Digital Compass
For recreational orienteering, or survival, all you need is an inexpensive analog compass. For sea navigation, and for trail making, surveying, wildlife monitoring, or anything else where consistently exactitude is require, this scope is probably what you want. Waterproofed, and illuminated at night with fiber optics, these compasses can supplement GPS finders.
-- KK
Traditional compass designs for hikers are unreliable and hard to use. A magnetized needle wobbles on a primitive bearing, and its accuracy is affected by local mineral deposits. Enhancements of this basic design are still unsatisfactory; for instance, you may find yourself peering into a hinged mirror, trying to focus simultaneously on the wobbling needle in front of you, and a distant object reflected in the mirror, upside-down.
After much searching I found that marine supply companies seem to make the most advanced compasses. I bought a KVH Datascope for about $300. It is designed as a monocular; you look through the unit, which provides 5x magnification, crosshairs, and a digital readout superimposed, accurate to +/- half a degree. This is a sighting compass, meaning that you sight a distant object in the direction in which you wish to travel, walk toward that object, taking another sighting, and so on. The fact that the compass is still accurate if you don't hold it level (it has a 20 degree tolerance) is a big plus; traditional compasses are useless unless you manage to hold them almost precisely level.
Calibration of the compass is very simple, after which you dial in the deviation of magnetic north from true north in your area. (This information is available on any topo map.) Supposedly the compass is smart enough to compensate for local deposits of ferrous metal, power lines, etc. All I know is that I was finally able to locate the small metal pegs marking the corners of my 40 acres in the middle of nowhere. A professional surveyor's compass had not enabled me to do this.
The Datascope requires three button-type batteries, and must be recalibrated each time you change the batteries, because each new set of batteries has slightly different magnetic characteristics. My first set has lasted two years so far. The compass comes in a nice padded carrying case, includes a digital clock, is supposedly "totally waterproof," and weighs 11 ounces. If you're tempted to buy one, check Froogle; I found online prices varying by as much as $150.
-- Charles Platt
KVH Datascope
Manufactured by KVH
$350
from Boater's World
Favorite (15)
Jib Halyard
The hinged mirror compasses, such as the Silva Ranger, are the most practical ones there are. It doesn't sound like the reviewer knows how to use them.
The mirror allows you to see the compass needle while viewing the objective through the V-sight at the top. Next best thing to a digital read-out, but without the hassle of batteries, etc.
If you are focusing on "a distant object reflected in the mirror, upside-down" you are definitely doing it wrong wrong wrong.
In fact, I would nominate the Silva Ranger (or better yet, the Suunto version with global gimbal) as a Cool Tool in its own right: a no-nonsense, durable and reliable piece of kit. These thave been the preferred types of compasses by most militaries around the world, and for good reason.
G. Hubler
I own a KVH Datascope and have used it as a navigation instrument on my sailboat. I agree that it is a capable instrument. The magnification is helpful when taking bearings as is the ability to record and recall multiple bearings. The latter feature is particularly useful in crossing situations to determine if you are on a collision course.
I loved this instrument for the first two years of service. It seemed well-built and robust. The only hassle was replacing batteries because of the poor design of the battery compartment.
On the downside, the warranty is only one year and problems that develop after that time likely are not repairable as, according to KVH, opening the case essentially destroys the instrument and it is cheaper to replace it than repair it. At a suggested retail price of $445, that is not something you will want to do very often. I think there is a discount replacement price for the first 3 years but, in my mind, a quality navigation instrument should last well beyond three years.
In my case, the visual field became distorted by "bubbles". KVH told me it was my fault because I must have left it in the sun. Well....I use it on a sailboat in the Pacific Ocean! I always install the lens caps when I'm not shooting bearings, but otherwise I keep it around my neck so that I can take bearings whenever I need to. When not in use I stored it in its protective case. If it can't stand sun exposure, than it isn't really designed for marine use.
So, now I use a VION Mini 2000 hand bearing compass (often called a "hockey puck". No batteries, easy to shoot bearings, always works, phosphorous chemical light source for night use, no worries. In instances where I require magnification to take an accurate bearing I use binoculars with an integral compass (Steiner).