Morse Code Keys & Keyers: CW keys

There is a wide assortment of different types of Morse code keys, keyers and paddles or CW keys used in radio communications and in particular within amateur radio or ham radio.


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There are several different type of Morse key or CW key. Straight keys, hand keys mechanical bug keys, el-bugs, paddles, single paddles, iambic paddles are all names for various forms of Morse key.

Whilst there are many different types of Morse key or CW key, the various types of key can be used in different ways, and different people have different requirements and preferences.

The different types of Morse key can be used for different purposes, so sometimes it is necessary to choose the right CW key for the right occasion. Sometimes, people may have two Morse keys wired in parallel to meet the different demands of different occasions.

A Morse key manufactured by the Clipsal company in Australia in the early 1900s

Morse key history

The Morse key has undergone a considerable amount of development and it has been the subject of a large number of patents.

Note on Morse Key History:

The Morse key developed from the first very simple 'Correspondent' key through later developments including the 'Lever Correspondent' to steel lever keys and many more versions of straight keys. Sideswipers started to reduce the number of movements required, but the mechanical bug was then introduced and this increased the sending speeds as well as reducing the strain on operators. With electronics becoming more widespread electronic keyers were introduced producing both dots and dashes and many new transmitters / transceivers included the electronics thereby requiring only a paddle externally.

Read more about Morse key history.

Types of Morse key

There are several types of Morse key and keyer that can be used today, ranging from "low-tech" hand keys right through to highly sophisticated electronic keyers using the using very complicated software and digital techniques. Broadly speaking they can be grouped into the following areas.

The various types of Morse key are outlined and detailed below.

Straight Morse key

The straight Morse key is still in widespread use by many Morse enthusiasts including ham radio operators. The basic key consists of a lever with a bearing of some form in the centre. A handle on one end is moved up and down to make and break a contact and thereby provide the keyed signal.

A typical steel lever Morse key - manual keys like this are often called a straight Morse key or hand key
A steel lever Morse key

There are many types of straight Morse key that are available. Some new straight Morse keys can be bought and it is also possible to buy older ones quite cheaply on second had sites as well.

When choosing a key for personal use, it is necessary to have one that feels comfortable. It is very much a matter of personal preference, and there is a wide selection from which to choose.

The adjustment of the Morse key is also important. The gap between the contacts should be adjusted to suit. Often wider gaps are used for slower speeds where it is possible to have time for the additional movement, and much narrower gaps are used for faster speeds. The key should also be mounted so that the wrist is supported, and this is important when long spells of operating are envisaged.

Sideswiper Morse key

Although the sideswiper Morse key was a major stepping stone in the development of Morse key technology, these keys are rarely seen or used today.

Image of a sideswiper Morse key showing how it is able to use a side to side action
A sideswiper

The basic concept of the sideswiper Morse key is that it has two contacts, one either side of the central position. The lever can be moved from side to side to produce the dots and dashes.The key takes quite a bit of getting used to, and as it does not provide the same improvements in speed and ease of use as other later developments, few sideswiper keys are seen.

Semi-automatic mechanical keyer or "bug" key

Vibroplex and other forms of mechanical semi-automatic Morse key are still in widespread use. After using a straight Morse key, they take a little practice to get used to. Also it is necessary to be very aware of setting up the contacts so that a 1 : 1 mark space ratio is achieved on the dots and that when sending, the ratio between the dots and dashes is accurately maintained. It is very easy when using these keys to send Morse code that is not particularly easy to read. However when they are correctly set and being used well, they provide a good method of sending high speed Morse code.

A modern presentation Vibroplex semi-automatic mechanical bug key style of Morse key.
A modern version of the original Vibroplex Morse key

A further point to note is that these bug keys are not suitable for keying high voltages or currents, of for switching any loads that are inductive. The reason for this is that small sparks are created that soon burn the contacts and form pits on them. Also these keyers tend to create clicks as the make and break action is not particularly positive. Accordingly the key click filters on the transmitter should be checked to ensure they can accommodate this.

Although Vibroplex held the patent for mechanical bug keys for many years, they have now fallen out of patent and over the years a number of other manufacturers have made them - some Japanese and some from other areas. Today Vibroplex is still the main manufacture as demand has fallen as many people use one of the various forms of electronic keyers.

When using a mechanical bug key with a ham radio transmitter, care must be taken not to generate key clicks. As the dot mechanism does not make a particularly firm contact, the make and break actions are not always very clean and clicks can arise that will spread out from the main signal. There are two remedies for this. One is to employ a key click filter in the form of a low pass filter to smooth out the switching transients - modern transceivers normally have reasonably good filtering, but it is always best to check. The other precaution is a place a small amount of foam on the spring used for the actual dot contact. A little experimentation may be required.

Fully automatic electronic Morse keyers or "El-bugs"

With the advancement of electronics, fully automatic keyers that generated dots and dashes were eventually produced. Some of the earliest designs date from the 1940s, one even appeared in the April 1940 edition of QST, the magazine of the American Radio Relay League. Since then considerable developments have been made in terms of Morse keyer technology.

The technology for these keyers has been further enhanced and most are now able to store strings of letters or pre-set messages. In this way for ham radio contests, or other forms of operation, frequently used messages can be stored and sent quickly and accurately.

Nowadays, many ham radio transceivers include the electronic circuitry for the Morse keyer. All that is required is for the external contacts for the Morse paddle to be made to the transceiver. In view of this only the paddle is required, and as a result, fewer complete keyers are available and sold.

Iambic keyer

Iambic keyers are a further development of the basic electronic Morse keyer or el-bug.

A iambic keyer / electronic Morse keyer / el-bug showing the two paddles enabling it to be used in iambic or squeeze mode
Iambic keyer

In the iambic keyer, the paddle system used for basic mechanical and electronic keyers has been developed.

The iambic keyer system uses two paddles side by side to provide the "iambic" mode. Here if the left paddle is pushed to the right, a series of dots is made. If the right paddle is pushed to the left, a series of dashes is made. If the two are squeezed together dots and dashes are interspersed. Obviously the first paddle to be pushed in provides the first element of the Morse character. In other words to produce the letter 'C' (dah-dit-dah-dit), the dash paddle has to be pushed in slightly before the dot one.

The iambic keyer mode considerably helps with the sending of high speed Morse code.

In view of the squeeze action, these iambic keyers are sometimes called squeeze keys.

Morse paddles

As electronic technology developed, the electronic circuitry required in electronic keyers was incorporated within many ham radio transmitters or transceivers. This meant that only the mechanical Morse paddle was required externally.

As a result a variety of single Morse paddle and dual Morse paddle, iambic keys became available. By incorporating the electronic circuitry within a transmitter, no external power supplies were required for the Morse key, reducing it again to a mechanical assembly, albeit a precision made one.

These Morse paddles are widely available from different manufacturers enabling the user to select the one that suits best.

Morse keyboards and automatic Morse code generators

Today, there are many processor or computer driven Morse code generators. Morse keyboards can be very useful when wanting to generate long Morse transmissions. While these seem to be items that were a recent invention, it is surprising to learn that the first step in the automation for generating Morse code signals occurred as far back as 1902 when Charles Yetman received his patent for what he called a telegraphic transmitter. Unfortunately this idea was well ahead of its time, and the unit consisted of a typerwriter keyboard that converted the key depressions into Morse characters. The idea did not catch on because the unit was large and expensive. However it showed that it was possible to generate Morse code automatically.

Automatic generation of Morse code had to wait until home computers like the Apple II and the first IMB PCs became available in the early 1980s. With the further development of PCs and sound card technology, full packages became available that could not only send Morse but also decipher it as well. Although these Morse coder readers are not able to copy as well as the human mind under conditions where interference levels are very high, they are nevertheless able to provide good copy under many conditions.

Choice of Morse key

The choice of the best Morse key is often a difficult one. It is often dictated by the anticipated speeds that are likely to be sent, the transmitter and the preferences of the operator.

Straight keys are often useful for slower sending, and more relaxed contacts.

Most people tend to use paddles in association with the electronics in their transceiver. This enables swift end well spaced Morse to be sent quite easily.

Often ham radio DX-pedition or contest stations will use a paddle in association with a computer to generate some commonly used sequences.

In the end the choice of Morse key is dictated by preference, equipment and situation.



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