Youkits TJ5A SSB CW HF TRANSCEIVER
Guide to Alignment of TJ5A
TJ5A
is a high-performance portable multi-band SSB/CW transceiver, used with DDS as
LO, offering wide frequency coverage and fine tuning rate. The Doubly Balanced Diode
Ring Mixer and high-performance fast AGC make strong signal handling capability
possible. With the high-performance IF AMP,
TJ5A
features extremely low background
noise reception.
TJ5A
is a fully tested, almost ready-to-use kit. What you are required to do is trim the BFO,
calibrate DDS clock, and set up IF and USB settings.
IMPORTANT
. Before calibrating BFO or DDS, please warm up both the frequency
counter and TJ5A for 20 minutes for more accurate result.
BFO has been calibrated without the warming-up step before shipping. If you do not have
a frequency counter, you may ignore this step. However, there would be a frequency
tolerance of around 50Hz.
Now, remove the related screws and open the upper cover of TJ5A.
BFO Calibration
Before calibrating the BFO, first make sure that the RIT control is at the zero position.
Follow the following steps.
1) Set PWR knob to the lowest level.
2) Use a digital multi-meter to measure the voltage between the center pin of CN5 and
GND (the screws on the four corners of the main board can be regarded as GND).
3) Press PTT, and observe the reading. Take down the reading (around 4.36V). Now
