ILER-DDS V2.1 VFO/DDS.
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with the frequency spotting of the dial and should NEVER be adjusted to compensate for the LO
(VFO) offset.
The ILER-DDS, when used as local oscillator (LO) for a receiver o transceiver, will be generating a
frequency which is the sum of the frequency that you may read on the LCD top line (it is the frequency
stored at the menu entry "Save Freq Ini") plus or minus the IF value, stored on the menu entry IF FREQ
(VFO=IF+RF, VFO=IF-RF o VFO=RF-IF).
When the ILER-DDS is used as RF generator (IF FREQ mode will be IF = 0) the generated frequency
will be the one shown on the display.
I will show several ways of doing this adjustment.
If you use the ILER-DDS as LO:
- Should you have access to a good frequency counter and you trust its calibration, or a good receiver
with enough dial resolution, you may check the theoretical frequency based on the display number and
the IF offset and mode. This method, though, will not allow you to compensate the frequency error
caused by the IF tolerances.
- If you are using the ILER-DDS for an SSB transceiver and you have access to a good receiver, tune it
to the frequency shown on the display and check your transmission on the receiver while you speak.
Adjust the calibration value, as it if were a Clarifier, until you get a perfect tuning and your voice sound
natural.
- A third option, similar to the previous one, is to do the adjustment "on the air" while listening to a station
of known frequency, tweaking the calibration until you get a perfect tuning.
If you are using the ILER-DDS as RF generator:
- Should you have access to a good frequency counter and you trust its calibration, just read the
frequency generated by the DDS and tweak the calibration until the counter reading and the LCD dial
match.
- In case you don't have a counter, you may use a good receiver.
Once you are done, make a quick push to exit. The adjustment will get stored and the ILER-DDS will
restart up normally.
Notes:
-This is a very precise adjustment, with a resolution of one Hz. If you listen on a receiver the tone change
is very slow. Please be patient to obtain a good calibration.
-Should you are going to use a receiver for the adjustment, you should be really sure of the dial precision
(do not use medium quality scanners or receivers with unknown precision).
VOLTS CAL:
Keep turning the encoder until you see “CAL VOLT” and make a quick push.
You will be adjusting the analog/digital conversion. You will have to know the
exact voltage of your power supply or battery. By turning the encoder you
will move the displayed value to the supply voltage. Use a good quality
multimeter for this measurement. After the adjustment a quick push will exit
from the configuration menu and the ILER-DDS will start-up normally.
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