Vectronics VEC-1220K - Manual (Page 27)

VEC-1220K/1230K/1240K/1280K Owner's Manual
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If you don't have access to a wattmeter, a standard 5 mm LED may be used to
give a rough indication of normal power output from the transmitter. When
using this test, however, the transmitter's antenna jack must be terminated with a
50-ohm dummy load. Connect the LED across the terminated antenna jack and
key the transmitter. The LED should illuminate brightly at normal power output
(do not attempt this test with higher power transmitters, or LED destruction may
result).
7. Key the transmitter and find its signal with your station receiver.
8. Monitor the CW note for severe chirp, 60-Hz ripple, or key clicks.
The presence of a "buzz" on the CW note may indicate poor power supply
filtering, or may simply mean there's a ground-loop in your test set-up that won't
affect your signal over the air. Obtain on-air reports to confirm hum or ripple
observations.
9. Key and tune the VXO capacitor. The transmit frequency should shift.
The amount of frequency shift you obtain will depend upon the band of
operation. On 20 meters, a tuning range of 7-kHz or more is possible. On 80
meters, as little as 1.5-2 kHz shift is typical due to the lower frequency of the
transmit crystal.
10. To test the receive side of the T/R switch, connect a 5-mm LED across J4
and key. If the LED doesn't illuminate when the transmitter is keyed, the
T/R switch is working and it should be safe to connect receivers to the
receiver jack. The transmitted signal should appear approximately -25 dBc
at the receiver jack.
This concludes the testing phase of construction. If your VEC QRP-CW
Transmitter Kit made the grade, you're ready to connect a receiver and an
antenna for some serious QRP operating! If it didn't pass, please refer to the "In
Case of Difficulty" section for some suggestions that may help you isolate and
cure the problem. If you purchased the VEC cabinet for your kit, now is a good
time to install your circuit board in it.
OPERATING INSTRUCTIONS
Connecting up the VEC QRP-CW Transmitter: