4SQRP Bayou Jumper 40 Meter CW Transceiver, Assembly & Instruction Manual

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revised 3 Feb 2021 Bayou Jumper revB Assembly Manual page 43 of 46
J.
The NA1MH Soup’er Up’er Accessory
David Martin, NA1MH, designed an add-on for the
Bayou Jumper that provides a sidetone, a fine
tuning control, and the NMØS HI-PER-MITE
audio
filter.
This accessory is not currently being kitted and supplied
by Four State QRP Group, but “previously owned”
units are occasionally offered on various QRP forums,
and documentation is available for download.
A small PC board is attached to standoffs
under one corner of the main board and is
connected to the main board using the
connection points described in
Appendix I ,
above. No trace cutting is required.
Provisions for mounting a fine tuning
potentiometer and filter IN/OUT switch have
already been made on the revA circuit board
(see
Appendix F ) and the underside of the
front panel is marked to locate the holes to
be drilled to accommodate the extra
controls.
K. Using a keyer
During transmit key-down intervals the
keying current of the Bayou Jumper is
about 750 mA, which will exceed the
capability of many keyer output circuits. A
robust PNP power transistor, a MOSFET
power switch, or a relay, are called for.
In the special case of the Four State QRP
Group’s
EZ-Keyer , the supplied BS170
output transistor could be replaced with a
heftier MOSFET such as the IRF510.
Any one of the circuits at right, suggested
by NMØS, could be used to interface
between a conventional keyer and the
Bayou Jumper.
NA1MH photo of beta version
WØEB photo