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The Keyall HV kit

May 2, 2018 - new circuit board, R2 eliminated

Keyall HV options

[Keyall HV parts picture - click for larger view ] The Keyall HV kit allows the owner of a keyer with a low voltage positive (NPN or n-channel MOSFET) keying transistor to drive the vacuum tube transmitters and transceivers of yesteryear. This unit will key negative voltage rigs (grid block keying) or positive voltage rigs (cathode keyed tube transmitters and conventional +13.8V powered solid state rigs). The output transistors and capacitor are rated at 1000 V and 3.1 A (3100 mA). The Keyall HV will normally key a single transmitter.

The Keyall HV kit is an update of the original Keyall kit.

05/02/2018: Note that the board is now silk screened, solder masked - aso R2, the 100k ohm resistor, has been eliminated

11/03/2015: NEW - a $14.00 version of the Keyall HV is now being offered with 500 volt (IRF820) transistors instead of the stock 1000 volt transistors (IRFBG30).

The Keyall HV circuit has been used for high power external amplifier keying by Gary, KD9SV.

W0VLZ provided this link to his experiences with the Keyall, thanks Niel.

September 30, 2017: A customer has encountered keying problems with a Heathkit DX-40 (cathode keyed rig), the problem was solved by removing R2, the 100k ohm resistor. This may lengthen the key down slightly (3 milliseconds?) - it's probably only needed IF the Keyall HV is used at higher current levels (175 mA and above ?). The customer reported that the DX-40 keying sounded OK on a shack receiver.

  • design is a MOSFET based solid state relay, SPST-NO single pole, single throw, normally open
  • high voltage output is optically isolated from the low voltage input
  • kit includes a circuit board and all board mounted components
  • just add your enclosure, in/out jacks and a battery holder
  • Size is 1.25 x 1.5 inches - fits into a candy tin with room to spare
  • Price (no printed documentation) is $15.50 + shipping/handling
  • add another $1.00 for a 6 pin socket for the PVI

  • Printed manuals available for an additional charge or save money by downloading (Right click/save target as) and printing the revised manual , schematic and hookup diagram (unchanged).

    For kits purchased before May 2019: manual , schematic and hookup diagram.

    Print out a Kit order form to figure your order manually
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    Keyall HV options
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    Downloadable files for the Keyall HV kit

    The Acrobat files of complex diagrams (like the schematic) may not view well on your computer screen - suggestion: use the magnifier to zoom in for better detail or print out the file.

    keyallhvsche2.pdf (123k) - an Acrobat file of the latest Keyall HV schematic

    keyallhv2a.pdf (54k) - an Acrobat file of the latest Keyall HV manual


    original doc files:

    keyallhv.pdf (54k) - an Acrobat file of the Keyall HV schematic

    keyallhvm.pdf (9k) - an Acrobat file of the Keyall HV manual

    keyallhvhu.pdf (87k) - an Acrobat file of the Keyall HV hookup diagram

    5msperdiv.JPG (1.1 Mb) - a JPG of the Keyall HV test fixture prototype rise/fall times

    The top trace is the Keyall HV output
    The bottom trace is the keyer input
    The graduations are 5 mS per division horizontally and 1 volt vertically.
    keyer speed is over 60 wpm

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