Curtis K5 Lil’ Bugger

Curtis K5 is a small keyer that utilizes the Curtis 8044B chip. Lil’ Bugger K5 was the last keyer produced by Curtis Electro Devices in 1982.

First of all, I would like to thank my friend Clancy N6FQQ for giving me his Curtis K5 Lil’ Bugger keyer.

Thanks to VE7CUU for offering me this Key

History of Curtis Keyer – Brad Mitchell, N8YG, wrote for the ARRL Web site in 2002

Mitchell wrote that Jack Curtis K6KU, when studying for his Amateur Extra ticket, “decided to get a feel for the requirements of the Extra Class test by undertaking a circuit design project. John built a keyer circuit and learned about digital electronics.” This keyer worked so well that Curtis’s ham friends told him he should market it. Curtis followed the advice, and in 1969, he placed an ad in “Ham Radio Magazine” announcing the Curtis Electronic Devices EK-38. The -38 and its follow-up, the -39, became so successful that Curtis quit his day job and formed Curtis Electro Devices.

Curtis had established a lot of contacts while working at a semiconductor manufacturing company in the 1960s. These paid off for him when he decided that a keyer circuit could be implemented on a chip. He started with two designs: The 8043 and the 8044. “The 8043 was designed as a completely custom integrated circuit in CMOS,” Mitchell wrote. “At the same time, International Microcircuits was looking for a chip in which to test their gate array technology. The first chip down the line was the 8044, produced for Curtis. The 8043 worked first try. It was limited to dit memory, and sold for $7.95 in quantities of 50 or more in 1973. The 8044 also worked right off the bat. It offered dah memory in addition and sold for $24.95 in 1975. The 8044M was introduced in 1980. M stood for meter. A meter could be hooked up to a pin of the 8044M to indicate sending speed.”

In 1981 Curtis added mode B keying characteristics to his keyers. Mode B simply added an extra dit or dah when the operator stopped sending, depending on which was sent last. If a dit was sent last, an extra dah would be sent. If a dah were sent last, a dit followed. Curtis added this feature to his 8044B. He introduced several keyers incorporating his new full-featured ICs. The first was the EK430 incorporating the 8043 chip. Curtis also introduced a fully integrated keyboard chip called the 8045. In June 1982, Curtis Electro Devices produced its last keyer, the Lil’ Bugger. Offered as the K5 or K5B, it incorporated the 8044 or the 8044B chip, respectively. Both models sold for $39.95 and were quite popular.

In spring of 1986, Curtis introduced the 8044ABM chip. It incorporated selectable A or B modes and the speed meter, becoming an industry standard. In the 1980s, however, microcontrollers were making serious headway and Curtis chips were no longer in demand. MFJ took over part of the line and Curtis Electro Devices ceased operations in April 2000.



  1. Dan

    Did you have problems with batteries powering the Curtis chips getting drained? The ARRL Handbook said that a power switch would not be necessary. My Vibroplex keyer had one of the chips in its triangular wood base. The mercury battery would not last until I provided a power switch for it. I also changed all the germanium diodes to silicon too. One or the other mods cured the problem. For this weekend’s FD, I used the keyer with a battery that has to be over 30 years old.

  2. Dan

    (this may be a duplication. Not sure my original post got thru)
    My 1982 Vibroplex keyer has a hollow wooden triangular base to accept the EK-1 circuit board with 8044. The mercury battery is the size of the 12V alkaline battery in a garage door fob. It would not last until I added a power switch and changed all the diodes to silicon. Then I never had to buy another battery. At FD this year I made 100 Q’s with this keyer. That mercury battery was at least 30 years old.

    I opted for the EK-1 keyer over the plainer 3-wire model because in 1982 most rigs didn’t come with a keyer. It’s not a great keyer. In terms of feel, either you love it or hate it. One feature was particularly dumb for owners of negative keyed tube rigs, i.e. my TS-520. You were supposed to reverse the connections in the plug to allow the driver transistor to key the negative bias. But this meant the keyer chassis was live. The screws holding the brass frame onto the wooden base protruded downward, and the rig would go into transmit if they touched any metal that was grounded. Vibroplex put on rubber pads to raise the base. But when I placed it on the top of my rig, the screws under the keyer could touch screwheads on my rig. So I put tape on the bottom of the keyer.

    Can you use the Curtis 8043/44 with an “A23” 12V alkaline battery? It’s the same size as the mercury battery in my EK-1. But the higher voltage may be unsafe even with a series resistor. Maybe you could pry one cell out of the A23 alkaline stack? OTOH the keyer seems to work at 6V so I could probably run it with 2 lithium cells.

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