Retired


Image of prototype board/assembly

Description

The NorCal FCC-1 is a highly flexible frequency counter that incorporates features not found in any comparable unit. Its small size allows it to be incorporated into your favorite rig and your battery will hardly notice its modest current requirement. A high impedance input buffer provides high gain and isolates the counter to minimize loading of the signal source. The 4-bit band select input enables the counter to directly display your operating band and supports programmable parameters on a per-band basis. These parameters are stored in nonvolatile EEPROM. The 16 character by 2 line display is a high contrast, super twisted nematic LCD that's easily viewable over a wide angle in modest lighting conditions. Three menu-driven pushbuttons are provided to support user programming. Operation is as simple as connecting power and a signal source.

Adding a high frequency prescaler ahead of the FCC-1 extends the nominal 50 MHz inpit range into the GHz region. The FCC-1 will read the frequency directly because you can program the exact division ratio. You can also program the IF offset well into the VHF region for total flexibility. The display calculation allows for all combinations of VFO and IF frequencies.

The kit contains all of the necessary parts. There are no surface mount parts to contend with, so this is a kit suitable for builders with modest soldering experience. The board is solder-masked and has silkscreened component outlines for ease in assembly. The FCC-1 can be hardwired directly into your rig, or you can install your favorite connectors for flexibility.

With a future add-on board, the FCC-1 becomes a DDS frequency synthesizer that's capable of replacing conventional analog VFO's in many applications.

Designer's Comments

FCC-1 Firmware Update (November 11, 2005)

A few FCC-1 owners have reported strange characters appearing on the LCD display when power is first applied. Instead of "FCC-1" being displayed as the sign-on message, such messages as "$CC-1" or "4CC-1" show up instead. This behavior wasn't observed during development or beta test and only effects a small number of kits. Other than this, the FCC-1 performs normally.

The problem was isolated to LCD initialization timing. The LCDs use an internal RC clock oscillator which is used to control internal operations. The exact frequency varies from unit to unit and some are faster than others. For those displays with a slightly lower clock frequency, the firmware didn't pause long enough to allow the LCD to complete its internal operations before the first character was sent, and it was garbled. Increasing the delay fixed the problem, and that was the only change necessary.

Several of us NorCal folks sat down at a recent meeting and discussed potential applications of a 2-line LCD that was available. We tossed around several ideas and a frequency counter was a popular choice. Also high on the list of kits we would like to see was a DDS VFO. The final decision was left up to me.

The FCC-1 was an interesting project to develop. There were no specifications or performance requirements to meet and no size/weight/power restrictions. I was limited only by imagination. The kit didn't even have a name for a while. I started sketching out various designs as soon as I returned from that meeting and decided that a basic frequency counter kit with an add-on DDS VFO was a reasonable approach. The counter would be developed first.

The hardware and the physical specifications evolved together. My goal was to make the counter as small and light as possible and consume minimal power. I knew from previous experience that PICs and LCDs consume very little current; the bulk of the current consumption would come from the input amplifier. I decided that input sensitivity should be on the order of 30mV. A 4-bit band input was added and 3 pushbuttons would be used for programming. To support the add-on VFO, an expansion connector would be included. With this information, I developed the prototype hardware and showed off the basic counter operation at the next NorCal meeting, where it received an enthusiastic response.

Like the hardware, firmware development was fueled by imagination. Most counters I surveyed had various limitations, such as counting period, display resolution, etc. I decided that adding 1Hz resolution for precision measurements was an important feature to include. There's a lot of information that a 16x2 LCD can display, so I decided to extend the frequency display to 10 digits and indicate the operating band on the second line. Although the basic counter works to beyond 50 MHz, the software capabilities extend the display into the VHF and UHF regions. Of course, a prescaler is required, but the display parameters are programmed to account for that.

By the way, the FCC-2 DDS VFO is in development and should be available in several months. I'll post details in the future.

Bob, W3CD

Features

  • 16 character by 2 line high contrast LCD
  • 10 digit frequency display
  • Band annunciator
  • 3 pushbuttons for user programming
  • 16 nonvolatile band memories for programmable parameters
  • Programmable IF offset in 1Hz increments
  • Programmable display calculation: Direct, VFO+IF, VFO-IF, IF-VFO
  • Prescaler compensation
  • Display averaging to reduce least significant digit dither
  • Expandable to include a low power DDS VFO with shaft encoder

Specifications

Dimensions 1.9" x 3.05" x 1.125" (HWD)
Weight 1.5 oz.
Power Supply 7.5-20VDC @ 20mA, typical, reverse polarity protected
Input Sensitivity 30mVrms typical - see Manual
Input Impedance 1Meg || 15pF
Input Frequency Range 500 Hz to >50 MHz
Display Frequency Range 1Hz to >2.1 GHz
Display Resolution 1Hz, 10Hz IF Offset 0 to >268 MHz, programmable per band
Prescale Factor 1 to 255, programmable per band
Gate Period 100 mS, 1 Sec
Band Select 4-bit CMOS level input, with internal pull-ups
Band Annunciator 160m, 80m, 60m, 40m, 30m, 20m, 17m, 15m, 12m, 10m, 6m, 2m, 1.25m, 70cm, User, Direct
Controls LCD contrast, calibration, 3 pushbuttons
Inputs Power, Signal, Band Select, Keyline (future use)
Outputs Expansion Connector (future use)


Supporting Files

 FCC-1 Frequency Counter Controller Manual in PDF format


Page last updated: 10/29/2012, 08:19:34
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