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Use keyer with Kenwood TS-440?

May 12th 2020, 07:23


Joined: Nov 11th 2015, 01:42
Total Topics: 0
Total Posts: 0
Has anyone had experience using a Kenwood TS-440S with a keyer? I would like to plug the Digikey K-1 output directly into the radio, but it does not seem possible.
May 12th 2020, 09:38


Super Moderator

Joined: Apr 4th 1998, 00:00
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Total Posts: 0

The TS-440 has a 1/4" phone jack for an external key. You can plug in a keyer into this jack. It is just above the power cable.

The may be an issue with pulling the key line low enough. Older keyers used bipolar keying transistors or were designed for grid block keying. What works is a HexFET like the IRF510 or IRF511. These FETs present a very low resistance when on, and should key the TS-440 just fine. But, these FETs weren't available until the 1980s.

Zak W1VT
ARRL Senior Lab Engineer

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