Suunto Tandem User manual

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SUUNTO TANDEM

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Suunto, ristop Computer, Suunto Tandem and their logos are registered or
unregistered trademarks of Suunto Oy. All rights reserved.
hile we have taken great care to ensure that information contained in this
documentation is both comprehensive and accurate, no warranty of accuracy is
expressed or implied. Its content is subject to change at any time without notice.
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Suunto Tandem
USER'S GUIDE
EN

3
TABLE OF CONTENTS
SUUNTO TANDEM, TWO PRECISION INSTRUMENTS IN ONE ....................4
ADJUSTING OPTICS .........................................................................................4
CLEANING THE TANDEM .................................................................................5
CONTACT MEASURING ...................................................................................6
BEARING COMPASS ........................................................................................7
COPYRIGHT, TRADEMARK AND PATENT NOTICE .....................................11
ISO 9001 ..........................................................................................................11
CLINOMETER ..................................................................................................11

4
SUUNTO TANDEM, TWO PRECISION INSTRUMENTS IN ONE
Congratulations on your choice of the Suunto Tandem. The Suunto Tandem is all you
need for both slope/height measurements and compass bearings. It is a liquid-filled
precision compass and clinometer in one compact aluminum housing that is easy to
use and rugged enough to protect against impact, corrosion, and water. This top-
quality precision instrument combines precision accuracy with fast and easy one-
hand operation.
The pocket-size construction renders the Suunto Tandem most suitable for every type
of work. Its unique shape makes it comfortable to hold in your hand. The optics of the
Tandem can be adjusted to make the reading easier. The clinometer scale is in
degree and percent (0 – 90°, 0 – 150 %) while the compass scale is azimuth (0 –
360° with reverse scale). Both the clinometer and compass are graduated in 1° / 1 %
increments and each is individually calibrated. The two edges at 90 degrees angle
make the contact measurements possible, for example, when installing and
positioning a satellite antenna.
ADJUSTING OPTICS
The optics of the Tandem can be adjusted by turning the eye
piece with your fingers as shown in Figure 1. Adjust the eye
piece so that both the hairline and the scale are sharp and the
eye piece slot settles in a vertical position in the bearing
compass and in a horizontal position in the clinometer.
Fig. 1. Adjusting optics

5
CLEANING THE TANDEM
In the case humidity or dirt develop inside
the Tandem it can be cleaned by removing
the detachable eye piece. The eye piece can
be removed by rotating it counter-clockwise
(Fig. 2). Rinse with clean water, allow to dry
and carefully reassemble the eye piece.
Caution! Do not use detergents or solvents
of any kind as they might cause damage to
the capsules.
0
90
90
Code:
PM-5/360PC
TANDEM
W
E
N
S
Fig. 2. Removing the eye piece

6
CONTACT MEASURING
The Tandem can be used for aligning satellite
dish antennas or for other type of contact mea-
suring. The clinometer incorporates two different
contact edges (see Fig. 3) which enable the mea-
surement to be made compared to the horizontal
or vertical plane. The scale (0 – 90 – 0 degrees)
can be used in contact measuring and it gives the
angle of the surface compared to the contact
plane.
TWO CONTACT
EDGES
0
90
90
Code:
PM-5/360PC
TANDEM
W
E
N
S
Fig. 3. Edges for contact
measurement

7
BEARING COMPASS
Construction
The bearing compass is designed to combine extreme accuracy with ease and speed
of operation. The card is supported by a jewel bearing and it is immersed in a
dampening fluid, giving vibrationless, smooth movement. The compass has been
given permanent antistatic treatment.
Inclination - balancing
The compass card is balanced to correspond to area within which the compass is
used. When using the compass elsewhere (e.g. on trips abroad) the change of the
vertical magnetic field could make the compass card dip and this may cause
difficulties in taking the bearing. The balancing zone (see Fig. 4), if other than one, is
indicated on the back of the instrument below the serial number, contact your dealer
for details.
2
1
4
3
5
Fig. 4. The balancing
zones

8
Declination
The compass reads magnetic north, which differs from true north by the amount of
the local declination which is printed on your map. In order to lay out on a map a
bearing obtained with the compass, the plus or minus declination for the locality in
question must be added to or subtracted from the compass bearing.
Deviation
Iron and steel objects close to the compass, like a wristwatch or steel rimmed
eyeglasses, may cause deviation. Whenever possible, remove such objects to a safe
distance. Large structures like buildings, reinforced concrete quays etc. will cause
deviation at some distance. A reverse sighting from the opposite end of the target line
will show up any deviation present.
Operation
With both eyes open, aim the compass so that the hairline is superimposed on the
target, when viewed through the lens. The main scale (large numbers) gives the
bearing from your position to the target, the small numbers give a reverse bearing
from the target to your position. This feature is of great assistance when calculating a
precise position.
Use the left or the right eye as preferred. With both eyes open, an optical illusion
makes the hairline appear to continue above the instrument frame, superimposed on
the target. This improves reading accuracy and speed.

9
Because of an eye condition called heterophoria,
the reading accuracy of some users may be
impaired. Check for this as follows:
Take a reading with both eyes open and then close
the free eye. If the reading does not change
appreciably there is no disalignment of the eye
axes, and both eyes can be kept open. Should there
be a difference in the readings, keep the other eye
closed and sight halfway above the instrument
body. The hairline now rises above the instrument
body and is seen against the target (Fig. 5).
0
90
90
Code:
PM-5/360PC
TANDEM
W
E
N
S
0350
10
190 180 180
View
Fig. 5. The hairline is seen against the target

10
The instrument can also be
used for triangulation, see Fig 6.
The bearings obtained from the
main scale are 0° against the hill
and 64° against the curve of the
road, or 180° and 244° on the
reverse scale. Your own location
is indicated by the intersection
point of these two lines. When
performing very accurate posi-
tioning tasks the bearings
obtained have to be corrected
for local declination.
The co-tangent table at the back
of the Tandem can be utilized
for distance calculations, and
especially for locating position in
cases where two landmarks are
visible at a narrow angle. This
procedure is also illustrated in
Fig. 6.
The angle between the curve of the road and the oil derrick is 15°. A line is drawn at a
90° angle to the 64° bearing line from the curve of the road toward the oil derrick
bearing line. The distance, as measured on the chart, is 1.6 km [1 mile]. Then your
position is cot 15° x 1.6 km = 6 km [cot 15'° x 1 mile = 3.7 mile] along the corrected
bearing line of 64°.
t
0°64°15°90°
Fig. 6. Triangulation

11
COPYRIGHT, TRADEMARK AND PATENT NOTICE
These instructions are copyrighted and all rights are reserved. It may not, in whole or
in part be copied, photocopied, reproduced, translated, or reduced to any media
without prior written consent from SUUNTO.
SUUNTO, Tandem and their logos are all registered trademarks of SUUNTO. All
rights are reserved. Patents have been issued or applied for one or several features
of this product.
ISO 9001
SUUNTO 0y's Quality Assurance System is certified by Det Norske Veritas to be
according to the ISO 9001 in all SUUNTO Oy's operations (Quality Certificate No. 96-
HEL- AQ-220).
CLINOMETER
Construction
The scale card is supported by a jewel bearing assembly and all moving parts are
immersed in a damping liquid inside a high strength hermetically sealed plastic
container. The liquid dampens all undue scale vibrations and permits a smooth
shockless movement of the scale card.

12
Instructions for use
Readings are usually taken with the right eye. Owing to differences in the keenness of
the sight of the eyes and because of personal preferences the use of the left eye is
sometimes easier. It is of prime importance that both eyes are kept open. The sup-
porting hand must not obstruct the vision of the other eye.
The instrument is held in front of the reading eye so
that the scale can be read through the eye piece,
and the round side-window faces to the left.
The instrument is aimed at the object by raising or
lowering it until the horizontal hairline is sighted
against the point to be measured. The position of
the hairline now on the scale is the reading. Owing
to an optical illusion the hairline (cross-hair) seems
to continue outside the housing and is thus easily
observed against the sighted object (Fig. 7).
The left-hand scale angle gives the slope angle in
degrees from the horizontal plane at eye level.
The right-hand scale gives the height of the point of
sight from the same horizontal eye level, and it is
expressed in per cent of the horizontal distance.
The following example illustrates the procedure.
+ AND -
DEGREE
SCALE
+ AND -
PER CENT
SCALE
HAIRLINE
EXTENDED
BY OPTICAL
ILLUSION
THIRD SCALE
IN SIDE
WINDOW
10
10
-
0
0
-
10
10
+
+
10
10
-
0
0
-
10
10
+
+
Fig. 7. The hairline
indicates the reading

13
The task is to measure the
height of a pillar at a distance
of 25 m [82 ft] on level ground
(Fig. 8).
The instrument is tilted so that
the hairline is seen against the
pillar-top (apex). The reading
obtained will be 48 % (ca
25 ½°), As the distance is
25 m [82 ft] the height of the
pillar is 48 / 100 x 25 = ca.
12 m [48 / 100 x 82 ft = ca.
39 ft]. To this must be added
the eye's height from the
ground, e.g., 1.6 m [5 ½ ft].
Their sum is 13.6 m [44 ½ ft],
the height of the pillar.
In very exact measurements,
and particularly on sloping
ground two readings are
taken, one to the top, the other
to the base of the pillar. When
the pillar base is below eye
level the percentages ob-
tained are added. The total
height is the sum percentage
25 m [82 ft]
12 m
[38 ft]
1.6 m
[5½ ft]
48 %
25 ½°
25 m [82 ft]
3.25 m
[10½ ft]
41%
10.25 m
[33½ ft]
13.5 m
[44½ ft]
13%
Fig. 8. Measuring height of a pillar
Fig. 9. Taking two readings

14
of the horizontal distance. For example (Fig. 9), if the apex reading is 41 % and the
ground reading 13 %, the total height of the pillar measured from a distance of 25 m
[82 ft] is (41 + 13) / 100 x 25 m = 54 / 100 x 25 m = ca. 13.5 m [(41 + 13)/100 x 82 ft =
54/100 x 82 ft = ca. 44 ½ ft].
When the pillar base is above eye level, the base reading is subtracted from the apex
reading, and the total height is the difference percentage of the horizontal distance.
For example (Fig. 10), if the apex reading is 64 % and the base reading 14 %, the
total height is (64 – 14) / 100 x 25 m = 50 / 100 x 25 m = 12.5 m [(64 – 14) / 100 x 82 ft
= 50 / 100 x 82 ft = 41 ft]. When calculations are made mentally, it is advisable to use
measuring distances of 50, 100 or 200 ft, for the sake of simplicity.
Fig. 10. Pillar above eye level
3.5 m
[11½ ft]
64%
12.5 m
[33½ ft]
14%
25 m [82 ft]

15
All readings on the percentage scale are based on the horizontal distance. This
means that if the distance on sloping terrain is measured along the ground an error is
introduced, and this must be corrected for accurate results. The error is insignificant
for most purposes at small ground slope angles but increases progressively as the
angle increases.
The trigonometrical correlation is H = h x cos a
where
H = the true or corrected height,
h = the observed height and
a = the ground slope angle.
With the aid of the above equation the correction can also be made in the distance,
where
h = the distance measured along the ground
H = the horizontal distance sought. If the corrected distance is used no correction in
the height observed is needed.

16
When calculating the hori-
zontal distance by using
the ground distance and
the slope angle, it must be
pointed out that an error is
introduced if the slope is
measured from eye level to
the pillar base. Measuring
the slope along the ground
would be cumbersome and
inconvenient. No error is
introduced, however, when
the slope angle is mea-
sured from eye level to a
sighting mark made or
placed on the pillar at eye level (Fig. 11) whereby the two lines of measurement
become parallel. The true angle of slope is 9 degrees. The example shown in Fig. 11
illustrates both methods of calculation.
Method 1. Measure the ground distance. This is found to be 25 m [82 ft]. Then
measure the slope angle. This is 9 degrees. Read percentages of top and ground
points. These are 29 and 23 per cent.
Calculate:
1.6 m
[5½ ft]
29%
1.6 m
[5½ ft]
9%
25 m
[82 ft]
23%
24.7 m [81 ft]
Fig. 11. Calculating horizontal distance by using
ground distance and slope angle
23
100
---------29
100
---------52
100
---------
=+

17
Take 52 per cent of 25 m [82 ft]. This is 13 m [42.6 ft]. Multiply this by the cosine of
9 degrees.
0.987 x 13 m = 12.8 m [0.987 x 42.6 fl = 42 ft]
Method 2. Multiply the ground distance by the slope angle cosine (strait distance).
0.987 x 25 m = 24.7 m [0.987 x 82 ft = 80.9 ft]. Add percentage readings as above
and take the sum percentage of the corrected distance. 52 / 100 x 24.7 m = 12.8 m
[52 / 100 x 80.9 ft = 42 ft]. This example shows that a slope angle of 9 degrees
causes a correction of only 2.3 % but when the slope angle is 35 degrees the
correction means a reduction of about 18 % in the observed height.
Nomographic height correction
When the accompanying nomogram is used, all correction calculations become
unnecessary. Only a ruler or some other convenient object with a straight edge is
needed to obtain the nomographical solution. The nomogram is used by placing the
ruler so that its edge intersects the angle scale on the left at the slope angle point and
the observed height scale (on the right) at the pertinent point. The corrected height (or
distance) is read at the point where the edge intersects the corrected height scale in
the middle. When using a measuring distance of 20 m or 100 ft along the ground the
correction procedure becomes very simple. No slope angle measurement is then
necessary. One needs only the reading of the top point and that of the ground point.
Depending on the situation their sum or difference gives the apparent height directly
in feet. This is then corrected as follows:

18
First, find on the right-hand scale in the
nomogram the point indicating the
apparent height. Secondly find on the left-
hand double scale the point indicating the
ground point reading. Thirdly, connect
these points. The corrected reading will
be found from the pertinent middle scale
at the point of intersection. In this
procedure the slope angle can be
neglected as the left-hand ground point
scale has been constructed so that both
the ground slope angle and the average
eye level height of 1.6 m [5.5 ft] have
been taken into account.
Uphill
Base reading
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
2
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
m
Apparent height
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
m
Corrected height
L-20
m
Downhill
Fig. 12.

Suunto Tandem
GUIDE DE L'UTILISATEUR FR