TX board assembly:
Unplug the SSB board fromthe K1 RF board and complete its assembly with both TX and RX parts (see complete list for all missing parts).
When ready, plug-in it back on the K1 RF board.
TX alignment
Select K1 filter 1 or 3 then go in TX mode (see below) then adjust Potentiometer V4 for maximum carrier suppression (you can use a Scope or
another Receiver)
In order to access the microphone jack J1 you need to drill a hole into the left side panel at the corresponding position of J1.
It is also possible to add a microphone jack on the back panel of your K1 and run a shielded cable from this jack to the K1 SSB board. For this
purpose an additional 2-pin connector (in parallel to the jack J1) has been provided on the SSB board.
Plug the microphone into J1 (or the back panel jack, if preferred) then adjust the potentiometer V3 for a suitable mike sensitivity and SSB
modulation. I suggest you to prefer an Electrete mike; I used a low cost PC Mike for sound card. The connector is compatible (3.5 mm Jack).
The BFO settings, must be revised for TX operation too:
Set filter 3 to 200 Hz (FL3) then adjust C12 for 4916.850 KHz (+/-50 Hz)for USB mod. (frequency test point, pin 7 -U3 , verify Vpp > 200 mV)
Set filter 1 to 850 Hz (FL1) then adjust 4913.900 KHz (+/-50 Hz)for LSB mod. (frequency test point, pin 7 -U3 , verify Vpp > 200 mV)
Adjust C34 (filter FL2) for the best CW note (about 4913.500 KHz)
Set once again filter 1 and adjust again C12 for 4916.850 KHz.
Switch on TX and verify the TX BFO offset setting (about 4914.1 KHz) (frequency test point, pin7 -U8 of the K1 RF board)
This CW offset set-up can be made as described at the page 47 of the K1 manual, or by using an AF spectrum analyser (many AF spectrum
analysers are available on line, they use the PC Sound blaster)
To perform this test you need to install the jumper parallel to the zener Z1 and close the S2 switch (on the K1 board) on the test position.
The SSB signal can be verified with a scope at the P6 connector as following (not strictly necessary ):
•Set LSB (FL1) or USB (FL3): Then set V4 for minimum carrier level without modulation (alternatively you can use an additional receiver to
minimise the suppressed carrier)
•The SSB signal at 4915 kHz can be observed at this point (>700 mV during modulation)
The SSB quality can be alsoverified on the K1 speaker:
•place a short circuit by the supplied Jumper (P8) in parallel to the zener Z1.
•Turn the switch S2, (bottom of the K1 RF board) in the Test position.
•Verify the SSB modulation on the K1 speaker (I suggest you to use head phones in order to avoid a noisy audio feedback).
•Remember to turn S2 back to the Operation position and to remove the jumper on Z1 at the end of this test.
