N3ZI LCD
Digital Dial
Vintage Radio Version
Shown with optional LCD cable
I have had many requests for a version of my digital dial that will
work well with Vintage radios. These radios present a bit of a
challenge because the frequency plan changes from band to band, and
sometimes is inverted.
SWAN 350/400/500: These radios have an IF of 5173KHz or 5500KHz,
and the VFO
is above the operating frequency for the lower bands (80,40) and below
the operating frequency for the higher bands. For example for 80
Meters, the VFO runs from 8670 to 9180 to cover 3500 to 4000, for 20
meters the VFO runs in the same range, but the radio operates from
13850 to 14350, approx. This also gives you a automatic USB/LSB
swap. For all these cases you need a two mode
a + IF and a -IF mode. The design I have working now,
allows for the entry of 9 IF's (expandable) But for radios like
the SWAN, you really only need two. But other radios with more
complex IF schemes can be accommodated.
After you've set up the counter, you use the buttons to toggle through
the IF's It takes approx. 1 second to switch, and the actual IF
frequency is displayed while the button is held down. One button
increments, the other decrements, both wrap around so that only valid
entered IF's are used. In the case of SWAN radios with just 2 IF
entries, both buttons do the same thing, just switch to the other
IF. The buttons are SPST-NO switches, so you can add a pushbutton
switch somewhere in parallel with the switches on the PCB if you want a
switch that's easy to reach.
These digital display's / frequency counters are sold as a kit.
The
display is large with high contrast digits.
Radio Shack's 6x3x2 project box makes a nice enclosure .(Catalog #:
270-1805)
Features & Specifications:
- All components show on the schematic below included in kit,
including PCB.
- Measures VFO frequencies up to 30 MHz & displays operating
Frequency up to 99 MHz.
- You supply, solder & wire only.
- No surface mount components to solder.
- Simple, straight through connections to LCD module.
- Operates from AC (6v-13v) or DC(8v-18v) power source, 3-4 mA
Current draw.
- 9 separate Programmable IF frequencies, and VFO mode (VFO+IF,
VFO-IF, IF-VFO)
- 2 pushbuttons included for programming IF's and Formula, and
switching IF's
- All programmable options stored in non volatile EEPROM, so they
only have to be set once.
- Requires approx. 300mV rms. to count.
- uCode, includes anti jitter s/w which prevents the readout from
jittering
between two values.
- 32 bit internal math
$26.50, plus S/H ($2.99 US)
Includes all components in above schematic, plus PCB
You need to supply, Solder,
Wire, power source.
NOW Shipping, 1-3 days ARO.
Order from this page
Questions? Email me at
N3ZI (at) pongrance (dot) com
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