sretaw
Newbie
I have a 25 year old Tyndall Nautilus DMC metal detector for which I can not find my user's manual. Looking for on-line manual or else willing to pay for hardcopy.
Tyndall Nautilus DMC detector User Manual
- Thread starter sretaw
- Start date
Jeep
Bronze Member
- Mar 27, 2008
- 1,556
- 17
- Detector(s) used
- My other detector is a helicopter
- Primary Interest:
- All Treasure Hunting
I found this:
The Nautilus is not your average hobby detector. It allows more precise adjustment of the machines
features and requires some working knowledge by the operator to achieve maximum results. The
learning curve is a little longer, but the results can be very rewarding.
The ON-OFF switch is self explanatory. A word of warning.....the last thing you should do before
storing your Nautilus is check to make sure you have not bumped this toggle type switch to the ON
position or you will start your next days hunt with dead batteries.
The MODE SELECTOR has two positions.....NON MOTION DISCRIMINATE......and.....GROUND REJECT
DISCRIMINATION. The vast majority of your detecting will be with this toggle switch in the GROUND
REJECT DISCRIMINATION mode. This brings into play both the ground balanced all metal mode and
the motion discrimination mode. Operating with your earphone switch in the STEREO position, you
will get a low tone all metal sound in one ear and a high tone motion discriminate sound in your other
ear and can adjust the volume to each ear. Sort of like detecting in stereo with full sound effects. If
you place your earphone switch to the MONO position, you will hear both modes in both ear sets.
Hunting in MONO is about the same tone-on-tone system known as MIXED MODE on some other
machines. I prefer using STEREO with the all metal signal coming in the right ear and the
discrimination mode coming in the left ear The low tone sound from the all metal mode in your right
ear will allow you to judge a targets SIZE, SHAPE, DEPTH and CONDUCTANCE. The higher pitched
beep from the motion discriminate mode in your left ear will alert you to the fact that your coil is
passing over a target which you have not discriminated out. Being able to hear and compare signals
from both modes at the same time provides you with the information you will use to identify the more
desirable targets.
The red RE-TUNE BUTTON is used to re-set your threshold sound as necessary and also to DE-TUNE
the all metal mode when pinpointing. The threshold sound will be a slight low pitched hum in your
right ear coming only from the all metal mode. The discrimination mode is set up as a silent search
motion mode and will signal only when an accepted target is encountered. To make your original
THRESHOLD adjustment, hold in the RE-TUNE button and turn the threshold adjustment clockwise
until you hear a slight hum. This slight hum will be your constant reference point from which you will
be able to determine the all metal audio characteristics of each target encountered.
The Nautilus's all metal mode is a threshold based mode. You hear a slight threshold hum in your
right ear at all times and that sound increases to indicate targets as you pass your coil over them.
The threshold sound decreases or goes quite to indicate an increase in non-conductive minerals.
The all metal mode doesn't cull anything, you will hear a change in threshold sound for everything in
the ground......and that includes a change in ground minerals. .
The Nautilus allows you to adjust the amount of voltage applied to the transmitter coil of your search
coil with the knob marked TRANSMIT POWER. This is a feature you wont find on most other
detectors and is one of the reasons the Nautilus is known as a very deep detector. The 6 volt
position of this control approximately equals the transmit power of an average detector. As you turn
the control on up toward the 44 volt position, you increase depth and sensitivity of the Nautilus. This
is not a linear control as far as depth is concerned, In other words, position 12 on the control is not
twice as deep as position 6. You can experience instability, indicated by a wavering threshold sound,
if you try to run this control too high at some sites. As a general rule, don't try to over-power a site,
just adjust as high as you can go while maintaining a stable detector.
Both modes of the Nautilus have their own SENSITIVITY control. The sensitivity control on the left
side of the control box is for the motion discrimination and the one on the right side is for the all
metal mode. The recommended sensitivity settings is 9 for discrimination and 3 for all metal. At
these settings, comparing the audio of the two modes will allow you to determine the quality of a
target. At these settings, the discrimination mode is deeper than the all metal mode. Having
separate sensitivity adjustments makes for a very versatile detector as you learn to make these
adjustments to achieve the results you wont.
The Nautilus DMCIIBa does not provide external sensitivity adjustments and it is my understanding
that its internal sensitivity settings are permanently set at 9 and 3 respectively.
Set the GROUND BALANCE adjustment at 65 prior to adjusting the search loop balance. I don't know
that this is necessary, it is just something I do as 65 represents a setting for average ground
conditions.
Set the AUTO TUNE switch to the OFF position prior to adjusting search loop balance. You can also
perform the search loop balance procedure with the auto-tune switch turned ON but I think it is more
accurate to do this procedure with auto-tune turned OFF.
The Nautilus is the only machine I know of that has the SEARCH LOOP BALANCE feature. The
transmit and receive windings of a coil are precisely placed and epoxied into permanent positions. If
either coil is moved out of position, a signal will be created that can interfere with proper operation of
the coil. The contracting and expansion of the coils physical structure due to changes in
temperature can cause these minuscule changes in the coils operation. This can be happening to all
detector coils but seems to be a somewhat minor effect that it is ignored in other detector designs.
The electronic components in a coils circuits can also change value due to aging over a period of
time. The R and C controls of the SEARCH LOOP BALANCE system allows us to finely tune the search
loops coil to insure more precise operation.
Hold the search coil up to about waist level while performing search loop balance. This insures that
you are balancing the coil only and is not being influenced by targets or ground minerals.
Check that all metal mode sensitivity is set at 3
The Transmit Power Control can be set anywhere between 6 and 44 as long as you can maintain a
steady threshold sound. If threshold becomes unstable at higher settings, lower the transmit voltage
until you can maintain a stable sounding threshold.
Check AUTO TUNE switch turned OFF
If necessary, reset threshold by holding in the RETUNE push button and adjust threshold .
Adjust R and C controls to approximately 12:00 position
Turn SLB (SEARCH LOOP BALANCE) switch ON
Turn either R or C control to the left or right from their center position until the threshold tone
disappears (if you have trouble getting the threshold sound to disappear, lower transmit power.
After the threshold tone nulls out, temporarily depress the RETUNE button to bring back the
threshold sound. Do not re-adjust the threshold, just punching the retune button should bring back
your original adjustment.
Repeat the above procedure until the tone no longer disappears but just starts to rise.
Stop adjusting at this point. Now if you turn the R (or C) control just a small amount left or right you
will hear a small dip or null in the threshold volume. The objective is to have the smallest and lowest
sounding null you can get. Leave the R or C control to this nulled position. You can now adjust your
transmit power to a higher setting if desired as long as you can still maintain a stable threshold
sound after doing so. Turn SLB switch OFF. Search loop balance should be checked every 15
minutes for the first hour until the search loop has reached ambient temperature. (for example:
taking detector out of car which has temperature of 70 degrees into an environment of 30 degrees).
The R and C controls can be adjusted the next day from the point they were last set, assuming they
have not been accidentally moved. SLB should be checked after every 10 degree change in
temperature.
Adjusting the SLB with the AUTO-tune turned ON is a little simpler. You don't have to keep manually
retuning after each adjustment of the R or C control because the auto-tuning will be automatically
returning threshold to where you originally set it. Simply turn the R and C controls either left or right
until you reach a point where the threshold temporarily nulls out. Once you have located that nulled
spot, adjust back and forth until it sounds like you are in the center of the nulled area. This null point
should be anywhere between the 9:00 position and the 3:00 position. If the coil adjusts out of this
range, the coil is going bad and needs repair.
Special care should be exercised in setting and maintaining a proper GROUND BALANCE. Ground
balance allows the detector to ignore ground minerals in order to reach greater depths and have
maximum sensitivity to all targets. Ground balance simply tunes out the sound of the ground
minerals and allows better sounds from targets. Keep in mind that the ground minerals are still
there, they have not "disappeared". They are still there and limiting your detecting depth and,
depending on the degree of mineralization and the type of minerals, can cause erratic detector
operation. At some sites, it may be necessary to lower coil voltage and sensitivity to stabilize
detector operation. The ground balance control of the Nautilus is very precise with an eight turn
vernier control and a wide adjustment range calibrated from 0 to 100. Since the Nautilus all metal
mode is threshold based and you will be listening to that threshold sound in one ear at all times, you
will immediately be made aware of changing ground minerals and can adjust accordingly. Simply
pump the coil up and down from about 12 inches over a section of ground which otherwise has no
targets, and you can frequently check ground balance as you hunt. You can ground balance with the
AUTO TUNE turned ON or OFF.
Ground balancing with the AUTO-TUNE turned OFF is probably more accurate but requires you to
retune threshold sound as necessary after each adjustment.
Set THRESHOLD to slight hum.
Locate a section of ground that is clear of all targets. Pump the coil from about 12 inches high to
within l inch of the ground and listen to the effect on threshold sound. If threshold sound increases,
you will have to adjust the ground balance control down (counterclockwise). If threshold sound
decreases, you will have to adjust the ground balance control up (clockwise).
Raise the coil, make a very slight adjustment up or down as necessary, hit the retune button to
return threshold to its original setting and lower the coil to the ground to re-check for effect.
Continue making small incremental adjustments until the sound of your threshold is the same with
the coil at 12 inches high as it is with the coil 1 inch from the ground. Retuning will be necessary after
each ground balance adjustment.
You may prefer to ground balance with the auto tune switch turned ON so that retuning the threshold
is not necessary. The purpose of the auto tune circuitry is to maintain the all metal threshold volume
to your original volume setting. Any increase or decrease in threshold sound will automatically be
tuned out and threshold returned to original volume. This requires you to have the coil in continuous
motion in order to hear targets. It effects only the all metal mode and creates, in effect, a MOTION
ALL METAL MODE. To ground balance with auto tune turned ON:
Set THRESHOLD to slight hum.
Locate a section of ground that is clear of all targets. Pump the coil from 12 inches high to within 1
inch of the ground and listen to the effect on threshold sound. The threshold volume should be the
same at 12 inches as it is at 1 inch. While continuously pumping the coil at the ground, increase or
decrease the ground balance control setting until proper ground balance is achieved. Manual
retuning is not required since auto tuning is taking place but you do have to keep the coil moving up
and down fast enough while pumping the coil to overcome the auto tune effect.
With the excellent GROUND BALANCE control of the Nautilus, there is no excuse for not maintaining
a proper ground balance at all times. As the ground minerals change, a new ground balance will be
required. Most sites will have very little mineral change but why take chances? Check ground
balance often as you hunt by finding a section of ground without targets and pump the coil at it and
reset ground balance as necessary. Some sites can have variable ground minerals to such a degree
that ground balancing may be required every few feet. The ground balance setting effects both the
all metal mode and the discrimination mode. You can get much more accurate and cleaner sounding
discrimination with proper ground balance. If a change in ground minerals results in a negative
ground balance on the Nautilus, it can cause falsing sounds in the discrimination mode. Think of a
ground balance as being the reference point from which all the other circuits work and you will
realize the importance of maintaining proper ground balance. Keep the ground minerals balanced
out and you will get the maximum depth and sensitivity to all targets. You can judge the degree of
mineralization by where the ground balances out. Above 65 is higher than average minerals, below
65 is milder ground. Settings higher than 65 is an indication of more non-conductive minerals. If the
setting goes too much below 65, it is indication that your ground has low mineralization.
The DISCRIMINATION control of the Nautilus is an 8 turn vernier control calibrated from 0 to 100.
Because of its wide range of adjustment, you can get very accurate with your degree of
discrimination. The discrimination setting that discriminates a certain item can vary depending on
site conditions. A setting that discriminates a specific target at a dry ground site will not be the same
as a setting for a high moisture site. The same applies to low and high minerals. Set your
discrimination to eliminate audio over the lowest conductor item you don't wont to dig and then
gradually adjust as you hunt to take into consideration the site conditions. It is best to keep adjusting
the discrimination down until you start digging more trash than you wont..... then turn it up just a tad.
If you wont to just use the Nautilus as a single tone motion discriminator, turn the all metal sensitivity
to Zero and you will no longer hear the all metal signal. This is your old familiar "beep/dig" or "no
beep/no dig" type of detecting and will not provide you with all the target information as the full
fledged Nautilus Dual Mode System.
With the Dual Mode system where you are listening to both the all metal mode and the discrimination
mode at the same time, it is best to use very low discrimination settings and then let your ears do
the discriminating. The discrimination mode allows you to hear the range of conductive targets you
have selected while the all metal mode audio helps determine the targets SIZE, SHAPE, DEPTH, and
CONDUCTIVITY. Any target you cannot define as "bad" should be dug. You will dig lots of trash to
begin with as you learn the Nautilus audio system but with time and experience, your good target to
bad target ratio will improve. My experience has been that many of the targets that I could not
identify as positively bad turned out to be something good. For example, I recently heard a signal that
had some indications of rusty iron but also some indications of higher conductance. My guess was a
small rusty iron item but since I couldn't positively identify the target as bad, I dug it. The target was
a large mans silver ring snuggled tightly to a rusty bottle cap. A couple of days ago, a beautiful
braided 14K gold ring popped out of the ground even though I was convinced I was probably digging
the ring off of a ring tab with the beaver tail broken off. I dig lots of those ring tab rings because it is
difficult to tell the difference between a jewelry ring and ring tab ring That pull tab ring reads pull tab on
a metered detector. After gaining experience with the Nautilus, you will realize that its all metal
audio, combined with discrimination, combined with your decision making ability, can be very
accurate and will often get you targets that have been missed by other detectors.
The auto-tune switch allows you to choose between a true all metal mode with manual retune and
an all metal mode with automatic tuning. In TRUE ALL METAL MODE (Auto tune switch turned OFF)
passing your coil over a target will cause an increase in threshold sound in your right earphone. If
you stop the coil over the target, the target will continue to sound off as long as the coil covers the
target. In this mode, the strength of the low tone signal gives some indication of DEPTH and
CONDUCTIVITY. The SIZE of the target is indicated by the length or width of the target sound as your
coil passes over it. By careful DE-TUNING over the target area, you can determine a targets SHAPE.
This mode has less sensitivity to the more conductive targets and will indicate them with weaker,
more narrow hits. Lower conductive targets give a louder wider sounding hit. In this mode, your
original threshold setting may sometimes "drift", becoming lower or higher volume than you
originally set it. You can return to original threshold at any time by punching the re-tune button with
the coil held about knee high above the ground or over a section of ground that does not contain any
targets. You can use the retune button for PINPOINTING while in true all metal mode by simply
punching the retune button while the coil is over the target area. Punching the retune button a few
times and DE-TUNING over the target area will "shrink" the target signal until the target sounds off
only in the very center of the coil, giving you a very accurate pinpoint. True all metal mode is best
used at sites where targets are not located close together and all "long", large, and very loud
sounding targets should be DE-TUNED and investigated.
AT trashy sites it is better to use the AUTO-TUNED ALL METAL MODE. In this mode, any increase or
decrease in threshold sound will be automatically tuned out as auto-tuning attempts to maintain a
steady threshold sound. This, in effect, makes the Auto tune mode a motion mode because the coil
must be kept in motion to hear the targets. If the coil is stopped over a target, the sound of the target
will be tuned out as threshold is returned back to it's normal low volume. The purpose of auto tuning
is to maintain a steady threshold sound, ignoring small volume changes caused by variable ground
minerals, sloppy coil movements by the operator, and uneven ground surfaces. This feature allows
actual target sounds to be more easily recognized against the background sound of a steady
threshold. Different manufacturers have different speeds of auto-tuning. The Nautilus has a fast
auto-tune and will quickly tune out the sound of most targets in approximately one to two seconds
depending on target depth and size.. It does, however, rapidly retune to normal threshold sound after
it passes over a target so that it can quickly sound off on another target located nearby. This fast
recovery from target to target allows us to hear individual targets located close together similar to
the fast target recovery being heard from the discrimination mode. You do not, however, get as
much audio information from your targets in this mode unless you maintain very good coil
discipline. If Coil movement over a target is too slow, the sound of the target is being tuned out
before you get enough information to determine its size, shape, depth, and conductance. This mode
requires a certain coil sweep speed to get good audio information from a target, not too fast, not to
slow. Practice your coil sweep speeds over both good targets and trash targets laid out on a target
free section ground. The proper coil sweep speed will make each type target sound the same each
time you pass over it. This is critical as these are the sounds that will help you classify each target.
Iron will be the widest sounding targets. Targets of coin size and similar conductance will sound
narrow with weaker volume. Targets of mid-conductance range like pull-tabs and brass will sound a
little stronger and wider than coins but not as wide as iron. Without going into detail about all the
audio information you can get from targets in the auto-tuned all metal mode here, it is important to
note again that coil sweep speed must be co-ordinated to auto-tuning speed in order to hear a
targets audio characteristics.
PINPOINTING in the Auto tune mode can be done best by raising the coil approximately 6 inches
and moving back and forth over the target to locate it as it beeps only under the very center of the
coil. You will be hearing both the all metal sound in your right ear and the discrimination sound in
your left ear as you pinpoint in this manner. You can get some DEPTH, SIZE and CONDUCTANCE
information about a target by pinpointing with a raised coil. Small, higher conductive targets signals
will fade rapidly in both signal strength and width as the coil is raised. Most less conductive targets
and larger targets signal strength will not fade as rapidly as you raise the coil and tend to keep
reading wider than coin type targets at this raised coil height.
The Nautilus is an excellent motion discriminator with great depth and sensitivity. Simply turn the all
metal sensitivity adjustment to the 0 position to shut off the sound of all metal mode and all you will
hear is the high tone of the discrimination mode. Switching your earphones from Stereo to Mono will
give you the discrimination beep in both ears. It is important to remember though that the
discrimination mode depends on the ground balance of the all metal mode as a reference point for
proper circuit operation and continue to make ground balance adjustments as necessary. False
signals from the discrimination mode is an indication that re-balancing to ground is necessary.
The Nautilus is not your average hobby detector. It allows more precise adjustment of the machines
features and requires some working knowledge by the operator to achieve maximum results. The
learning curve is a little longer, but the results can be very rewarding.
The ON-OFF switch is self explanatory. A word of warning.....the last thing you should do before
storing your Nautilus is check to make sure you have not bumped this toggle type switch to the ON
position or you will start your next days hunt with dead batteries.
The MODE SELECTOR has two positions.....NON MOTION DISCRIMINATE......and.....GROUND REJECT
DISCRIMINATION. The vast majority of your detecting will be with this toggle switch in the GROUND
REJECT DISCRIMINATION mode. This brings into play both the ground balanced all metal mode and
the motion discrimination mode. Operating with your earphone switch in the STEREO position, you
will get a low tone all metal sound in one ear and a high tone motion discriminate sound in your other
ear and can adjust the volume to each ear. Sort of like detecting in stereo with full sound effects. If
you place your earphone switch to the MONO position, you will hear both modes in both ear sets.
Hunting in MONO is about the same tone-on-tone system known as MIXED MODE on some other
machines. I prefer using STEREO with the all metal signal coming in the right ear and the
discrimination mode coming in the left ear The low tone sound from the all metal mode in your right
ear will allow you to judge a targets SIZE, SHAPE, DEPTH and CONDUCTANCE. The higher pitched
beep from the motion discriminate mode in your left ear will alert you to the fact that your coil is
passing over a target which you have not discriminated out. Being able to hear and compare signals
from both modes at the same time provides you with the information you will use to identify the more
desirable targets.
The red RE-TUNE BUTTON is used to re-set your threshold sound as necessary and also to DE-TUNE
the all metal mode when pinpointing. The threshold sound will be a slight low pitched hum in your
right ear coming only from the all metal mode. The discrimination mode is set up as a silent search
motion mode and will signal only when an accepted target is encountered. To make your original
THRESHOLD adjustment, hold in the RE-TUNE button and turn the threshold adjustment clockwise
until you hear a slight hum. This slight hum will be your constant reference point from which you will
be able to determine the all metal audio characteristics of each target encountered.
The Nautilus's all metal mode is a threshold based mode. You hear a slight threshold hum in your
right ear at all times and that sound increases to indicate targets as you pass your coil over them.
The threshold sound decreases or goes quite to indicate an increase in non-conductive minerals.
The all metal mode doesn't cull anything, you will hear a change in threshold sound for everything in
the ground......and that includes a change in ground minerals. .
The Nautilus allows you to adjust the amount of voltage applied to the transmitter coil of your search
coil with the knob marked TRANSMIT POWER. This is a feature you wont find on most other
detectors and is one of the reasons the Nautilus is known as a very deep detector. The 6 volt
position of this control approximately equals the transmit power of an average detector. As you turn
the control on up toward the 44 volt position, you increase depth and sensitivity of the Nautilus. This
is not a linear control as far as depth is concerned, In other words, position 12 on the control is not
twice as deep as position 6. You can experience instability, indicated by a wavering threshold sound,
if you try to run this control too high at some sites. As a general rule, don't try to over-power a site,
just adjust as high as you can go while maintaining a stable detector.
Both modes of the Nautilus have their own SENSITIVITY control. The sensitivity control on the left
side of the control box is for the motion discrimination and the one on the right side is for the all
metal mode. The recommended sensitivity settings is 9 for discrimination and 3 for all metal. At
these settings, comparing the audio of the two modes will allow you to determine the quality of a
target. At these settings, the discrimination mode is deeper than the all metal mode. Having
separate sensitivity adjustments makes for a very versatile detector as you learn to make these
adjustments to achieve the results you wont.
The Nautilus DMCIIBa does not provide external sensitivity adjustments and it is my understanding
that its internal sensitivity settings are permanently set at 9 and 3 respectively.
Set the GROUND BALANCE adjustment at 65 prior to adjusting the search loop balance. I don't know
that this is necessary, it is just something I do as 65 represents a setting for average ground
conditions.
Set the AUTO TUNE switch to the OFF position prior to adjusting search loop balance. You can also
perform the search loop balance procedure with the auto-tune switch turned ON but I think it is more
accurate to do this procedure with auto-tune turned OFF.
The Nautilus is the only machine I know of that has the SEARCH LOOP BALANCE feature. The
transmit and receive windings of a coil are precisely placed and epoxied into permanent positions. If
either coil is moved out of position, a signal will be created that can interfere with proper operation of
the coil. The contracting and expansion of the coils physical structure due to changes in
temperature can cause these minuscule changes in the coils operation. This can be happening to all
detector coils but seems to be a somewhat minor effect that it is ignored in other detector designs.
The electronic components in a coils circuits can also change value due to aging over a period of
time. The R and C controls of the SEARCH LOOP BALANCE system allows us to finely tune the search
loops coil to insure more precise operation.
Hold the search coil up to about waist level while performing search loop balance. This insures that
you are balancing the coil only and is not being influenced by targets or ground minerals.
Check that all metal mode sensitivity is set at 3
The Transmit Power Control can be set anywhere between 6 and 44 as long as you can maintain a
steady threshold sound. If threshold becomes unstable at higher settings, lower the transmit voltage
until you can maintain a stable sounding threshold.
Check AUTO TUNE switch turned OFF
If necessary, reset threshold by holding in the RETUNE push button and adjust threshold .
Adjust R and C controls to approximately 12:00 position
Turn SLB (SEARCH LOOP BALANCE) switch ON
Turn either R or C control to the left or right from their center position until the threshold tone
disappears (if you have trouble getting the threshold sound to disappear, lower transmit power.
After the threshold tone nulls out, temporarily depress the RETUNE button to bring back the
threshold sound. Do not re-adjust the threshold, just punching the retune button should bring back
your original adjustment.
Repeat the above procedure until the tone no longer disappears but just starts to rise.
Stop adjusting at this point. Now if you turn the R (or C) control just a small amount left or right you
will hear a small dip or null in the threshold volume. The objective is to have the smallest and lowest
sounding null you can get. Leave the R or C control to this nulled position. You can now adjust your
transmit power to a higher setting if desired as long as you can still maintain a stable threshold
sound after doing so. Turn SLB switch OFF. Search loop balance should be checked every 15
minutes for the first hour until the search loop has reached ambient temperature. (for example:
taking detector out of car which has temperature of 70 degrees into an environment of 30 degrees).
The R and C controls can be adjusted the next day from the point they were last set, assuming they
have not been accidentally moved. SLB should be checked after every 10 degree change in
temperature.
Adjusting the SLB with the AUTO-tune turned ON is a little simpler. You don't have to keep manually
retuning after each adjustment of the R or C control because the auto-tuning will be automatically
returning threshold to where you originally set it. Simply turn the R and C controls either left or right
until you reach a point where the threshold temporarily nulls out. Once you have located that nulled
spot, adjust back and forth until it sounds like you are in the center of the nulled area. This null point
should be anywhere between the 9:00 position and the 3:00 position. If the coil adjusts out of this
range, the coil is going bad and needs repair.
Special care should be exercised in setting and maintaining a proper GROUND BALANCE. Ground
balance allows the detector to ignore ground minerals in order to reach greater depths and have
maximum sensitivity to all targets. Ground balance simply tunes out the sound of the ground
minerals and allows better sounds from targets. Keep in mind that the ground minerals are still
there, they have not "disappeared". They are still there and limiting your detecting depth and,
depending on the degree of mineralization and the type of minerals, can cause erratic detector
operation. At some sites, it may be necessary to lower coil voltage and sensitivity to stabilize
detector operation. The ground balance control of the Nautilus is very precise with an eight turn
vernier control and a wide adjustment range calibrated from 0 to 100. Since the Nautilus all metal
mode is threshold based and you will be listening to that threshold sound in one ear at all times, you
will immediately be made aware of changing ground minerals and can adjust accordingly. Simply
pump the coil up and down from about 12 inches over a section of ground which otherwise has no
targets, and you can frequently check ground balance as you hunt. You can ground balance with the
AUTO TUNE turned ON or OFF.
Ground balancing with the AUTO-TUNE turned OFF is probably more accurate but requires you to
retune threshold sound as necessary after each adjustment.
Set THRESHOLD to slight hum.
Locate a section of ground that is clear of all targets. Pump the coil from about 12 inches high to
within l inch of the ground and listen to the effect on threshold sound. If threshold sound increases,
you will have to adjust the ground balance control down (counterclockwise). If threshold sound
decreases, you will have to adjust the ground balance control up (clockwise).
Raise the coil, make a very slight adjustment up or down as necessary, hit the retune button to
return threshold to its original setting and lower the coil to the ground to re-check for effect.
Continue making small incremental adjustments until the sound of your threshold is the same with
the coil at 12 inches high as it is with the coil 1 inch from the ground. Retuning will be necessary after
each ground balance adjustment.
You may prefer to ground balance with the auto tune switch turned ON so that retuning the threshold
is not necessary. The purpose of the auto tune circuitry is to maintain the all metal threshold volume
to your original volume setting. Any increase or decrease in threshold sound will automatically be
tuned out and threshold returned to original volume. This requires you to have the coil in continuous
motion in order to hear targets. It effects only the all metal mode and creates, in effect, a MOTION
ALL METAL MODE. To ground balance with auto tune turned ON:
Set THRESHOLD to slight hum.
Locate a section of ground that is clear of all targets. Pump the coil from 12 inches high to within 1
inch of the ground and listen to the effect on threshold sound. The threshold volume should be the
same at 12 inches as it is at 1 inch. While continuously pumping the coil at the ground, increase or
decrease the ground balance control setting until proper ground balance is achieved. Manual
retuning is not required since auto tuning is taking place but you do have to keep the coil moving up
and down fast enough while pumping the coil to overcome the auto tune effect.
With the excellent GROUND BALANCE control of the Nautilus, there is no excuse for not maintaining
a proper ground balance at all times. As the ground minerals change, a new ground balance will be
required. Most sites will have very little mineral change but why take chances? Check ground
balance often as you hunt by finding a section of ground without targets and pump the coil at it and
reset ground balance as necessary. Some sites can have variable ground minerals to such a degree
that ground balancing may be required every few feet. The ground balance setting effects both the
all metal mode and the discrimination mode. You can get much more accurate and cleaner sounding
discrimination with proper ground balance. If a change in ground minerals results in a negative
ground balance on the Nautilus, it can cause falsing sounds in the discrimination mode. Think of a
ground balance as being the reference point from which all the other circuits work and you will
realize the importance of maintaining proper ground balance. Keep the ground minerals balanced
out and you will get the maximum depth and sensitivity to all targets. You can judge the degree of
mineralization by where the ground balances out. Above 65 is higher than average minerals, below
65 is milder ground. Settings higher than 65 is an indication of more non-conductive minerals. If the
setting goes too much below 65, it is indication that your ground has low mineralization.
The DISCRIMINATION control of the Nautilus is an 8 turn vernier control calibrated from 0 to 100.
Because of its wide range of adjustment, you can get very accurate with your degree of
discrimination. The discrimination setting that discriminates a certain item can vary depending on
site conditions. A setting that discriminates a specific target at a dry ground site will not be the same
as a setting for a high moisture site. The same applies to low and high minerals. Set your
discrimination to eliminate audio over the lowest conductor item you don't wont to dig and then
gradually adjust as you hunt to take into consideration the site conditions. It is best to keep adjusting
the discrimination down until you start digging more trash than you wont..... then turn it up just a tad.
If you wont to just use the Nautilus as a single tone motion discriminator, turn the all metal sensitivity
to Zero and you will no longer hear the all metal signal. This is your old familiar "beep/dig" or "no
beep/no dig" type of detecting and will not provide you with all the target information as the full
fledged Nautilus Dual Mode System.
With the Dual Mode system where you are listening to both the all metal mode and the discrimination
mode at the same time, it is best to use very low discrimination settings and then let your ears do
the discriminating. The discrimination mode allows you to hear the range of conductive targets you
have selected while the all metal mode audio helps determine the targets SIZE, SHAPE, DEPTH, and
CONDUCTIVITY. Any target you cannot define as "bad" should be dug. You will dig lots of trash to
begin with as you learn the Nautilus audio system but with time and experience, your good target to
bad target ratio will improve. My experience has been that many of the targets that I could not
identify as positively bad turned out to be something good. For example, I recently heard a signal that
had some indications of rusty iron but also some indications of higher conductance. My guess was a
small rusty iron item but since I couldn't positively identify the target as bad, I dug it. The target was
a large mans silver ring snuggled tightly to a rusty bottle cap. A couple of days ago, a beautiful
braided 14K gold ring popped out of the ground even though I was convinced I was probably digging
the ring off of a ring tab with the beaver tail broken off. I dig lots of those ring tab rings because it is
difficult to tell the difference between a jewelry ring and ring tab ring That pull tab ring reads pull tab on
a metered detector. After gaining experience with the Nautilus, you will realize that its all metal
audio, combined with discrimination, combined with your decision making ability, can be very
accurate and will often get you targets that have been missed by other detectors.
The auto-tune switch allows you to choose between a true all metal mode with manual retune and
an all metal mode with automatic tuning. In TRUE ALL METAL MODE (Auto tune switch turned OFF)
passing your coil over a target will cause an increase in threshold sound in your right earphone. If
you stop the coil over the target, the target will continue to sound off as long as the coil covers the
target. In this mode, the strength of the low tone signal gives some indication of DEPTH and
CONDUCTIVITY. The SIZE of the target is indicated by the length or width of the target sound as your
coil passes over it. By careful DE-TUNING over the target area, you can determine a targets SHAPE.
This mode has less sensitivity to the more conductive targets and will indicate them with weaker,
more narrow hits. Lower conductive targets give a louder wider sounding hit. In this mode, your
original threshold setting may sometimes "drift", becoming lower or higher volume than you
originally set it. You can return to original threshold at any time by punching the re-tune button with
the coil held about knee high above the ground or over a section of ground that does not contain any
targets. You can use the retune button for PINPOINTING while in true all metal mode by simply
punching the retune button while the coil is over the target area. Punching the retune button a few
times and DE-TUNING over the target area will "shrink" the target signal until the target sounds off
only in the very center of the coil, giving you a very accurate pinpoint. True all metal mode is best
used at sites where targets are not located close together and all "long", large, and very loud
sounding targets should be DE-TUNED and investigated.
AT trashy sites it is better to use the AUTO-TUNED ALL METAL MODE. In this mode, any increase or
decrease in threshold sound will be automatically tuned out as auto-tuning attempts to maintain a
steady threshold sound. This, in effect, makes the Auto tune mode a motion mode because the coil
must be kept in motion to hear the targets. If the coil is stopped over a target, the sound of the target
will be tuned out as threshold is returned back to it's normal low volume. The purpose of auto tuning
is to maintain a steady threshold sound, ignoring small volume changes caused by variable ground
minerals, sloppy coil movements by the operator, and uneven ground surfaces. This feature allows
actual target sounds to be more easily recognized against the background sound of a steady
threshold. Different manufacturers have different speeds of auto-tuning. The Nautilus has a fast
auto-tune and will quickly tune out the sound of most targets in approximately one to two seconds
depending on target depth and size.. It does, however, rapidly retune to normal threshold sound after
it passes over a target so that it can quickly sound off on another target located nearby. This fast
recovery from target to target allows us to hear individual targets located close together similar to
the fast target recovery being heard from the discrimination mode. You do not, however, get as
much audio information from your targets in this mode unless you maintain very good coil
discipline. If Coil movement over a target is too slow, the sound of the target is being tuned out
before you get enough information to determine its size, shape, depth, and conductance. This mode
requires a certain coil sweep speed to get good audio information from a target, not too fast, not to
slow. Practice your coil sweep speeds over both good targets and trash targets laid out on a target
free section ground. The proper coil sweep speed will make each type target sound the same each
time you pass over it. This is critical as these are the sounds that will help you classify each target.
Iron will be the widest sounding targets. Targets of coin size and similar conductance will sound
narrow with weaker volume. Targets of mid-conductance range like pull-tabs and brass will sound a
little stronger and wider than coins but not as wide as iron. Without going into detail about all the
audio information you can get from targets in the auto-tuned all metal mode here, it is important to
note again that coil sweep speed must be co-ordinated to auto-tuning speed in order to hear a
targets audio characteristics.
PINPOINTING in the Auto tune mode can be done best by raising the coil approximately 6 inches
and moving back and forth over the target to locate it as it beeps only under the very center of the
coil. You will be hearing both the all metal sound in your right ear and the discrimination sound in
your left ear as you pinpoint in this manner. You can get some DEPTH, SIZE and CONDUCTANCE
information about a target by pinpointing with a raised coil. Small, higher conductive targets signals
will fade rapidly in both signal strength and width as the coil is raised. Most less conductive targets
and larger targets signal strength will not fade as rapidly as you raise the coil and tend to keep
reading wider than coin type targets at this raised coil height.
The Nautilus is an excellent motion discriminator with great depth and sensitivity. Simply turn the all
metal sensitivity adjustment to the 0 position to shut off the sound of all metal mode and all you will
hear is the high tone of the discrimination mode. Switching your earphones from Stereo to Mono will
give you the discrimination beep in both ears. It is important to remember though that the
discrimination mode depends on the ground balance of the all metal mode as a reference point for
proper circuit operation and continue to make ground balance adjustments as necessary. False
signals from the discrimination mode is an indication that re-balancing to ground is necessary.
sretaw
Newbie
- Thread starter
- #3
Thanks, but I think this is for a later model, my controls are not marked such as the description suggests (for example I do not have a transmit power control) and my machine (an early DMC) operates on only two 9 volt batteries, not 44 volts. Thanks for the research, though. My top six controls are three each for discrimination and ground balance, tune and sensitivity for both and a ten turn control. The batteries have two switches on either side of them, now those switches are the things I am not certain of their use. Headphone end of the detector has on-off switch and single-dual tone switch as well as red button to manually retune.
Jeep
Bronze Member
- Mar 27, 2008
- 1,556
- 17
- Detector(s) used
- My other detector is a helicopter
- Primary Interest:
- All Treasure Hunting
There don't seem to be a website for them. I know that they changed there name from Tyndall Electronics to Nautilus Metal Detectors Inc.
Try writing or calling the factory in Coats, NC:
Nautilus Metal Detectors Inc., 29 W. Lemon St., Coats, NC 27521, call 910-897-7950
Try writing or calling the factory in Coats, NC:
Nautilus Metal Detectors Inc., 29 W. Lemon St., Coats, NC 27521, call 910-897-7950
MountaineerLegion
Newbie
Welcome to TreasureNet MountaineerLegion...
I don't know about the switches, but that detector SURE harkens me back to the day when I used Bounty Hunters... AH THE GOOD OLD DAYS... I miss good old analog machines... like the TR500... simple and light.
I wonder if the companies were related somehow. The construction looks very similar.
This post almost makes me want to start collecting old detectors!
I don't know about the switches, but that detector SURE harkens me back to the day when I used Bounty Hunters... AH THE GOOD OLD DAYS... I miss good old analog machines... like the TR500... simple and light.
I wonder if the companies were related somehow. The construction looks very similar.
This post almost makes me want to start collecting old detectors!
MountaineerLegion
Newbie
Thanks for the welcome Marc. I've been told it's quite old. I've also heard from several folks that if you take the time to "learn" to use it you can be very successful at digging. Problem is I can't find anyone who can explain how to use it. I keep hearing that with this machine you really have to listen to it but that it will tell you everything you want to know about whats down in the dirt......just wish I could find someone who knew what the switches did so I could tell if I'm listening to the right stuff 
Marc said:Welcome to TreasureNet MountaineerLegion...
I don't know about the switches, but that detector SURE harkens me back to the day when I used Bounty Hunters... AH THE GOOD OLD DAYS... I miss good old analog machines... like the TR500... simple and light.
I wonder if the companies were related somehow. The construction looks very similar.
This post almost makes me want to start collecting old detectors!
U.K. Brian
Bronze Member
- Oct 11, 2005
- 1,629
- 153
- Detector(s) used
- XLT, Whites D.F., Treasure Baron, Deepstar, Goldquest, Beachscan, T.D.I., Sovereign, 2x Nautilus, various Arado's, Ixcus Diver, Altek Quadtone, T2, Beach Hunter I.D, GS 5 pulse, Searchman 2 ,V3i
- Primary Interest:
- All Treasure Hunting
There's two Nautilus specific forums that may be able to help.
I don't think we are supposed to post links to other forums so I'll PM you.
I don't think we are supposed to post links to other forums so I'll PM you.
JohninCT
Full Member
- Apr 23, 2003
- 195
- 8
- Detector(s) used
- Pulsepower Aquastar ll, Minelab CTX 3030, Sovereign GT, Nautilus DMC2Ba. Equinox 800.
- Primary Interest:
- Beach & Shallow Water Hunting
Ok, I know this is several months old, but I have the answer for you. I have one of these also and I had labeled mine so when they wore off i could still read them. Looking at it from the coil side, the switch on the left is Auto Tune for the left side sound: up is on, down is off. The top switch on the right is Sensitivity: up is high, down is low. The lower right switch is for Auto Tune for the right side sound, up is on, down is off. Late, but I hope this helps. John
GeoW
Hero Member
- Jul 12, 2005
- 527
- 568
- Detector(s) used
- XP Deus II, XP Deus, XP ORX, Nautilus DMCllBa, Troy X5 Shadow, Tesoro Vaquero, Tesoro Outlaw
Another late reply, really late!
There is no lower switch on the right side front. What appears to be a switch in that location is actually a plug in for battery recharger.
The lower switch on the left front is the auto tune. Sensitivity switch half way up on the right front.
geo
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