Press MOD to select USB. Adjust VC1 until the reading is 9001.199 or 9001.200, 2.8kHz
apart from LSB. Maybe your reading is 9001.998, or 9001.201. The result is good enough.
Select LSB. If the frequency is changed a little, trim L2 again to meet the requirement.
Questions from the users:
Question 1
-- I adjusted VC1 but I cannot reach 9001.200MHz. How to solve this
problem?
Two reasons to cause this problem:
(1) The red clip is connected to the test point without a resistor. The input of the frequency
counter might affect the BFO frequency. Or the resistor value is too small. Try to use a
greater value, say 1k or 2.2k, even 4.7k if you can take a stable reading.
(2) The crystal group is different. Try to use 8998.000 as LSB, 9000.800 as USB. In this
case the IF setting of DDS Unit is -2000, not -1600.
Question 2
-- I had calibrated the BFO frequency to 8998.400 at LSB mode. However,
when I turned the rig on next time, the frequency was not 8998.400; it was 8998.700 -
8998.900. Anything wrong with my kit?
Do not worry. About 10 - 20 minutes the frequency will be 8998.400 again. According to
the experiment, it takes about 15 minutes for the BFO to stablize at the ambient
temperature of 30
°
C. The BFO crystal needs warming-up time. Let TJ2B work for 15 - 20
minutes before Calibrating the BFO frequency.
Question 3
-- I have calibrated the DDS unit and BFO, but the kit still has 30 Hz error.
Summary of Contents for TJ2B
Page 3: ...Cables for internal connections Components package...
Page 5: ...Pre assembled Miniature Transformers Packed in a separate plastic bag Brass Stand Off Parts...
Page 10: ...How to insert the LCD Cable Never bend the cable end soldered to the LCD...
Page 12: ...Now solder the 7 wire cable...
Page 35: ...50 ohm cable and MIC cable are connected How the cable is soldered...
