ILER-DDS V2.1 VFO/DDS.
Page 19
Take your time, as there is no "back-space". If you make a mistake you will have to repeat the process
since the beginnin.
IF FREQ:
Keep turning the encoder until you see “IF FREQ” and make a quick push.
This entry will be used to set the IF frequency.
Frequency is adjusted by the Hz, so all 8 positions are operative: for
instance an IF of 10 MHz must be programmed as 10000000 whereas 9
MHz will be 09000000.
The underlined cursor shows the position of the digit
to be programmed. Turn the encoder to select the desired digit at the position and make a quick push to
store the value and move to the next position. When you will get to the 8th position, the next push will
store the last digit and the ILER-DDS will jump with to a second submenu where the IF Mode will be
selected. There is no "back-space". If you make a mistake you will have to repeat the process since the
beginning.
The submenu for IF mode will cycle when the encoder is turned among the following options:
VFO = IF + RF ; VFO = IF - RF ; VFO = RF - IF ; IF = 0
(this will be used for an RF generator) ;
EXIT
To select one of the options make a quick push when the screen shows the one you want. The ILER-
DDS will restart normally with the new setting. If you don't want to change the program you may use the
“EXIT” entry.
These are the
nominal
IF configurations for the ILER-40, ILER-20 and ILER-17 transceivers:
BAND (RF)
LOWER LIMIT
UPPER LIMIT
IF FREQ
IF MODE
VFO/DDS OUT
ILER-40
7.000
7.300
4.915
VFO = IF + RF
11.915 - 12.215
ILER-20
14.000
14.350
3.276
VFO = RF - IF
10.724 - 11.074
ILER-17
18.068
18.168
3.276
VFO = RF - IF
14.792 -14.892
ILER-60
5.351.5
5.366.5
4.915
VFO = IF + RF
11.266.5 – 11266.5
Some configuration examples for typical bands and IF values:
BAND (RF)
LOWER LIMIT
UPPER LIMIT
IF FREQ
IF MODE
VFO/DDS OUT
3.500
3.500
3.800
9.000
VFO = IF + RF
12.500 - 12.800
7.000
7.000
7.300
9.000
VFO = IF - RF
2.000 - 1.700
*
RF GEN
0
40.000
--
IF=0
0 to 40 MHz
*
Notice that on this mode (VFO = IF - RF) when the RF frequency increases, the VFO/DDS generated
frequency should decrease, and vice versa.
FREQ CAL:
Keep turning the encoder until you see "CAL FREQ" and make a quick
push. On this entry it is possible to make a fine adjustment of the frequency
of the DDS in order to compensate for tolerances on the reference oscillator
or the IF parts, which may be of the order of several hundred Hz. The
adjustment margin goes from -2500 Hz to +2500 Hz. (If this margin is not
enough, it may be a sign that the programmed IF value is incorrect).
IMPORTANT: To "calibrate" the frequency of the dial, never adjust the BFO of the transceiver.
This is not the way to do it! Do not run the BFO adjustment, which has no relation whatsoever
I
F
F R E Q
0
4
9
1
3
5
0
0
F R E Q
C A L
0
7
1
5
0
0
0
0
+
0
H z
