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Controlling Sensitivity

All models 1992 – Current

Message from Del Romang – Founder & Chairman

“Sensitivity control is fundamental in the use of the Delkim Bite Alarm when and set up and adjusted correctly, the Delkim will give the user the highest degree of sensitivity to line movement in any known bite alarm without any false indications whatsoever. The Delkim has been in use since 1992 and over the years methods and types of line have changed. To ensure you get the very best out of your Delkims, I would advise you to read this section which has been revised in the light of experience and customer feedback since 1992. Please note that this applies to all Delkims both old and new”.


The Delkim works by sensing vibrations from contact of the line with the line guide which is directly coupled to a piezo vibration sensor. Intelligent electronics and very sophisticated controls ensure that the information from line vibrations is relayed correctly to the angler both audibly and visually.

The Delkim vibration system has unique properties that make it totally different to conventional rotation based bite alarms. For instance, vibrations can be sensed without the line actually visibly moving. This can be particularly useful in winter to pick up bites where sometimes runs do not develop and when snag fishing where early warning is essential. The ability to adjust sensitivity levels to ignore extremely slow (snails pace) line movement, is a feature that makes the Delkim particularly good in the wind, preventing false indications from wind gusts and “indicator creep”.

There is also an important phenomenon known as stiction or static friction, which can be defined as resistance to the start of movement, as opposed to simply friction, which is resistance to movement after motion has started. As stiction is overcome and the line starts to move, there is a short burst of vibrations that actually adds to the effectiveness of the Delkim vibration system and further ensures that no bites are missed.

All of the above, however, very much depends upon user set up and sensitivity level set. Experienced users have learnt to adjust sensitivity levels to suit the situation and by following these instructions the user will get the very best performance from their Delkims :-


Place your rod on the Delkim and set any visual indicators in the normal way. (It is advisable to initially set the sensitivity level slightly higher than is thought necessary, however in order to get optimum bite indication, DO NOT SET AT MAXIMUM SENSITIVITY until experience is gained.) Before clipping up or setting the free spool, starting switched to LOW (-)* gradually turn the sensitivity control (S) clockwise from 0 or minimum to a higher number, pulling the line behind the Delkim to move the visual indicator at the same time, until the required level of response is reached. If false indications occur reduce the sensitivity level gradually until they stop. If a higher level of sensitivity is required switch to HIGH (+) and repeat the process (this does not apply to the Ev Plus). You will notice that as the speed of the line is increased the sound pulses get quicker until Delkim’s unique alternating alarm mode is activated. This alternating alarm tone usually indicates a full-blooded run, often referred to as a “one toner”. This is actually a misnomer as the resulting warbling sound is actually two alternating tones which is very distinctive and unique to Delkim. It is not usually advisable to set the sensitivity so high that the alarm mode is activated as soon as the line starts to move as you will lose some speed indication.

With experience in certain conditions, it is quite possible to increase the sensitivity beyond normally acceptable levels in order to detect the presence of fish in the swim by indicating line bites and tiny tweaks and pulls.

*NOTE – The Delkim Ev Plus has one Dynamic Sensitivity Range and sensitivity adjustment should be treated like LOW (-).


Turn up the sensitivity level to maximum in the HIGH (+) setting. If false indications occur, adjust back gradually until they stop. Experiment with the HIGH (+) or LOW (-) switch position until the best setting is found for the conditions. Positioning the rod on the indicator with the rod tilting upwards slightly may sometimes give better indication and occasionally an angle adjuster may be needed to get optimum performance. Using a Delkim Plus beyond a quiver tip in conjunction with a marker board can give unbelievable bite indication.



Experience has shown that there are no hard and fast rules because of the multitude of different methods, line types and user preferences but here are a few guidelines to help you get the very best out of your Delkims


The stability of set up is very important in order to get the best from your Delkim, it will help to eliminate false bleeps and maximise the sensitivity. Goal post set ups, individual rod rests or rod pod stabilisers help stability. Swinging arm indicators or hanger supports (i.e. Delkim DuoCarbTM) may be needed in windy conditions.


Rod angle and correct butt ring positioning are critical in order to maintain good line contact with the sensor. Extreme rod angles either up or down may reduce this contact and keeping the rod roughly at 90 degrees to the Delkim will ensure perfect line contact. As long as very extreme angles are not used i.e. more than about 30 degrees up or down from horizontal, good indication should be given. Placing the butt ring up against the Delkim may allow the line to loop upwards and make poor contact with the line guide on a drop back and should be avoided if at all possible.


RULE NUMBER ONE, DON’T PUT UP WITH FALSE BEEPS, RULE NUMBER TWO, SEE RULE ONE!!!!!! False indications may occur for the following reasons:-

Sensitivity set too high If this happens simply reduce the sensitivity by turning the rotary (S) control anti-clockwise until the false bleeps stop. A change of the sensitivity range from + to – may be needed in extreme conditions.

Unwanted shock vibrations False bleeps caused by kicking or knocking the rods, debris falling on the rod or line, visual indicators moving in the wind and unstable set ups may not be eliminated by sensitivity adjustment. Sudden gusts of wind, hailstones falling on the line and very occasionally torrential rain may cause false bleeps which can be eliminated by reducing the sensitivity.

Sound vibrations It may be possible in extreme circumstances i.e. Maximum sensitivity, high volume and a specific tone frequency to get cross activation of the indicators. This is due to the vibrations from the extremely loud Delkim Plus speaker being picked up by the extreme sensitivity of the Delkim Plus vibration sensor in another head. If this is a problem just make a slight reduction to the sensitivity setting on the head giving the false indication or change the tone setting or reduce the volume on the head that is making it give the false indication. This may be more noticeable when a Delkim Plus is switched on but has no line over the sensor, allowing it to vibrate undampened – if this is the case just switch it off until it is going to be used.


If maximum indication is required, then in practical terms this can be defined as the highest level of sensitivity that can be used dependant upon conditions, line tension, type & diameter, indicator weights, range and fish activity without false indications. It may be possible to set very high sensitivity levels without false indications even as far as 6 in HIGH (+) with certain set ups but experience will be needed to interpret some of the indications. When high sensitivity levels are set there may be a loss of line speed/beep speed relationship whereby relatively slow movement could be misinterpreted as a full-blooded run. Experience will be needed in certain situations where the user may decide to tolerate some false beeps in order to deliberately maintain a very high sensitivity setting.


The Delkim works on both vibration and line friction and, in general, low diameter and low friction lines need a slightly higher sensitivity setting. The exceptions to this are braids, which, although low in diameter are generally not as smooth as nylons and also due to their non-stretch properties, transmit vibrations better and therefore may need a lower setting. Less line tension, usually governed by the weight or tension setting of the visual indicator, may require higher sensitivity settings. There is a point reached, however, when increasing the line tension can have a dampening effect on the sensor which means that the sensitivity control needs increasing in order to maintain the optimum sensitivity – trial and error is needed to arrive at the optimum setting.


Fishing at long range generally requires a higher sensitivity setting as the visual indicator movement expected is generally less.


The Delkim is extremely effective for this method and it has major advantages over any roller based system. The sensitivity level can be boosted, if needed, to indicate movement just by the weight of the line touching the line guide with no tension. It must be understood that if the line is extremely slack it may not be making good contact with the line guide. Higher diameter and stiffer lines can form coils which can make this worse. With slack lining as a run develops tension increases and any coils straighten out as soon as the slack line is taken up and the visual indicator or bobbin rises. The user can choose to use very high sensitivity where indication is given as soon as the line moves, before the slack is taken up or a lower sensitivity to indicate only when the visual indicator starts to rise and the line is under tension.


In extreme conditions where wind, waves, current and undertow are causing false indications, the LOW (-) switch setting may be needed. It is still possible to pick up quite small tweaks or dropbacks, even in relatively low sensitivity settings. On the other hand if a lot of line tension is being used it is also surprising how high the sensitivity can be set without any false indications.

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