm local time. It turns out 35 and 45 degrees north latitude both round to the same compass point, WNW, at the summer solstice. But the bearing is another point south at 25N. Here are my calculations.
(http://i127.photobucket.com/albums/p135/motocomo/sunset%20bearings%20at%20summer%20solstice.png)
Anyway, thanks again for your thoughtful comment.
Moto
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If OMG has anything specific to report, that's fine. But for me the die is cast.
Long story. I posted here years ago. In the end, I had purchased two clocks and two thermometers. Not cheap. Within a year, only one thermometer was still working and Formation's answer was for me to buy another set. Their equipment failed early and the warranty is worthless.
On the other hand, I have an identical looking off brand clock and thermometer that I bought for my Centauro over 15 years ago for $15. It is still seeing daily use on my EV. No issues.
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" Perhaps tank navigation methods would work better! Any ideas there? "
Talk about point and shoot...
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im fairly sure the speedo and tach have magnets in them that spin round and round ..... prob not going to help the compass..
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Hi Moto,
I'll be interested to see how you get on with this. It is I think, likely to be hard to do with any accuracy. Not only are you trying to mount a compass on a great lump of steel, you have all manner of flying magnets and un shielded electrical currents in the near vicinity.
When you add in localised variations due to geography, (and other traffic maybe) well, best of luck.
Of course it is successfully done on steel boats, but they almost inevitably have all things electrical shielded to the hilt and are somewhat less subject to localised magnetic anomalies than a land based vehical would be. None the less, I suspect your best chance of success would be to consult with marine compass people.
What interests me more I must admit, given that North can be readily established using an analog watch during the day and the stars by night, as long as the sky isn't too clagged in, is why you would want to do this.
Even with a heavily overcast sky navigation can usually be successfully achieved by noting landmarks, and if the need for a compass was really felt, a circumstance that seems to me to be unlikely at best, surely a decent hand one used well away from the bike would be the most effective answer.
So I'm curious Moto. What's the go here?
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Hi Moto,
I'll be interested to see how you get on with this. It is I think, likely to be hard to do with any accuracy....
So I'm curious Moto. What's the go here?
Hi John,
My motivation is all the small, winding roads we have here in western Wisconsin. I often get mixed up in my directions and find myself not knowing which way to turn at the next stop sign.
I just want to glance at a compass at a stop sign, and turn the right direction. Or I want to glance at the compass while approaching an unknown crossroad and decide whether it leads toward home (for example) and whether I should give it a try. These kinds of situations are not ones where I want to get off my bike and consult a hand compass, or even stop and roll up my sleeve.
I'll report how it works out.
Moto
[Edited for length.]
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OK Moto, sounds reasonable and I look forward to the result. I'm probably forgetting that you live in a far more extensive land than I, or perhaps it's just the nature of your area.
You know, the yacht I used to sail (an international Dragon)out of Lyttelton (Port of Christchurch) had had its compass removed. I bought it's owner a cheap car one for Christmas along with some other goodies I thought we should have. It would in no way be considered a steerage compass but we reckoned if we got caught out by one of the sea fogs that occurred from time to time in the area, we would have to head off shore. Afterward though at least we would be able to find the South Island.
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I'm the OP, interested in a magnetic compass, but want to post this related product discovery before I forget to.
Marlin, a maker of motorcycle clocks, thermometers and magnetic compasses, is about to offer this gps-based motorcycle compass: http://marlinsclocks-net.3dcartstores.com/Marlins-Quest-Compass--Satellite-Driven_p_270.html (http://marlinsclocks-net.3dcartstores.com/Marlins-Quest-Compass--Satellite-Driven_p_270.html)
(http://i127.photobucket.com/albums/p135/motocomo/Marlin%20Quest%20GPS%20Compass.png)
It looks pretty much like a magnetic compass, mounting on the handlebar. But it uses GPS signals to determine the vehicle's direction within an eighth of the dial: N, NE, E, SE, S, SW, W, NW, N.
I'd been wondering if such a thing had ever been made, and now here it is. I spoke to the developer today, who said it should be ready for sale next week. The case diameter is 1 3/4", and the compass requires external power, either 9v battery or 5v USB (and maybe 12v, I think). The price is about $140.
This would avoid the magnetic compensation problem entirely, and as the developer said, requires no subscription to use, unlike a cellphone. I don't know anything about its quality and reliability though. I'm sticking with my magnetic compass, and I'll post an update about that.
Just thought I'd pass this along. If anyone buys one, by all means post your experience with it.
Moto
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Analogue watch and a sextant. What could go wrong? :evil:
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So, have you ever seen a compass binnacle on a steel boat? With the two huge steel orbs on either side.. THAT is how you swing a compass on a ferrous metal vehicle/boat... You could attempt to do it on a Tonti frame, but you would be chasing it around trying to compensate and I don't think the compensation magnets inside most analogue compasses would have enough to offset the steel tonti frame. The GPS compass is better it's not really a compass.. It's a direction of movement display.. Not a which way are you pointing display.
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I'm the OP, interested in a magnetic compass, but want to post this related product discovery before I forget to.
Marlin, a maker of motorcycle clocks, thermometers and magnetic compasses, is about to offer this gps-based motorcycle compass...
All well and good as long as you're moving. Completely useless when stopped, unless it has a magnetic backup.
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The compass app on my phone works just fine when standing still.
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OK. I've got the Formotion magnetic compass mounted, calibrated, and working well. Here is my report. [Edited for length.]
The first photo shows details of the physical mounting.
(http://i127.photobucket.com/albums/p135/motocomo/IMG_20160607_160920730_HDR.jpg)
On the bottom of the compass I found a 9mm diameter brass post, tapped for a 4mm x 0.7mm screw. I used the black, aluminum handlebar mount from my recent clock purchase by drilling its existing 8mm hole to 9mm, but only half way through (lower right). I had to buy a longer screw (25mm) for the clamp-to-compass connection, but otherwise it is great, and saved the $20 that Formotion gets for their mount. (The clock with its mount was about $13, I recall.) Also visible in the picture is a little non-magnetic adjusting screwdriver I made from a dowel and brass sheet to replace the execrable and flexible aluminum version that came with the compass (seen below it).
The second photo shows the final mounting position of the calibrated compass.
(http://i127.photobucket.com/albums/p135/motocomo/IMG_20160607_202253840.jpg)
Location and calibration At first I mounted the compass on the handlebar up against the clutch lever, figuring that would put it away from the "great lump of steel" I perceived near the instruments. But it was impossible to calibrate the compass -- it would only point South.
So I used my free Android gauss meter app (https://play.google.com/store/apps/details?id=com.keuwl.gaussmeter&hl=en (https://play.google.com/store/apps/details?id=com.keuwl.gaussmeter&hl=en)) and took measurements. First, I measured the field strength in the middle of my yard and found it was less than 0.5 gauss, the value that the Wikipedia article indicated applies for 50 degrees N latitude. (I'm at 43 degrees.)
Then I measured the field strength at my original mounting point near the clutch lever -- over 3.0 gauss. But another spot on the handlebar, right beside the handlebar mounting bolts, measured only about 0.4 gauss. I put the compass there and found I could easily calibrate it. (I had the motor running.)
The compensating magnets in this compass can overcome a modest field strength from the bike, but not one that is far in excess of the 0.5 gauss that the Earth is providing at its surface. I think using a gauss meter app might be a good way in general to position compasses on motorcycles. I was surprised to find such large variations in field strength at different points along the handlebar.
Performance I was able to calibrate the compass within two tick marks of each of the cardinal points (N E S W). This is within 10 degrees, good enough. I took a trip this afternoon and was very pleased -- using the sun and maps as my reference, I could see that the calibration held up on the road. The compass wanders over its heading while underway, but it settles pretty quickly so that it is not hard to interpret.
Quality of the instrument I took off the chromed brass case, hoping to see the "solid brass and stainless-steel construction for years of use" claimed on the website. The guts of the compass are made of plastic, though it seems well enough constructed. No doubt the manufacturer only meant to claim that what brass and stainless steel is present exists in the solid, rather than the liquid or gaseous states, and in that claim I can find no fault at all.
All in all I'm very satisfied. Thanks again for the recommendation, Kirby.
Moto
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Nice trick using your phone Moto! I had no idea there was an ap for that.. :smiley:
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Well done Moto. You seem to have sorted it well. It looks good there as well. For some reason I had imagined a much larger item.
Interesting clock you have there. What is it?
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Tasteful looking instrumentation.
I think it would be hard to adjust that compass. You would need a type that is adjustable not only for variation but also deviation. Then you'd have to complete a compass swing procedure similar to how they do it in aircraft and I assume ships. Not particularly difficult as far as I understand. Maybe you could find a suitable old aircraft compass with the required scissor magnets.
Or this;)
(http://content.luxurybazaar.com/images/items/PANERAI_PAM00191_1.jpg)
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Well done Moto. You seem to have sorted it well. It looks good there as well. For some reason I had imagined a much larger item.
Interesting clock you have there. What is it?
Thanks, John. I had thought it was a bit bigger myself.
That's the clock I mentioned two or three weeks ago. Here it is: http://wildguzzi.com/forum/index.php?topic=83112.0 (http://wildguzzi.com/forum/index.php?topic=83112.0). Whoops, that's six weeks ago at least! (Its handlebar mount is the one I used for the compass.)
John (Moto)
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Tasteful looking instrumentation.
I think it would be hard to adjust that compass. You would need a type that is adjustable not only for variation but also deviation. Then you'd have to complete a compass swing procedure similar to how they do it in aircraft and I assume ships. Not particularly difficult as far as I understand. Maybe you could find a suitable old aircraft compass with the required scissor magnets.
/content.luxurybazaar.com/images/items/PANERAI_PAM00191_1.jpg[/img]
Thanks for the "tasteful" comment.
The compass is easily adjustable for variation, and suitable for the compass swing procedure that I've just been reading about. In fact, because of Kirby's earlier mention of having calibrated his compass (the same model) on an airport compass rose, I have located a recently-painted one at a small, unattended airport near me (Palmyra, WI) and plan to head there tomorrow or the next day for a swing:
(http://wisconsin99s.org/public_html/images/palmyra%20rose.jpg)
As for deviation, I understand that is usually accounted for with a compass deviation card, which records what course to steer for a true heading of 0, 30, 60, ..., 330 degrees. The idea, as you know, is that the necessary correction can change for different courses.
I had been thinking about that issue too after reading up, and decided that a regular compass deviation card -- the kind I just described -- would be inappropriate for highway travel, since I can't choose my steering direction freely on a highway. But there is nothing to stop me from making at least an approximate "reverse" card, which would indicate my true heading for the indicated points 0, 30, 60, ... degrees on the compass. Since I'll be using the compass rose to try to a better job on the basic variation adjustment, I'll probably go ahead and make such a deviation card unless I get tired of repositioning my bike, or get chased away. Of course, there is probably little real value in doing this, and I have no expectation of posting this card below my compass as is done in aircraft. Enough is enough!
Moto
P.S. I don't know what a scissor magnet is, but would be interested to learn. The compass contains pairs of magnets on rotating shafts.
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Compasses read magnetic north.
Charts are drawn in true north.
Aviation charts show the difference between magnetic and true north for a given area.
This is variance. You correct for variance when navigating from an aviation sectional chart.
Compasses are not perfect.
The errors are noted on a deviation card after the compass is swung.
You use the deviation numbers to select a compass reading that will fly you on the magnetic heading you calculated from your charts.
That being said I have the Formotion compass on the EV I bought last year. It pointed north all the way from Massachusetts to Tennessee and back last month. Sounds like a few people have had good luck calibrating it. I'll probably give it a shot. Compasses are a fun way to explore. Used one on the bicycle. Would ride west 3 hours, south 3 hours, east 3 hours then north 3 hours and see how close I ended up to home base. Do the same on the bike but just using the sun. Clouds and noon are always there to keep it interesting
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Judging from some of those Kansas roads, you're putting more thought into the direction of travel than they put into the direction of build. Have you noticed how they go straight for 120 miles and suddenly do a 90º right for a few yards and then another 90º left? It's like they started building from both ends toward the middle but nobody calibrated their compass. Left to their natural inclinations they would have bypassed.
If you were prepared to settle for a gps 'compass' that only resolves to cardinal points, and if your intent is to know which road at the intersection trends in what direction, what's the fuss about calibration? If the road trends south, does it matter if it's 175º or 185º?
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Thanks for the "tasteful" comment.
The compass is easily adjustable for variation, and suitable for the compass swing procedure that I've just been reading about. In fact, because of Kirby's earlier mention of having calibrated his compass (the same model) on an airport compass rose, I have located a recently-painted one at a small, unattended airport near me (Palmyra, WI) and plan to head there tomorrow or the next day for a swing:
(http://wisconsin99s.org/public_html/images/palmyra%20rose.jpg)
As for deviation, I understand that is usually accounted for with a compass deviation card, which records what course to steer for a true heading of 0, 30, 60, ..., 330 degrees. The idea, as you know, is that the necessary correction can change for different courses.
I had been thinking about that issue too after reading up, and decided that a regular compass deviation card -- the kind I just described -- would be inappropriate for highway travel, since I can't choose my steering direction freely on a highway. But there is nothing to stop me from making at least an approximate "reverse" card, which would indicate my true heading for the indicated points 0, 30, 60, ... degrees on the compass. Since I'll be using the compass rose to try to a better job on the basic variation adjustment, I'll probably go ahead and make such a deviation card unless I get tired of repositioning my bike, or get chased away. Of course, there is probably little real value in doing this, and I have no expectation of posting this card below my compass as is done in aircraft. Enough is enough!
Moto
P.S. I don't know what a scissor magnet is, but would be interested to learn. The compass contains pairs of magnets on rotating shafts.
You say your compass is accurate to within 10 degrees which seems acceptable and a pretty good result considering the amount of metal and a nearby instrument cluster. This is just Gee-wiz banter.
Compass variation is simply the difference between true north and magnetic north in your locale. As you move away from your theater you will have to apply a variation correction factor in addition to the local calibration. Of course this is pointless on a motorcycle where you won't be too concerned about a few degrees.
Deviation is the compass error imposed by the local magnetic fields created by the vessel and the compass itself. Unlike variation this error isn't constant (i.e. add 8 degrees). Since the needles alignment with nearby magnetic fields change deviation varies with the direction of the vessel. Compasses that allow for deviation typically contain sets of magnets (scissor magnets) that allow for adjustment in more than one azimuth section. The compass is adjusted through the compass swing procedure and the remaining difference is applied to a correction chart. I saw the effect of this on a sailing trip where I bought a pair of used large speakers and stowed them under the cockpit. It made a noticeable difference!
Your post inspired me to get a portable compass myself. I decided to get a strap compass since I intend on combining my riding with hiking.
http://www.glensoutdoors.com/silva-wrist-band-compass.html?gclid=CjwKEAjwp-S6BRDj4Z7z2IWUhG8SJAAbqbF3e8Tusm700pNyPnEsAxNHek0Q_Ov1cwjWnn1C-CkIDhoCzYzw_wcB
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...
That being said I have the Formotion compass on the EV I bought last year. It pointed north all the way from Massachusetts to Tennessee and back last month. Sounds like a few people have had good luck calibrating it. I'll probably give it a shot.
A couple of other ideas for you if you have any trouble calibrating this time (aside from my gauss meter recommendation). Renthal makes some nice looking and apparently high quality aluminum streetbike handlebars in a few different bends, available on Amazon for about $54. I considered getting a set at first. I found this post from a bicyclist who reported no luck with a handlebar compass on his "all steel" bike and complete satisfaction with the same compass on his bike with aluminum handlebars: http://forum.cyclinguk.org/viewtopic.php?t=61710 (http://forum.cyclinguk.org/viewtopic.php?t=61710).
On the advice of more than one previous poster, I considered degaussing. I can report that waving the back of my 120w soldering gun around the problem area had no apparent effect. Reading up on the topic, I concluded that more amperage would be needed, and that successful degaussing might be a bit more involved than I had hoped.
Moto
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Judging from some of those Kansas roads, you're putting more thought into the direction of travel than they put into the direction of build.
I ride mostly here in western Wisconsin, with lots of twisty and confusing roads. Not Kansas.
If you were prepared to settle for a gps 'compass' that only resolves to cardinal points, and if your intent is to know which road at the intersection trends in what direction, what's the fuss about calibration? If the road trends south, does it matter if it's 175� or 185�?
I already said I'm happy with my +/- 10 degree calibration. The visit to the airport compass rose is just for fun.
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Your post inspired me to get a portable compass myself. I decided to get a strap compass since I intend on combining my riding with hiking.
http://www.glensoutdoors.com/silva-wrist-band-compass.html?gclid=CjwKEAjwp-S6BRDj4Z7z2IWUhG8SJAAbqbF3e8Tusm700pNyPnEsAxNHek0Q_Ov1cwjWnn1C-CkIDhoCzYzw_wcB
That's a good=looking compass, and it could save your life someday. Did you read about the 66-year old hiker who stepped away from the Appalachian Trail recently, got lost, and died after 20-some days?...
You can never have too many compasses. Maybe I need a Silva watch strap compass too.
EDIT: The hiker's name was Geraldine Largay. The official report of the investigating officer does show a photograph of a small compass she carried: https://assets.documentcloud.org/documents/2842887/Geraldine-Largay-Report-Exerpt.pdf (https://assets.documentcloud.org/documents/2842887/Geraldine-Largay-Report-Exerpt.pdf). (The last photo, at the end of the report.) Her fatal mistake, it seems, was seeking higher ground for a good cell phone signal, instead of heading downhill for a road or stream.
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That's a good=looking compass, and it could save your life someday. Did you read about the 66-year old hiker who stepped away from the Appalachian Trail recently, got lost, and died after 20-some days?...
You can never have too many compasses. Maybe I need a Silva watch strap compass too.
I haven't but it makes me feel like it was $10 well spent. That is where I'm going in august.
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That looks really nice.
Did I miss where you posted the model number of the compass you purchased?
I'm not sure of the number. Here's a link. It's on closeout, sale priced at $50 plus shipping. Not cheap. However, it's the best compensated compass I know of for a motorcycle right now. (Marlinsclocks.net offers a different one, but it's really a marine compass, complete with calibration instructions for a boat!)
All of Formotion's products are being withdrawn from retail sale. So, love em or hate em, this seems to be the last chance to get em.
Moto
http://www.formotionproducts.com/shop-1/black-compass (http://www.formotionproducts.com/shop-1/black-compass)
EDIT: I forgot to mention another, larger Formotion compass, on sale for only $15! Too large for me, I decided, but a good value:
http://www.formotionproducts.com/shop-1/compass-white (http://www.formotionproducts.com/shop-1/compass-white)
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Frankly I'm a little amazed that the compass is accurate to +/- 10 degrees in that setting and I'm sure that will be good enough for your purposes. Hell, if you are hand steering a yacht to a (properly swung and adjusted) compass course and you can keep within +/- 5 degrees you are doing very well indeed!
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Frankly I'm a little amazed that the compass is accurate to +/- 10 degrees in that setting and I'm sure that will be good enough for your purposes. Hell, if you are hand steering a yacht to a (properly swung and adjusted) compass course and you can keep within +/- 5 degrees you are doing very well indeed!
Well, +/- 10 degrees was my rather quick judgement after calibrating in a parking lot using a hand compass reference. I'm sure the headings were within two tick marks (10 degress) of the nominal directions on the four cardinal points. But I'm not so sure the motorcycle was positioned accurately enough to make those observations worthwhile. I'll report back on my results on the airport compass rose. They may not be so good!
I'm uncertain how best to position the motorcycle on the compass rose. Suggestions welcome.
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I did ride down to the airport compass rose at Palmyra, WI, to recalibrate my new compass today.
The short report is:
True Compass Compass
Heading Bearing Deviation
N 0 10 +10
E 90 90 0
S 180 193 +13
W 270 275 +5
Not quite as good as my initial report of +/- ten degrees, but close.
I did the full compass swing, as I understand it:
1. Point bike N, adjust compass to read 0 degrees
2. Point E, adjust it to read 90
3. Point S, remove half of any difference from 180
4. Point W, remove half of any difference from 270.
5. Cycle through the 12 available points of the compass rose (0 30 60 90 ...) and record the readings.
Here is the record from step 5:
true compass deviat
0 10 10
30 43 13
60 55 -5
90 90 0
120 118 -2
150 160 10
180 193 13
210 211 1
240 243 3
270 275 5
300 290 -10
330 325 -5
The deviations now seem to be all over the map. Taking all the variability into account (with some interpolation*), I selected these as my working compass corrections:
Compass
bearing correction
N (0) -5
E (90) 0
S (180) -10
W (270) 0
Moto
*I interpolated by eye from this smoothed fit:
(http://i127.photobucket.com/albums/p135/motocomo/smoothed_compass_data_1.png)
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Update: I found my compass calibration was not as good as I reported once I started riding around, so I'm updating this thread.
At 50 mph the compass bearing could be off by up to around 45 degrees from the value I obtained with the bike stationary at the airport compass rose. I could tell this when I was on true N/S or E/W roads. I tried disconnecting the speedometer cable in case the spinning magnets inside were the problem, but no luck.
So I decided to calibrate to the readings I got at 40-50 mph on N/S and E/W roads, working from an intersection where two such roads met. I got the bearings to within about 15 degrees on all four cardinal points, while under way, though this threw off the stationary readings.
Of course using N/S and E/W roads requires some thought about the difference between geographic and magnetic north, but in my area the two are only 2 degrees apart, so it didn't matter much.
Moto
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How about the magnetometer-driven digital compass in my Android phone? Is it more or less accurate than a whiskey compass?
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How about the magnetometer-driven digital compass in my Android phone? Is it more or less accurate than a whiskey compass?
An Android phone's magnetometer-based compass is just an uncompensated magnetic compass, and should work fine away from the bike.
I think "whiskey compass" refers to the compensated type of magnetic compass installed on an airplane (which is fluid-filled, sometimes with alcohol, maybe explaining the name). If so, the Formotion compass is a simple whiskey compass.
Your phone's compass would be a good standard for navigation if you got off the bike, better than the compensated Formation compass. But you would need to know your magnetic declination (or variance) to use it to find true geographic headings. You can find magnetic declination maps by googling.
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The compass function in my gps app allows me to switch between magnetic and true readings. This implies that it refers current position to a declination map and corrects accordingly.
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The compass function in my gps app allows me to switch between magnetic and true readings. This implies that it refers current position to a declination map and corrects accordingly.
Yes, as I understand it, the reading is magnetic and is corrected by referring to your location, via GPS and a declination map. However (of course), it can still be thrown off by nearby magnetic fields, meaning the corrected reading will be wrong too.
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Those with newer bikes might like to know the same Formotion compass works just about as well on my Griso, being accurate to within about 15 degrees at each cardinal point. The same clock mount also works to hold the compass, needing a 35mm screw this time. (But this time you can see a lot of the screw extending below the compass, in the picture.) The magnetic field at the mounting point measured about 0.5 Gauss this time, similar to the successful mounting point for the T3.
(http://i127.photobucket.com/albums/p135/motocomo/IMG_20160903_205607162.jpg)
I just ordered a second compass. A cheap thrill compared to some others I could name.