This gadget is principally meant to
be an inexpensive ($9.99) way to add
a digital operating frequency display to homebrew radios such as the
BITX-20, ARRL Homebrew challenge radios from KD1JV and N3ZI, 40-40 from
the New England QRP club, SW+ from small wonder lads, the popcorn
superhet, MMR40 and BITX20A from Hendricks QRPkits, and many others. It
can also be useful with vintage analog/tube multi band radios. A
programmable IF offset allows the counter to measure the VFO
frequency
but display the actual operating frequency. It can also be used as a
general purpose frequency counter.
I will be offering a Semi kit and a full
kit. But I
strongly recommend that you consider the Semi Kit, The wiring is
so simple you can build it on a piece of vector board or dead bug style
in less than 1 hour. Other components (resistors and capacitors) needed
are non critical and available from multiple
sources. Take a look at the schematic and you can see how simple
the wiring is.
- Programmable IF frequency, and VFO mode (VFO+IF, VFO-IF, IF-VFO)
- S/W Programmable to accommodate external /n prescaler (n
can be 2,4,5,8,10,16)
- Operates from Vcc 3 to 5 VDC, A 3 terminal regular is recommended for 12v operation. 1-3 ma current draw.
- All programmable options stored in non volatile EEPROM, so they only have to be set once.
- 2 pushbuttons required for programming. So you can connect these up temporarily to set your IF and Formula. Once complete you can disconnect these and the until will work fine.
- Requires approx. 300mV rms to count, you can add a simple amplifier for higher sensitivity.
- uCode, includes anti jitter s/w which prevents LSD from jittering between two values.
- Measures VFO frequencies up to 5.5Mhz without prescaler, up to 55 MHZ, with /10 prescaler.
- Displays operating Frequency up to 199MHz.
- 32 bit internal math, 12.5Hz internal accuracy, 100hz displayed
- No XTAL trim cap required, correction applied in S/W.
- Update rate approx. 20ms w/o prescaler. 80ms with /4 prescaler..
- No blink, low power, display does not update unless freq. actually changes.
- Extra digits on LCD, and spare Analog/Digital inputs allow for
possible enhancement.
- NO soldering of Surface mount components required.
- SEMI Kit only $9.99 consisting of::
- Assembled LCD Display Module
- Programmed Microcontroller.(ATtiny24)
- XTAL 13.44MHz
- You supply just 9 non-critical R's and C's
Semi Kit, $9.99, 3 Key components(LCD,uP,XTAL)
Buy now, will ship by 5/31/2008
Full Kit w/PCB $24.99 Avail 7/15/2008
Assembled and Tested $49.99 Avail 7/15/2008