Brunton 7DNL Compass Review

Small, light, easy to use, and about the right size for a simple baseplate model.

Recommended

Overall Rating: Recommended

Small, light, easy to use, and about the right size, but skip the supplied cord neck loop.

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by Roger Caffin |

Overview

Brunton 7DNL Compass Review - 1
Brunton 7DNL compass, courtesy Brunton.

There are many different sorts of compasses, ranging from tiny button things to great hulking surveyor/military things. In between we have the typical baseplate compasses.

One problem with the tiny compasses is that many of them are prone to sticking if you don't have them precisely level. I've tried quite a few and never been really confident about relying on them, even though they are so ultralight. Another problem with them is that they don't allow you to get a very accurate bearing. In fact, many of them don't have much more than the four (or eight) cardinal points marked on them.

The obvious problem with the big surveyor/military ones is weight. I have an Australian Army prismatic compass which weighs half a ton: it is made from solid brass. It (truthfully) comes from World War II. To be sure, I can read it (and trust it) to half a degree or better, but I don't need that accuracy in the field. I did find it useful for surveying my farm though.

In between we have the broad category of baseplate compasses. These have a disk-shaped liquid-filled module mounted on some sort of flat baseplate and come in a range of weights and sizes. The heavy end is the domain of the mirror and other sighting compasses. I am sure they have a use somewhere, but I find them rather clumsy and impractical. In fact, some of them seem downright awkward or worse. I also find that I can get just as good a bearing from a simpler compass as one of these, so they are just excess weight for me. Perhaps if I was trying to locate myself on a broad flat plain by sighting on distant sharp peaks they might have a slight advantage, but 'flat plains and distant peaks' doesn't describe any of the country I walk in.

That leaves us with the simple baseplate units. Some of these have big baseplates, and others have little baseplates. The argument for the bigger baseplate is greater accuracy, except that I have never found that necessary or even useful, even for tricky navigation. The bigger baseplates also sometimes have a magnifying glass embedded in them: I haven't found that to be a real lot of use either.

Brunton 7DNL Compass Review - 2
Brunton 9030 compass, courtesy Brunton.

In fact, up until recently my favourite 'baseplate' compass did not even have an extended baseplate per se. It was very much like the Brunton 9030 shown here: just the round compass module, rotating inside an outer ring for declination adjustment. Yes, there is a 'baseplate' attached to the black ring under the rotating module, with the logo and arrow on it. I bought mine in France after I (ahem) lost my previous compass in the mountains. I think mine was made in China: it was fairly cheap. I have shown the Brunton 9030 here to illustrate what I mean by a compass without an extended baseplate. But after many long trips in the mountains over many years, my Chinese one started to lose the damping fluid inside the module, and it was time for a new one.

I looked at a range of baseplate compasses. Many of them had long plates with corners. The length can be a bit inconvenient at times, since I usually carry my compass hanging around my neck (a compass is of no use if you can't get at it easily). The corners on the long baseplates can dig into my chest. This model 7DNL is the lightest and smallest baseplate in the Brunton range, at only 25.5 g (0.91 oz).

The rotation of the compass module on the baseplate to set the local declination is really very smooth, but there is just enough friction to keep the declination set. The red ring used to rotate the module is a smooth and tactile polymer band: no sharp corners. It handles nicely.

The markings around the edge have been hot-stamped into the plastic: they are not just painted on the surface. This means it should be a long while before they wear off. One could wish the lines were a shade narrower, but really they don't matter that much. I normally align the compass with the needle anyhow by rotating the whole unit. This automatically corrects for the local declination.

Brunton 7DNL Compass Review - 3
North is THERE??

One thing I did notice was that the needle looks a bit tilted when the compass is flat on the table. The white S-seeking end of the needle points slightly downwards. That means I have to tilt the compass slightly (about 5 degrees) to be absolutely sure the needle is able to swing freely. This isn't hard to do and becomes automatic.

The need for this tilt is hardly surprising, as the magnetic field around where I live (Sydney, Australia) is actually tilted some 64 degrees downwards. That's really pretty savage, so a tilt of the compass needle of 5 degrees is rather small. Actually, all our compasses need a similar amount of tilt to swing most freely, so there is nothing special about this one. Yes, in Europe the tilt goes the other way, as expected.

Brunton supplies a soft red loop of cord which can be used as a neck loop for hanging the compass around your neck. It's a very good idea, and that's how I carry my compass. However, an hour after hanging the compass around my neck, I found the cord was really twisted up something awful. I unraveled all the twists and continued. An hour later, the twists were back: this happened several times in one day. I simply do not know what was the matter with the string, but it was too much for me and I replaced it with my own.

Specifications and Features

BrandBrunton
ManufacturerSilva Production (looks identical to Silva Field 7)
Country of originSweden
Model7DNL
MaterialVarious plastics
Needle pivotSapphire jewel bearing
Graduations2 degrees, hot stamped
Declination ScaleIntegral
Measurement ScalesMetric and Imperial
Size85 x 54 x 9.5 mm (3.4 x 2.1 x 0.37 in)
Weight (claimed)25.5 g (0.9 oz)
Weight (measured)27 g (0.95 oz) with supplied neck cord
MSRPUS$15, but retail US$10 - 12 has been seen

What’s Good

  • Robust
  • Light
  • Easy to use
  • Bold markings

Possible Improvements

  • Slightly finer definition on the printing
  • Better quality string
Disclosure: The vendor provided this product to the author and/or Backpacking Light at no charge, and it is owned by the author/BPL. The author/Backpacking Light has no obligation to review this product to the vendor under the terms of this agreement.

Citation

"Brunton 7DNL Compass Review," by Roger Caffin. BackpackingLight.com (ISSN 1537-0364).
http://backpackinglight.com/cgi-bin/backpackinglight/brunton_7dnl_compass_review.html, 2010-05-25 00:00:00-06.

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Brunton 7DNL Compass Review
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Daniel Goldenberg
(dag4643)

Locale: Pacific Northwet
Re: Re: Re: re Adjustable declination on 06/10/2010 08:52:49 MDT Print View

"If you choose to do this it might be good to do it with an eraseable pencil, otherwise you'll end up with either a lot of lines on your map or an inaccurate declination over time. Magnetic declination is not static. It changes from year to year."

True that magnetic deviation is not static but I wear out a map long before there's a need to change any magnetic north gridlines. :)

Paul Davis
(pdavis) - M

Locale: Yukon, 60N 135W
Grid North, True North, Declination, UTM Grid on all topos in Canada on 06/13/2010 19:01:50 MDT Print View

All: I should have pointed out that we like compasses with built-in declination, as all Canadian topo maps are printed with a 1000 Metre Universal Transverse Mercator Grid, and a handy arc showing how far off this is from Magnetic North, and True North.

So, no pencil lines in Canada! Use the UTM grid! Mind you, the place was only completely mapped in the mid 1980's, and many of our 'maps' North of 60 are 'photo maps', meaning top-line versions of aerial photos from the 1940's!As well, nothing more detailled than 1:50,000 for the Can. national topo system (a few mine areas=1:25,000!)---I envy European and orienteering maps at 1:10,000!

Always having UTM grid available on a map means pretty much always using the Silva 1,2,3 system to get around.

You do need to note which UTM Zone you are in, as the UTM grid numbers do repeat---we use Lat. + Long. for setting up stuff with aviators...

I used the Suunto today for an insurance bearing when coming down from above treeline via a braided horse-foot-ATV series of trails, worked like a charm. Didn't even have to stop walking!