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Morse Code

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Morse Code is often called CW, meaning an interrupted Carrier Wave.  It is a very slow mode to transfer information.  The rate of information transfer could be in the order of 10 or 40 words per minute.  It usually has a much greater range than speech and requires a smaller bandwidth.

The "cocktail party effect" means that people can be in a noisy room with many people speaking at the same time, but can still concentrate on the one conversation they are having.  The human brain can often filter out unwanted conversations.  It may depend greatly on how loud the wanted voices are, compared with the unwanted voices.

Receiving Morse Code is similar.  An expert can listen to a channel which has several radio transmissions all mixed together.  By concentrating on the one required, that Morse Code signal can be understood.  It probably depends on the signal to noise ratio i.e. how much stronger the wanted signal is, compared with the unwanted signals heard at the same time.

Some Radio Amateurs (it takes all sorts) send and receive Morse Code using their computers.  Morse was the original data mode, but other codes are much more suited to computer use.

Low Power Across 3,160 miles

On 26 Jun 2002, a record contact took place using slightly ancient low power radio equipment and Morse Code. The conversation took place between Gateshead, Tyne & Wear, and Belmont, Massachusetts.  Keith Watt, callsign G4MSF, was at the UK end.  He is also mentioned in this website's APRS page, as he runs an Internet Gateway.   Chuck Counselman, callsign W1HIS, was at the USA end.

Keith used 1 Watt of power.  Chuck used 10 Watts of power.  As if that wasn't impressive enough, they both used ex-army World War 2 equipment.  Keith used a Wireless Set No. 22 and Chuck used a Wireless Set No. 19.  The contact took place on the 7 MHz amateur radio band.

Modern rigs are frequency stable, can change frequency in 100 Hz increments and have adjustable receiver bandwidths.  The 19 Set and 22 Set stability was somewhat wanting.  The transmit frequency drifted all over the place.  As the receiver bandwidth was as wide as a barn door and allowed you to hear many signals at the same time, it sort of compensated for the transmitter drift.

The 19 and 22 Sets were designed for use in tanks and armoured vehicles for short range communication over a few miles.  The frequency coverage was 2 to 8 MHz and the modes available were CW, MCW (both Morse Code) and AM (Voice).  The 19 Set also had a VHF facility on 220 MHz.  I used to own a 19 Set in 1965, but I'm not sure about the facilities of the 22 Set.

The photographs below show Chuck with his 19 Set and Keith with his 22 Set.

 
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Page updated on 09 January 2017

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