The VFO 1000/Collins is a direct digital synthesizer programmed to enhance the operation of Collins S-Line receivers.  There are 30 tunable memories that are programmed to provide the functions of VFO, MEMORIES, and GENERAL COVERAGE reception. The first 6 memories are factory assigned for the 80 meter to 10 meter ham bands. The remaining bands are assigned to provide general coverage of the shortwave bands. They can be easily user re-assigned in any way you wish up to 30MHz.  Some memories could be your favorite net frequencies, others could be used for shortwave broadcast stations.  The encoder has 5KHz, 1KHz, 100Hz, and 10Hz tuning steps, and can be locked to prevent accidental changes.  An  LED indicates when the encoder is active.  There is a 50KHz step available in the setup mode to speed-up  frequency entry.

Included is a crystal controlled 2.7MHz oscillator to replace the receiver internal VFO.  This gives complete control of Frequency Accuracy, and Stability to the VFO 1000.


BAND is a dual push button switch used to step close to the desired frequency.

TUNING KNOB is used for fine tuning.

PUSH BUTTON      changes the tuning step.
Fine                        Switches between 10Hz and 100Hz
Normal                    For 5KHz steps, push and hold then push band up
                                For 1KHz steps, push and hold then push band down

ADAPTER SWITCH    Switches between the VFO and ham band crystals.

2.7MHZ OSCILLATOR SWITCH    Switches the oscillator ON and OFF
                                                        ON - Toward the Back
                                                        OFF - Toward the Front


POWER: Red RCA jack and the red switch.  12 to 20 VDC.

OUTPUT: White RCA jack. 


TUNING LOCK is the toggle switch.  It is used to disable the tuning knob, to prevent accidental changes.  A front panel LED indicates that the tuning knob is active. 


Included is an adapter with a tube socket and a toggle switch.  Remove the crystal oscillator tube, from the receiver.  Plug the tube into the adapter, then plug the adapter into the receiver.  The switch selects either the receiver crystals or the VFO.  Connect the coax cable from the RCA jack on the adapter to the WHITE VFO jack.  Plug the power cord into the red RCA jack.  The screw on the back is for ground.

To install the oscillator, remove the PTO/VFO tube and slip the eyelet over pin,  1, large end first,   then plug it back in.  Viewing the bottom of the tube, pin 1 is the first pin counting clockwise starting at the space.  It helps to temporally tape the wire to the side of the tube to hold it in place when plugging it back in.  Ground the black wire.  Connect the small RCA cable from the oscillator to the BLACK RCA jack on the VFO. The switch is used to select either the receiver VFO or the oscillator.


Switch the 2.7MHz ON (toward the back). When using the 2.7 MHz oscillator, set the tuning dial on the receiver to zero "0".  Use the BAND switch for course frequency  adjustment.  Final tuning is done using the tuning knob on the VFO 1000 and the operating frequency is displayed on the LCD display.  Select 1KHz tuning steps by holding the STEP button then push the BAND DOWN switch.  Select 5KHz tuning steps by holding the STEP button then push the BAND UP switch.

If you prefer traditional Collins tuning, set the VFO display to read the low end of the desired 200KHz segment, and switch the external oscillator off (toward the front).  Then tune using the receiver tuning knob.  The operating frequency in this case is the VFO display plus the receiver dial.  The tuning knob on the VFO can be disabled to prevent accidental changes.

For high accuracy, all bands that you use must be calibrated

To enter the setup mode, turn on power using the rear panel power switch while pushing STEP button.  Then SETUP is displayed, release the STEP button.

First accurately tune a station to calibrate against.  You can calibrate against an AM shortwave station using the SSB mode and it will be very accurate.  If the display is not reading correct, Power Down the VFO.  The VFO frequency will be stored.

To enter the setup mode, turn on power using the rear panel power switch then quickly push and hold the STEP button.  Then SETUP is displayed, release the STEP button.

When "Cal. Bands" is displayed, push the STEP button.  Using the TUNING KNOB, tune the display to read the frequency of the known signal.  The VFO frequency does not change, only the display changes.  Next push the Up or Down switch to store the correction, then Power Down the VFO.    That band is now calibrated.  Repeat this for any other bands you wish to calibrate.


The following setup instructions are for reference, just in case some unknown event causes your unit to require a full setup.

Set The Number Of Bands
When the "Set # Bands" message appears, Push the STEP button.  Use the Band up/down switches to set the number if bands to anything from 1 to 30.  When finished, press STEP button to exit, then it will go to normal operation.  If you add bands, those extra bands may have bad data in them, so you should check the other setup data for those bands.

Set IF Offsets  (Indicated by an "F")
When the "Set IF Offsets" message appears, Push the STEP button. Push the step button again to enter the 50KHz step mode.  Select the desired band, and enter the IF OFFSET shown in the chart below.  The tuning step is 50KHz in this mode.  Step to the next band and enter the offset.  Next push the Up or Down switch to store the last entry, then Power Down the VFO.

On Collins radios enter -3.150 on all bands, then switch to 5KHz step and change the 0 to 5 on all bands.

Set Band Freq.  (Indicated by an "S")
The Band Frequencies are the starting point for each band.  The last frequency used on a band is stored and becomes the starting point the next time that band is selected.  When the "Set Band Freq" message appears, push the STEP button.  Push the step button to enter the 50KHz tuning step.  Select the desired band number and enter the desired BAND FREQUENCY.  Repeat this procedure for all bands.  Next push the Up or Down switch, then Power Down the VFO.

Reset/Clear :      D O  N O T  D O  T H I S
                            DOING THIS WILL DELETE ALL OFFSETS AND

When the "Reset/Clear" message appears, Push the STEP button.  You are asked to confirm with another STEP button press. All IF Offsets and Band Frequencies are set to 0.0.   Progress is displayed on the LCD.   If you do nothing when it asks "Confirm" then after a few seconds it will say "Nothing Done"  In either case it proceeds to normal operation.

In case you need to reenter the IF Offset and Band Frequency data.
The Band Frequencies can be anything you prefer up to 30MHz, or reenter the factory settings below.  The Band Frequencies are only a starting point to get close to your desired frequency

The IF Offset is (minus) -3.155MHz on all bands.

On Collins radios enter -3.150 on all bands, then switch to 5KHz step and change the 0 to 5 on all bands.


1    3.5            11    7.5            21    12.5
2    7.0            12    8.0            22    13.0
3    14.0          13    8.5            23    13.5
4    21.0          14    9.0            24    15.0
5    28.0          15    9.5            25    15.5
6    28.5          16    10.0          26    16.0
7    4.0            17    10.5          27    16.5
8    4.5            18    11.0          28    17.0
9    5.0            19    11.5          29    17.5
10  6.0            20    12.0          30    18.0