DFD3

DFD3 has 10Hz resolution and digital filtering to eliminate flicker due to roundoff error.

DFD3 measures only the VFO. It has it's own band-switch which must be set to match the radios band-switch.

Installation requires only access to the VFO which is available on a rear panel connector of many radios.

DFD3 is user programmable for most any multi-band radio. First the user programs the number of bands the radio has. Then for each band, programs an offset value. The offset can be any value up to 40MHz in 10Hz steps.

The data is stored in EEPROM for retention without power.

Each band can be accurately calibrated by tuning a known frequency in the band (ie: crystal calibrator) and adjusting the offset to cause DFD3 to display the exact frequency. This data is also stored in EEPROM so it's a once in a great while deal.

Here's the really neat thing. DFD3 will program itself for many popular radios. The user mearly tunes the bandswitch until the model of their radio is displayed and presses a button. DFD3 Operation and Programming instructions

If you have a bunch of single band QRP rigs, you can program DFD3 bands as one band per rig. You can then move DFD3 from rig to rig by simply setting the band-switch to match the rig it's connected to.

Any DFD is available assembled for an additional $20.00
TCXO Reference Oscillator option included

 

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Price $49.95 + $1.50 S/H Available NOW

Controls Kit add $7.00 includes 10K potentiometer with power switch, one SPDT spring loaded to center toggle switch, 3 SPST NO pushbutton switches, two 10K resistors and one 1K resistor. Everything needed to implement any of the MODE and BAND select options.

LED Backlit Display module also available.

This module is the same size as the non-backlit module and replaces it directly. You will have to supply a dropping resistor to set the current from your primary power source. The forward voltage drop of the LEDs is 4V and the maximum current is 200ma. The unit lites up pretty good with 30ma. At this setting it can be powered continuously from the on-board 5V regulator through a 33ohm 1/4 watt resistor. From 12V you need an 80ohm/2W resistor for 100ma, or a 160ohm/1W resistor for 50ma.

For LED backlit module instead of regular module add $7.50

BIGGY lcd display module option

dfd103.jpg (24641 bytes)

A fully assembled and tested unit is available from

Electronic Specialty Products

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And another of their fine products

Electronic Specialty Products, LLC • P.O. Box 711 • Geneva, FL 32732

mailto:cs@electronicspecialtyproducts.com

 

DFD3 Operation and Programming instructions

japan.gif (961 bytes) Japanese language

Courtesy of Philip/JA3KEV

DFD3 is for multi-band radios usually consisting of a crystal controlled converter followed by a tunable (variable) IF. Each band is programmed for an offset which, when added to the measured VFO frequency, produces and displays the RF frequency.

DFD3 allows for 32 bands. There is no law that says these bands have to be on the same radio. You can store three 5 band radios, a 10 band radio, a 3 band radio and 4 single band radios all at the same time (or any other combination). All you have to do is remember which bands go with which radio.

The offset frequency is determined by:

Suppose the band being tuned is 7-8MHz and the VFO tunes 3-4Mhz and that it tunes forward (RF increases as VFO increases) then

Had the VFO tuned backwards (RF increases as VFO decreases) then

A calibrate function allows you to tweek the offset for each band to get up to 10Hz accuracy. The offsets are stored in EEPROM so the calibrated values are saved until you reprogram or recalibrate a band.

DFD3 also stores CW, LSB and USB BFO offsets. These values are added to the RF frequency when the MODE selector in in the CW, LSB or USB positions. These values can also be calibrated. These offsets are zero for radios without crystal controlled BFOs but can be calibrated to match the BFO settings you use for each of these modes.

As a result, DFD3 will accurately display the carrier frequency of the receive or transmit signal in any mode.

Operating DFD3

DFD3 has only three operating controls, a BAND selector, a MODE selector and an ENTER button.

The BAND selector is a potentiometer, toggle switch (SPDT with spring return to center) or two pushbuttons as described in the assembly instructions. It's function is to change the band that DFD3 is operating on to match the band your radio is operating on. It increments or decrements the band number and during calibration it increments or decrements the frequency.

The MODE selector must be a potentiometer. It's function is to change the mode that DFD3 is operating in to match the mode your radio is operating in (AM, CW, LSB or USB). It's intent is to display the carrier frequency of the signal regardless of its type modulation. It's use is optional. You can chose to operate in the AM mode at all times where DFD3 displays the band number, however, it will not necessarily be displaying the carrier frequency.

During programming the MODE selector positions a cursor under the digit being programmed.

PROGRAMMING DFD3

To enter the programming mode turn DFD3 off. Press and hold the ENTER button while turning power on. Continue to hold the ENTER button.

When the MODE selector is to the left of center DFD3 is in manual programming mode. When it is to the right of center DFD3 is in auto-programming mode.

Manual programming mode.

DFD3 displays "#BANDS=XX"

When the BAND selector is to left of center the band number decreases. When it is to the right of center it increases.

Turn the BAND selector to adjust XX until it equals the number of bands your radio has (32 maximum). Release the ENTER button. The unit is now in calibrate mode.

Go to Calibrate mode (below) to complete the manual programming.

Automatic Programming mode.

DFD3 displays the manufacturer Followed by the radio model. Ie: Collins 75S-1

Turn the BAND selector to step through the available radio models. When your model of radio is displayed release the ENTER button. The unit will auto-program itself for your radio. DFD3 is now in the calibrate mode. Go to the calibrate mode to accurately calibrate each band.

Radio Models List

If your interest is in a single model of radio shown in BLUE then you should order DFD1A instead.
If you want a universal display for several models then order DFD3 anyway.
Frequency Counter   Zero offset, for use as test equipment
Allied                           A2515, A2517
Collins
32S-1,32S-2,32S-3,
51J-1,51J-2,51J-3,51J-4,51S-1,
75A-1,75A-2,75A-3,75A-4,
75S-1,75S-2,75S-3,75S-3A,75S-3B,75S-3C,(bands 13-28 are not programmed)*
If your only interest is an S line radio you should use custom DFD2 for the S line instead,
or C-75 for plug-n-play.
KWS-1,KWM-1,KWM-2, (bands 13,14 are not programmed.)*
R-388,R-390,R-390A,R-392
Davco DR-30
Drake
R1-A,(band 6 not programmed.)*
R2-A,R2-B,(bands 6-12 are not programmed.)*
R2-C,(band 6 not programmed.)*
R-4,R-4A,R-4B,(bands 6-15 are not programmed.)*
R-4C,SPR-4(bands 6-20 are not programmed.)*
TR-4
If your only interest is a DRAKE radio you should use DFD1-DRAKE instead,
or C-Drake for plug-n-play.
Galaxy GT-550
Hallicrafters
HT-44,S-20R,S-22R,S-38,S-40,S-41,S-47,S-51,S-52,S-53A,s-76,S-85,
S-107,S-108,S-118,S-119,S-120,S-125,S-129,S-200,S-210,S-240
SR-150,SR-160,SR-400,SR-400A,SR-500,SR-750,SR-2000,
SX-25,SX-28,SX-42,SX-43,SX-62,SX-96,SX-99,SX-100,SX-110,SX-111,SX-115,SX-117
Hammarlund
HQ-100,HQ-105,HQ-110,HQ-120,HQ-129,HQ-140,HQ-145,HQ-150,HQ-160,
HQ-170,HQ-180,HQ-200,HQ-215,(bands 20-24 not programmed)*
SP-400,SP-600
If your only interest is a HAMMARLUND radio you should use DFD1-HAMM instead,
or C-Hamm for plug-n-play.
Heathkit
HW-100,HW-101,SB-100,SB-101,SB-102,SB-300,SB-301,SB-303,
SB-310,SB-313,SB-400,SB-401,HR-1680
Henry TEMPO-1
Kenwood TS-520,TS-511,TS-900
If your only interest is a TS-520S/SE radio you should use custom DFD2 for the TS-520S instead,
or C-520 for plug-n-play.
MacKay 3010B,3010C
National
HRO-50,HRO-60,HRO-7,NC-2-40,NC-33,NC-46,NC-57,NC-60,NC-88,NC-98,NC-105,
NC-109,NC-125,NC-140,NC-155,NC-173,NC-183,NC-188,NC-190,NC-270,NC-300,
NC-303,NC-400,NCX-1000,NCX-500,SW-54
SBE SB-33
Squires
SS-1BS,(band 12 not programmed)*
SS-1R,SS-1T(band 11 not programmed)*
Swan 260,270,270B,300B,350,350C,400,500,500CX,700CX,700S,750CW
If your only interest is a SWAN radio you should use DFD1-SWAN instead,
or C-Swan for plug-n-play.
Yeasu
FT-101,FT-101B,FT-101E,Bands for the FT-101 are programmed in the same order as the YC-601 digital display.
FT-101Z,FRG-7,FTDX400,FRDX400,FLDX400,FTDX560
   
   

 

*Bands that are not programmed are auxiliary bands for which crystals were not supplied as standard. They can be manually programmed for whatever crystals you may have installed as follows: Turn DFD3 off, press and hold ENTER, turn unit back on to enter programming mode. Rotate MODE control left of center. DFD3 displays the number of bands this radio has. You can reduce this number to blank out any unused bands using the BAND selector. Release the ENTER button. Turn BAND selector to unused band. The offset will be zero. DFD3 displays zero if not connected to your VFO or your VFO frequency if connected. Go to the calibrate mode described below.

Obviously I don’t have all of these radios to test DFD3 with. Auto-program data was taken from data for each radio. In the event of a problem with a model or particular band call, e-mail, or write me about it and I will supply an updated chip and correct the error for future production.

Calibrate mode.

To calibrate the frequency set the MODE control to AM (displays band number to far right of display). To calibrate the CW, LSB or USB offsets turn the MODE control until the desired mode is displayed at the far right of display.

To enter the Calibrate mode press and hold the ENTER button after power has been applied and the MODE control has been set. Calibrating can be done either with the unit connected to your radios VFO or not. If it is connected then you are adjusting for the correct RF frequency to be displayed. If not you are adjusting for the correct OFFSET to be displayed. If your VFO tunes forward on this band (RF increases as VFO increases) there should be a ">" to the right of the "MHz" on the display. If it tunes backward (RF increases as VFO decreases) there should be a "<" to the right of "MHz".

The best procedure is to tune your radio to a known frequency near the center of each band. This can be supplied by the crystal calibrator built in your radio. Connect DFD3 to your VFO. Allow your radio to warm up to stabilize the VFO.

Turn the BAND selector (and your radio) to the band to program or calibrate. Tune to the known frequency. Press and hold the ENTER button. Rotate the MODE control to position the cursor under the digit to be incremented/decremented. A ">" indicates the offset is positive for forward tuning VFO and "<" indicates the offset is negative for reverse tuning VFO. Move the BAND selector in the direction of the arrow to increment the frequency and opposite the arrow to decrement it. You are actually adding or subtracting the number of Hz represented by that digit to the total frequency. For example, if the cursor is under the KHz digit you are adding or subtracting 1 KHz per step.

At the instant the displayed frequency is correct, release the ENTER button. If you miss it by a little simply repeat the process.

Repeat this procedure for each band. When all bands are programmed, turn DFD3 off and back on. This takes it out of the program mode

The purpose of the calibration mode is to correct for any errors in your high-frequency crystals. A good crystal might be 50 parts/million accuracy. At 30 MHz this could be up to 1500Hz error. The resolution of the frequency offset is 10 Hz so you should be able to get within 10Hz of the known frequency.

To calibrate the CW, LSB or USB offsets, turn the MODE control (and your radio) to the desired mode. Zero beat to the known frequency. Press and hold the ENTER button. The process is similar to calibration/programming except the cursor is forced under the 10Hz digit. At the instant it equals the known frequency release the ENTER button. Repeat this for each of the three modes. Do this on only one band, the mode offset applys to all bands. It is correcting for any errors in your SSB BFO crystals and setting the displayed frequency to the carrier frequency of the known signal. The resolution of the mode offset is 20 Hz so you should be able to get within 20 Hz of the known frequency.

This all sounds a bit complex and it may take a while. You will quickly get used to the operation of DFD3. Remember, it only needs to be done once. The manual programming or calibration will be lost if you reprogram the unit for a different radio. You can reprogram it or re-calibrate it a minimum of 10,000,000 times.

Remember, you cannot make a mistake that cannot be undone.

A jumper on the PCB allows you to select either 100Hz resolution (jumper ON) or 10 Hz resolution (jumper OFF).


 DFD3 Schematic
 DFD3 Assembly diagrams

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