Before finishing your kit you must decide what 35 to 40 khz span of frequencies you want to work. Or, you might have completed the kit and can't find the span of frequencies you desire.
It is best to leave C7 off until you have the transceiver fully functioning on transmit and receive. Studying the right column on Page 13 you will see that you should have a good carrier on transmit somewhere around 7.230 with T2 and T3 peaked and the tuning pot at the highest setting. If it is not, DO NOT proceed until you fix the problem. It could be the wrong number of turns on toroid L1 (you may need to remove a turn on L1 if the L.O. is too low), or improper capacitor in the C3, 4, 5, 6, 8, 9 position. Before proceeding the transceiver must be transmitting on around 7.230.
In the scan above, a 100 pf capacitor was installed in C7 and tuning knob was set in the middle. As you can see from the spectrum analyzer above, the VCO is sitting right on 3.065 which is exactly 4.000 mhz below desired frequency 7.065. Without C7 installed and tuning knob at highest setting there should be a carrier at around 3.230 khz.
From the above, you can troubleshoot the VCO without transmitting by tuning your "big rig" to just below the 80 meter band to find your VCO frequency. A small wire for an antenna in your "big rig" loosely placed near the VCO which is around L1 toroid will help you hear the signal. This way you won't have to be transmitting all the time when troubleshooting or selecting the C7 capacitor. With an antenna connected you should tweak T1 for maximum noise or a maximum carrier from a received signal.
When selecting the C7 capacitor DO NOT solder it in place yet. Form the leads on each C7 capacitor in a bowleg as shown below. This will make good contact and keeps the capacitor from falling through board.
Then place in the C7 holes in circuitboard. It will make sufficient connections to tune the local oscillator so you can select the correct value before soldering.
Once you're satisfied you have the correct span of frequencies you can solder C7 in place. Peak T2 and T3 into a dummy load and adjust R24 for output power just under 1.95 watts or so. Try not to exceed 2.1 watts or you'll hear some RF getting into other parts of the transceiver and you'll hear a raspy sidetone. Do not transmit without a load connected.
Some of you might want to put a switch in to change C7 to select different areas of the 40 meter band to operate. This can be easily done since one end of C7 is ground. You may have to adjust C7 values since you are adding stray capacitance to the VCO tank circuit. If not, the published frequencies on Page 13 will be slightly off.