EA3GCY ILER-DDS User manual

ILER-DDS V2.1 VFO/DDS. Page 1
ILER-DDS V2.1
Assembly manual
Last review: February 1, 2018
[email protected]
Latest updates and news: www.ea3gcy.com.
Thanks for purchasing the “ILER-DDS” VFO kit
Enjoy building QRP ! 73 Javier Solans, ea3gcy

ILER-DDS V2.1 VFO/DDS. Page 2
TABLE OF CONTENTS
TOC…............………………………………………………………………………………………. 2
INTRODUCTION……………………………………………………………………………………. 3
SPECIFICATIONS.….………………..…………………………………………………………….. 3
PART ONE: ASSEMBLY AND INSTALLATION……………………………………………….. 4
TIPS FOR FIRST TIME BUILDERS………………………………………....……………………. 4
PARTS LIST..………………..………………………………………………………..…………….. 6
ASSEMBLY..…………………….………………………………………………………………….. 8
INSTALLATION…………..……………….…..……………………………………....................... 9
DIGITAL NOISE………………….…………..………………………………………………......... 12
ILER-DDS WIRING………...……………………………………………………………………... 13
SCHEMATICS……………………………………………………………..…………………….... 13
PART TWO: PROGRAMMING AND USING THE VFO/DDS ..….....…………………….... 15
FACTORY CONFIGURATION……………….……………………………………………...…. 15
USING THE ILER-DDS……………...…………….……………………………………………… 15
USER MENUS………….………….…………….…………………………………..…………… 16
MENU FLOWCHART………………..…….……………………………………………….…… 17
CONFIGURATION………………..……………….……………………………………………… 18
ANNEXES………..………………..……………….……………………………………………… 22
IF YOUR KIT DOES NOT WORK AFTER FINAL ASSEMBLY …………………..………… 24
LIMITED WARRANTY ………………………..….……………………………………………… 25
OUTPUT SIGNAL IMAGES…………..…….…………………………………………………… 26

ILER-DDS V2.1 VFO/DDS. Page 3
INTRODUCTION
The ILER-DDS VFO is a RF generator based on the Analog Devices AD9850 DDS chip
(www.analog.com). At present, the direct digital synthesis (DDS) is an excellent solution for the LO on
single-band and multiband amateur equipment, at a very moderate cost. Due to the very high frequency
reference (125 MHz), the ILER-DDS offers a very clean signal when working at relatively low frequencies
as 11, 20 or even 30 MHz. (< 25% of the reference frequency). If you want to delve deeper into the
theory of DDS we advice you to read the abundant internet literature. The use of a "sandwich" single
block mechanical configuration and a single encoder with a built-in push-button to control the operation
makes this VFO/DDS an extremely versatile "block" easy to integrate in many projects for amateur rigs.
SPECIFICATIONS
Universal VFO for all ILER, MFT, EGV transceivers and similar projects.
S-METER level indicator with digit from S-0 to S9+ and 10-level graphical bar.
S-METER voltage input from 0 to 5V direct or inverted, with independent adjustment of each level.
Dual VFO A/B
RIT / SPLIT function without limit
Configurable Tuning Steps: selected ones or all steps (from 10 Hz to 10 MHz).
Programmable IF Offset. IF=RF+VFO, IF=RF-VFO, IF=VFO-RF, IF = 0 (RF generator).
Programmable upper and lower band limit.
Fine calibration of the frequency reference by software (up to 1 Hz accuracy).
Voltmeter display with 0.1 V accuracy (0.01 V calibration).
Auxiliary I/O pins for expansion.
2 x SINUSOIDAL WAVE OUTPUT.
2 x SQUARE WAVE OUTPUT.
LOW SPURIOUS. TX and RX mixers spectrum is equal to or better than a VXO one.
DDS AD9850BRS integrated circuit.
Reference clock: 125 MHz.
Signal output level at 200 ohms: 300mVpp 35MHz // 800mVpp 20MHz
User programmable “Welcome message”: callsign or name.
LOCK function for push button and encoder.
Automatic record of last used frequency or current frequency.
2 Line x 8 character LCD with AUTO-ON-OFF configurable backlight.
Power supply: 7.5-14 V about 90-100mA (no backlight)
Outboard encoder for a more versatile mechanical configuration.
Small size "sandwich" module, easy to fix with screws or glue.
Total space used: 51 x 36 x 40 mm W-H-L (with soldered LCD 35 mm L). LCD window size 29 x 19 mm.
Soft touch non-stop rotary encoder (like commercial equipment).
24 steps per revolution rotation encoder (maximum speed 36 step/s).
All operations are executed with the encoder and pushbutton.
Simple, direct, and immediate configuration through menus.
All settings are stored in EEPROM (1 million write/read cycles (minimum) and 100-year).
PIC18F2525-I/SP microcontroller 20 MHz clock.

ILER-DDS V2.1 VFO/DDS. Page 4
PART ONE:
ASSEMBLY AND INSTALLATION
PLEASE READ THOROUGHLY ALL THE MANUAL AT
LEAST ONCE BEFORE ANY WORK IS DONE.
TIPS FOR FIRST TIME BUILDERS
Tools required:
- Small tipped soldering iron of about 25-30 W rating, small side cutters, wire strippers, pliers, long nosed
pliers, sharp hobby knife, and screw driver for the M3 bolt.
- You will also need good lighting and a magnifying glass to read the fine print on some parts.
Instrumentation required:
- Multimeter. Frequency Counter or calibrated HF receiver.
Soldering:
There are two important things which need to be done to ensure the successful operation of a kit: one is
to put the right part into the proper place on the board; the other is good soldering.
To properly solder you must use the correct type of iron and the right quality of solder. Use a small tipped
soldering iron whose bit is short and pointed at the end. The iron should be about 25-30 W (if it is not
thermostatically controlled). Only use multicored solder for electronics. NEVER use any extra flux. You
should hold the hot iron in contact with both the board and the part lead for about two seconds to heat
them up. Then, keeping the iron in place, touch the solder onto the junction of lead and track and wait
about two seconds or so until the solder flows along the lead and track to form a good joint. Now remove
the iron. The iron should have been in contact with the part and circuit track for a total time of about 4
seconds. It is a good idea to drag the tip of the iron up the component lead as you remove it from the
joint, this helps to pull any excess solder up with it and enables good flow along the component lead.

ILER-DDS V2.1 VFO/DDS. Page 5
Finding the right part:
IC’s
The board outline for ICs has a “U” notch on one end. This indicates the pin 1 end of the IC. There is
also a notch on one end of the sockets. This end goes over the “U” notch outline on the board. ICs have
usually pin 1 marked with a round dimple or dot. This end of IC will go towards the notch on the socket or
“U” on the outline.
Electrolytic capacitors:
These must be installed with the correct polarity. The positive (+) lead is always the long lead. The
negative (-) lead is marked by a stripe on the body of the capacitor can. Make sure the plus end of the
cap goes toward the hole labeled with the (+).
Transistors and diodes:
The transistors have the silhouette printed on the board. The diodes must be placed in the correct
polarity position, they have a color band on their body that must match the printed drawing on the board.

ILER-DDS V2.1 VFO/DDS. Page 6
PARTS LIST
Resistors
Checked
Ref.
Value
Ident./Comment
Circuit section
R1
10K
brown-black-orange
MCLR uC pin
R2
10K
brown-black-orange
ADC divider
R3
4K7
yellow-violet-red
ADC divider
R4
--
502 Adjustable
Contrast (1)
R5
--
See Note 2
Backlight limiter (2)
Rx-Ry
0
1/16W 0ohm. Factory soldered
PCB links
Capacitors
Checked
Ref.
Value
Ident./Comment
Circuit section
C1
100n
104 or 0.1
Power
C2
10uF
10uf 25V or 35V (elec)
Power
C3
100n
104 or 0.1
Power
C4
18p
SMD Factory soldered
Uc
C5
18p
SMD Factory soldered
uC
C6
100n
104 or 0.1
uC
C7
100n
104 or 0.1
uC
C8
10uF
10uf 25V or 35V (elec)
Power
100n
100n
104 or 0.1
On encoder terminals
100n
100n
104 or 0.1
On encoder terminals
Semiconductors, Crystal, Inductor, Encoder, Modules
Checked
Ref.
Value
Ident./Comment
Circuit section
IC1
7805
7805 5V regulator
Regulator
IC2
18F2525-I/SP
Microcontroller
Controller
IC3
MCP1825S33
MCP1825S33 3.3V regulator
Regulator
X1
20MHz.
20MHz cristal
uC clock
L1
100uH
SMD Factory soldered
uC +V
Encoder
Bourns Encoder PEC16
Rotary Encoder/Switch
Encoder/Switch
LCD 8x2
LCD 8x2
LCD Display 8x2 (backlight)
Display
AD9850
AD9850 HC-SR08
DDS module
DDS
Hardware
Checked
Ref.
Value/Type
Ident./Comment
Circuit section
IC2 socket
28 pins IC socket
uC
Pins strip
Pins for connections
--
Connections
Pin strip sockets
Cut with various measures.
--
Connections
Heatsink for IC2
Heatsink for IC2
--
Heatsink
M3x10 screw
Screw for IC1 heatsink
--
Heatsink
M3 nut
M3 nut for M3x10 screw
--
Heatsink

ILER-DDS V2.1 VFO/DDS. Page 7
Note 1. R4
R4 is adjusted to obtain the best contrast of the LCD.
Note 2. R5 values
Your kit may have three types of similar LCD.
R5 is different depending on the type of LCD. All resistors are included in the kit, but only need to be used
according to the following table:
LCD Type
R5 (Backlight)
GREEN 0802A (Ver1.0)
10 Ω brown-black-black
BLUE RT0802A
47 Ω yellow-violet-black
BLUE LCM0802C (V1.0)
47 Ω yellow-violet-black
You can vary slightly the R5 value.
< R5 (less): increases backlight (R5 can never be 0 Ω).
If you want the maximum level of backlight you can connect the pin 15 of the LCD directly to 5V, but note that you
can increase the total consumption by about 20mA.

ILER-DDS V2.1 VFO/DDS. Page 8
ASSEMBLY
As many modern kits, the ILER-DDS is designed to be easily assembled by medium-experience
builders. SMD components are already installed and there are no hard-to-install parts on the kit.
It is advisable that you inventory all parts to make sure everything is available and ready for assembly.
Each builder may have his/her own way of organizing parts, but if you do not, you might try using a block
of Styrofoam packing material. Parts may be sorted by type and size (ohms, microfarads etc).

ILER-DDS V2.1 VFO/DDS. Page 9
RECOMMENDED ASSEMBLY SEQUENCE
I strongly recommend that you install the parts in the following order:

1. Resistors. All resistors are placed vertically. R4 is an adjustable resistor, insert it as shown in the
picture.
2. Capacitors. C2 and C8 are electrolytic capacitors, the longer terminal is positive. There is a "+"
printed on the PCB.
3. Crystal. Open its legs carefully and insert it into the PCB.
4. IC socket for IC2. Note that the "u" mark on one end must match that marked on the board
silkscreen. Ensure that it lies flat on the board.
5. Male and female terminal strips. Ensure that they are straight and flat to the PCB. There are four
female socket strips (two of 8 pin to be soldered to the LCD, and two of 10 pin for AD9850
module). In order not to be mistaken, observe the photographs carefully.
6. Voltage regulator. Place the 7805 IC1 and MCP1825S IC3 with its lettering facing the board.
Place to IC1 the small heatsink included with the kit, with the "U" facing outwards (see the cover
photo).
7. IC2. Insert the PIC18F2525-I/SP microcontroller into its socket..
8. LCD and DDS module. Insert the LCD andAD9850 DDS module into their respective sockets.
INSTALLATION
PIN FUNCTION
Marking
Function
uC bit
1
+12V
+12V
2
GND
GND
3
ENCODER_A
RB5
4
ENCODER_B
RB4
5
PULSADOR
RB3
6
AUX
RB2
7
AUX
RB1
8
TX INPUT (RIT) to GND on TX
RB0
9
AUX
RA4
10
S-METER INPUT
RA5
11
SINE WAVE OUTPUT B (fromAD9850 module no LPF)
OUTB
12
GND
GND
13
SINE WAVE OUTPUT A (AD9850 module LPF built in)
OUTA
14
SQUARE WAVE OUTPUT B
SQRB
15
GND
GND
16
SQUARE WAVE OUTPUT A
SQRA

ILER-DDS V2.1 VFO/DDS. Page 10
Mechanical Installation
Important: Do not rush to make the mechanical installation. It is highly recommended that you
calmly study every possible way to place the DDS assembly block in your rig.
There are some wiring requirements that should be taken into consideration (see "ILER-DDS
Wiring"). Take care when planning the configuration most suitable for your application.
As you can see, the ILER-DDS block is designed to be easily incorporated into any existing rig, being
receivers, transceivers or as a general purpose laboratory RF generator.
Without doubt, there are many ways of implementing the integration of the ILER-DDS on your project.
Mechanically, there are two ways to attach the ILER-DDS block: with screws or with glue. I recommend
using "contact adhesive" on the LCD frame and the box front panel. A thin "line" of glue around the LCD
frame is sufficient. This is an extremely simple and safe method, and provides very good aesthetic
results. If necessary, you can always remove the LCD and clean the glue residue.
Do not use hard to remove adhesives such as cyanoacrylate, epoxy, etc.
In the pictures below, you can see a DDS block installation next to an ILER transceiver. The DDS is
attached with glue. As the LCD is fixed to the panel the other two modules (control board and AD9850
module) can be unplugged when required.

If the space available for the module integration is a bit short the depth of the
sandwich may be reduced by 5-7 mm by directly soldering the LCD to the board,
instead of using male and female headers. Please notice that if board removal is
needed in the future, you will have to unsolder all pins from the LCD or the board.
Note: The routing and placing of the ILER-DDS wiring may change the "digital noise" perceived (see
"Digital Noise"). For example the supply negative wire; the connection may be done through the shield of
the OUT coaxial cable. If noise is objectionable you will have to proceed with a trial and error denoising
process (see "ILER-DDS wiring").

ILER-DDS V2.1 VFO/DDS. Page 11
ILER Transceivers wiring.
If you have placed the VXO Components.
You will have to cut or lift one leg of L7 to remove the
supply to the VXO. It is not required to remove any
part from the VXO
It is possible to use either the VXO or the DDS?
May I work SOTA or backpack with the VXO and with the DDS at home?
Of course you do! You may have both and select one as needed.
This is probably the only amateur transceiver which may be configured to work this way. Slick!
With its low power VXO it will be possible to operate on the field or up the summits with a small battery
on your backpack. And with the DDS and its backlighted LCD display, a bit higher on consumption, you
will be able to operate on your car or at home.
It is simple:
Build your ILER complete, including the VXO and adjust it as per
the manual. You will have to place the ILER on a box with a dual
tuning system: the Polyvaricon for the VXO and the encoder for
the DDS.
Then, a DPDT switch must be used to route the supply for the DDS
on one of the circuits, and to connect L7 with the pad where it was
connected previously (VXO supply).

ILER-DDS V2.1 VFO/DDS. Page 12
DIGITAL NOISE
Noise coming from digital circuits on a radio receptor may be considered as normal when they are of low
level and the listening comfort and quality is not affected.
There are two types of noise: DDS generated spurs and noise from the digital control and display.
The design used on the ILER-DDS guarantees a low spur level when compared with other amateur
products of similar price. In all ILER versions the heterodyne purity is very high either in Rx or Tx. Due to
the filtering used little spurs are generated which may be noticed in reception, and also in transmission.
All tests carried out with our ILER-DDS prototypes with ILER transceivers have been highly
satisfactory.
LCD noise
LCDs are known to be a source of noise. Sometimes one may thing the noises are coming from the RF
generator but they are coming from the display. They may be recognized as they shift in frequency,
especially after a cold start-up. Should you perceive a background noise on your transceiver without any
antenna connected, and the noise changes when you touch or push the LCD, this is an LCD noise.
Encoder noise and other switching/digital noises.
The second, very common source of internal noises on a receiver is the switching of internal signals,
multiplexing, etc, or external signals, such as the ones from the encoder.
When you install the encoder, please remember to place a pair of 100nF capacitors on the encoder
terminals.
If you do a careful and tidy wiring of the ILER-DDS, we are sure that you will get excellent results.
Note:
EA3GCY can’t guarantee the result of fitting an ILER-DDS with receiver or transmitter kits others than
the ones from ea3gcy. The different combination of IF-RF, signal levels, impedances, etc. may let to
unpredictable results. You should know the details of your particular setup and enough expertise to
evaluate the suitability of the ILER-DDS for your purposes.

ILER-DDS V2.1 VFO/DDS. Page 13
ILER-DDS WIRING
The wiring is very simple but is important how you do it.
We don't want it to just work...... it should work PERFECTLY!
The position and wiring of the ILER-DDS will strongly affect the reception of noises in the receiver (see
"Digital noises").
Some advices to be taken into account:
For the output signal use good quality, fine coaxial cable (ej. RG-174).
Place the encoder as close as possible to the ILER-DDS block. If it is far away, and wires go by
or over the transceiver circuit may introduce switching noises whenever the encoder is used.
Even the supply wires to the connector or the ON-OFF switch may affect the nose level. Try with
only one wire, the positive one, as the negative will be routed through the coax shield.
It is not advisable to wire the LCD. The LCD should be sandwiched with the control board!
By the way: Do not forget to place two 100 nF capacitors directly between the encoder pins!
If need be, you will have to make changes on the wire routing or the wire type; it will be a "trial and error"
procedure.
Sometimes low level noises detected may disappear when the antenna is connected, and do not
affect adversely the reception. In that case: you don't have to fight them!
By following the previous advices, the wiring of the ILER-DDS is very simple. Please check the drawing:
The wiring described is from the back of both the encoder and the control board.
Your ILER-DDS kit can incorporate two types of rotary encoder. The two models are the same but have
their terminals positioned differently. Type A has the encoder terminals on top and the "push-switch" are
below. The type B has all the above, the encoder terminals are shorter and the switch are longer.

ILER-DDS V2.1 VFO/DDS. Page 14
Please notice that none of the two models the "common"
terminal is central. It is to the right.
Solder two 100 nF capacitors directly to the encoder pins
(between active pins and ground).
SCHEMATICS


ILER-DDS V2.1 VFO/DDS. Page 15
PART TWO:
PROGRAMMING AND USING
THE VFO/DDS
FACTORY CONFIGURATION
The ILER-DDS is configurated to work with the ILER-40, with the following parameters:
LOWER LIMIT:07.000 (Band lower limit: 7.000 MHz).
UPPER LIMIT: 07.300 (Band upper limit: 7.300 MHz).
YOUR CALL ?: CALL ON: EA3GCY
IF FREQ: IF = 04913500 Mode: VFO = RF + FI ( for ILE-40)
IF is 4.913500 MHz and the output mode from the VFO/DDS is 7.000000 MHz + 4.913500 MHz
Please notice that the IF real offset is lower than the nominal frequency of the IF filter crystals (4.915.8 MHz).
CAL FREQ: +150 Hz (you will have to adjust it to compensate for tolerances)
CAL VOLT: Calibrated. The measuring error may be up to +/-10 %
You will have to adjust it, as each kit may be different due to the resistors used at the divider placed at the input of
the ADC conversor (R2 and R3)
S-METER CAL: Calibrated. (for ILER-40)
S-METER MODE: Reversed.
VFO A/B: VFO-A
RIT ON/OFF: OFF
CHANGE STEPS:1 kHz - 100 Hz.
S-METER or VOLTS: Volts
SET INI FREQS: Current ones (fixed frequencies are stored in VFO-A and in VFO-B)
LCD BACKLIGHT: ON (always lit)
LOCK:Unlock
USING THE ILER-DDS
It is very simple. Once programmed, its use is highly intuitive.
Dial tuning and step change:
By turning right or left the rotary encoder the frequency respectively
increases or decreases by the current "step".
This is marked by an underline on the digit. For instance, the example shows the underline digit as the
kHz units. Every step will move the frequency one kHz up or down. If the underline will be placed on the
100 Hz digit, the steps will be of 100 Hz each.
A quick push on the encoder will change the position of the underline among the preselected "CHANGE
STEPS”.
The letter A in the second line means that it is in the VFO-A
7
1
5
0
.
0
0
A
1
2
.
5
V

ILER-DDS V2.1 VFO/DDS. Page 16
User Menus
You may access the menus by pushing and holding the encoder pushbutton for more than 1 second.
Then, turning the encoder will go through the user menus. One of the options is “EXIT” to exit without
change. Please consult the cyclic sequence of the menu flowchart on next page.
The access to the more frequently used functions is easy.
100 kHz steps:
This may be used to move rapidly throughout the band. Push the encoder
for more than 1 second. “100 kHz STEP” will appear on the screen. A quick
push on the encoder will bring you back to the frequency dial with 100 kHz
steps. Once you are on the place of the dial you want, another quick push will bring you back to the
normal tuning steps.
VFO A/B:
Switch between VFO-A and VFO-B. Press the button and you will return to
the dial screen, if before it was in the VFO-A, the VFO-B will appear and
vice-versa. The letter of the current VFO appears in the first box of line 2 of
the screen.
RIT ON/OFF:
Enables or disables the RIT function. Press to toggle between RIT ON and OFF. When the RIT is
activated, the symbols = ↑ ↓ indicate whether the frequency is equal, has risen, or has fallen with respect
to the previous frequency.
Note: If the TX signal of the transceiver is not connected to the DDS, then the RIT will not act (see the
connection table and theAnnex "Connecting the RIT input").
CHANGE STEPS:
There are five fixed sequences of steps available for selection:
1K-100H-20H ; 1K-100H ; 100H-20H ; 10K-1K-100H ; ALL STEPS
Turn the encoder until “CHANGE STEPS” appears and make a quick push.
By turning the encoder you will enter a submenu to select with the encoder the step sequence needed. A
quick push on the encoder will bring you back with the new sequence active.
Note: The “ALL STEPS” option is meant to be used when the ILER-DDS is used as RF generator.
S-METER o VOLTS:
This screen allows switching between the display of the Voltmeter or the S-
METER. If you want to use the S-METER, see the section "S-METER CAL".
SET INI FREQS:
In this menu chosen to save the current frequencies as initial frequencies
each time the ILER-DDS is started or automatically save the last frequency
before turning off the ILER-DDS. When "SET INI FREQS" appears, press
the button and moving the encoder you can select between "CURRENT ONES" (saves the current
frequencies as start frequencies) or "AUTO" (it will save as the start frequencies the last frequencies
where it was before switching off) .
1
0
0
k
H
z
S
T
E
P
V
F
O
A
/
B
C
H
A
N
G
E
S
T
E
P
S
S
-
M
E
T
E
R
o
r
V
O
L
T
S
S
E
T
I
N
I
F
R
E
Q
S

ILER-DDS V2.1 VFO/DDS. Page 17
Note: this function stores the VFO-A and VFO-B frequencies.
LCD BACKLIGHT:
The LCD backlight mode of operation may be selected with this menu entry.
Push the encoder for more than 1 second, turn the encoder until “LCD
BACK LIGHT” appears and make a quick push. By turning the encoder you
will cycle between “AUTO” (backlight will automagically turn off after 10 seconds of encoder or
pushbutton inactivity), “ON” (LCD always lit) or “OFF” (LCD always off). A quick push on the encoder will
bring you back with the new backlight option to the frequency dial.
LOCK:
This function allows an easy and fast lock or unlock procedure for the dial
when you are working on a fixed frequency. Push the encoder for more than
1 second, turn the encoder until LOCK appears on the screen and make a
quick push. LCD will turn off and the encoder will remain inactive. To recover push the encoder for more
than 1 second.
EXIT:
This menu entry allows you to go back to the frequency dial without
changes. You only need to make a quick push on the encoder.
MENU FLOWCHART
L
C
D
B
A
C
K
L
I
G
H
T
L
O
C
K
.
.
.
.
.
.
.
.
E
X
I
T
.
.
.
.
.
.
.
.

ILER-DDS V2.1 VFO/DDS. Page 18
CONFIGURATION
In principle the ILER-DDS may seem very complicated, but it is not.
Prior to making any changes in the configuration you will have to study your project needs. Once you
know exactly what do you want and how to do it: configuration will be easy, simple and fun!
To activate the configuration menu you will have to power on the ILER-DDS while you keep
pushed the encoder. (pushbutton + power-on).
On screen you will see the first entry of the configuration menu, and turning the encoder will cycle
through all the options. One of them is “EXIT”, which will allow you to go back and start up the ILER-DDS
normally without making any changes.
LOWER LIMIT:
One of the entries is “LOWER LIMIT”. This is used to set the band lower
limit. Make a quick push, then you will have the option of entering any
frequency in the range 0 to 40 MHz in 50 kHz steps.
This is usually the lower limit of the amateur band the receiver or transceiver
is prepared for, but it may be placed at whatever frequency you like, even
out of band. Once the frequency is set, make a quick push and the ILER-
DDS will start-up normally.
Note: If you plan to use the ILER-DDS as RF generator you may adjust the limits to the ones you like for
your generator, even 0 and 40 MHz!
UPPER LIMIT:
Keep turning the encoder until you see “UPPER LIMIT” when you want to
set the band upper limit. Make a quick push, then you will have the option of
entering any frequency in the range 0 to 40 MHz in 50 kHz steps.
This is usually the upper limit of the amateur band the receiver or
transceiver is prepared for, but it may be placed at whatever frequency you
like, even out of band. Once the frequency is set, make a quick push and
the ILER-DDS will start-up normally.
YOUR CALL ?:
Keep turning the encoder until you see “YOUR CALL ?” and make a quick
push. You will program a welcome message at turn-on, typically your
amateur radio callsign.
With a quick push you will cycle between “CALL ON” and “CALL OFF”.
“CALL OFF” may be selected with a quick push when you do not want any
welcome message.
Should you want to program a message, go to “CALL ON” and make a quick push. Now you will se the
last programmed word (i.e. EA3GCY). You may enter up to 8 characters on the top line. The underline
shows the position to be programmed. Turn the encoder to cycle between letters, numbers and symbols
for each position. Once you are happy with the character selected make a quick push: the character will
get stored and the cursor will move to the next position. Complete all 8 positions. One of the available
characters is an empty space which may be also used. You will have to go through all 8 positions, even if
they are blank spaces to complete the process. After the 8th position is programmed, a quick push will
complete the process and the ILER-DDS will start-up normally.
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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
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ILER-DDS V2.1 VFO/DDS. Page 20
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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