Condor Conversion to 80m and 40m

Main

Version:

Jan 9, 2024:
Revised: v1.4

Part 3: Converting the Condor 1W SSB HF Transceiver

to 80m/40m Amateur Radio Operation

The Condor is a two channel crystal controlled 1W HF QRP SSB transceiver designed for Search and Rescue in New Zealand in the early 1980s. This page, the third part of a series of pages about this radio, describes the process to convert the original Condor to 80m and 40m HF ham band operation using the "SC+C" VFO.

Figure 1 : A modified Condor HF SSB SAR handheld transceiver with the new SC+C VFO module at upper left

Background

The Condor transceiver is a compact handheld battery-powered 1W SSB transceiver. Originally designed for operation on two fixed 3MHz and 5MHz Search and Rescue (SAR) frequencies, this modification permits the transceiver to be operated by licensed amateur radio operators on the 80m and 40m bands.

Features of the Modified Condor Transceiver

This modification also extends the overall functionality of the radio. The current feature set can be summarised as follows:

•    3.50 – 3.75MHz (80m) and 7.00 – 7.30MHz (40m) tunable coverage (60m optional)
•    User programmable high and low band VFO tuning limits
•    User programmable start-up/power-up frequencies for each band
•    Selectable VFO tuning rates – 10 and 100Hz, 1 and 10kHz steps
•    SSB (A3J) with optional automatic USB (60m) and LSB (80m) mode selection
•    64 x 32 pixel OLED display
•    Full 6-digit frequency display with 10Hz resolution i.e. 3.684.53 MHz
•    OLED tuning step indicator of currently selected tuning rate
•    S-meter bar-graph display (Linear from -110dBm to -60dBm i.e. S0 to S9+20dB)
•    9-12V OLED expanded battery level meter (on OLED display)
•    Power switch
•    Band switch
•    PTT pushbutton
•    Tuning lock button (Lock mode status icon appears on the OLED)

•    Rx sensitivity: Better than 2.5uV 12dB SINAD (Measured 0.35uV for 10dB S/N)
•    45 dB adjacent channel rejection (55dB with optional ceramic filter)
•    Tx: 1W PEP output
•    40dB carrier attenuation (45dB measured)
•    40dB opposite sideband attenuation (55dB measured)

•    12V (8 x AA-cell) internal supply, 9 – 12V (MAX!), optional external 12VDC power
•    Rx: 60mA Tx: 180mA
•    160 x 57 x 55 mm
•    520 gm

Condor Transceiver Production Variants

There are two main variants of the Condor transceiver. The version shown here is the decommissioned New Zealand Police Condor radio. This was fitted with a rotary switch to select upper or lower sideband (USB or LSB) on either the 3MHz (night) or 5MHz (day) crystal controlled channels.The front panel also features a BNC female panel socket for the antenna in addition to the standard pair of banana sockets.

The other version is fitted with a toggle switch for channel selection. It was permanently wired in USB mode.

The circuit of the transceiver remained consistent across variants and throughout its production with only minor changes to the circuit. These will only be detailed here if they affect the modification process.

Condor Transceiver Maintenance Information

A complete copy of the Condor transceiver maintenance manual is available for download in the Downloads section below. The schematic of the UNMODIFED/ORIGINAL Condor is also separately available in that section. Sincere thanks must go to the New Zealand Police for this document and for permission to make it available for distribution.

The schematic of the MODIFIED Condor has been prepared as a separate document and is also available in the Downloads section. This may be periodically updated.

Modification Process Assumptions

The following procedure assumes:

The Condor to be modified is fully operational on the original 3MHz and 5MHz channels and meets the specifications described in the Condor maintenance manual.
A programmed and tested SC+C VFO module is available, and
The original front panel is to be modified and reused.

Note: If sufficient interest exists in converting Condor transceivers for ham use, bearing in mind the procedure described below and the experience, expertise and tools required to adequately undertake this work, then a replacement front panel assembly kit comprising a 3D-printed panel frame and a CNC-milled metal panel insert will be designed and made available. The cost (Q1/2024) is estimated to be about $NZ25 plus P&P.

Modification Process

This procedure is separated into seven stages for convenience. These stages include:

Disassembly of the Condor
BPF Modifications
Transceiver PCB modifications
Front panel assembly
Alignment and testing

THANKS!

The preparation of these instructions have been a massive team effort. Sincere thanks to Keith ZL4JA for his invaluable assistance with the extensive checking of the miriad of details documented here. The completion of this work would not have been possible without Keith's help including his construction of a SC+C VFO module and the modification of another Condor now successfully operating on 80m and 40m.

Stage 1 : Dissassembly

Remove and set aside the front panel panel pyellow plastic cap/cover - if the radio is fitted with one. Many have been lost over the years.

Remove the battery cover from the base and remove any batteries.

Remove and save the four front panel self-tapping screws

Figure 2 : Condor original front panel - Search & Rescue / NZ Police version

Ease the combined front panel and transceiver board assembly gently out from the enclosure

WARNING: Don't pull it out too far! As you slide it out, the microphone speaker connector wiring will reach its limit. Disconnect this green two pin connector (See Figure 3)

Ease the panel and transceiver board out further. A brass spring wire loop which grounds one of the antenna connectors will flick out. Ignore it for now. It's also likely the two battery wires (black/white) will reach their limit. It's best to disconnect them from the front panel DC connector.

The transceiver case can now be removed completely. Set it aside.

Figure 3 : Unmodified transceiver - Side view

Figure 4 : Unmodified transceiver - Underside of transceiver PCB and original front panel

Dismantle the channel switch, the antenna connectors and the PTT pushbutton from the front panel. Leave the connected wiring connected. If there is a rotary type channel switch on your Condor, in order to remove this, first use a very sharp pointed tool (e.g. scalpel) to flick off the cap at the very end of the control knob. This will reveal the compression nut holding the knob onto the switch shaft. Undo this and set the hardware and knob aside. The Channel switch will not be reused, but most of the other hardware will be refitted later.

Figure 5 : Unmodified transceiver - Side view of BPF and rear of original front panel

Ease the front panel away from the Condor PCB using a very small flat-bladed jeweller's screwdriver. It was originally epoxy glued in place. Clean any old glue off the PCB.

Cut the wires that connect to the transceiver PCB at the "switch ends" of the wires, NOT at the PCB. Don't attempt to desolder them! Set the switches aside.

Remove the existing crystal oscillator hybrid (U7) and set it aside.

Figure 6 : Condor component detail for disassembly steps

Desolder the output BPF capacitors (C1, C1A, C2, C2A) and set them aside (Item A in Figure 6) There may be two, three or four capacitor fitted on the original PCB.

Unsolder and remove the 100k resistor and 100n capacitor assembly (Item B in Figure 6) and set aside. Do not separate them. Unsolder and remove the toroid (Item C in Figure 6) and the associated red LED and set them aside.

Unsolder the grey coaxial cable highlighted with a dashed yellow line in Figure 7 and set this aside.

Figure 7 : Condor cable detail for disassembly step

Stage 2 : BPF Modifications

Output BPF:
Fit the following new capacitors (Output BPF):

C1    100pF disc ceramic
C1A    100pF disc ceramic. (Alternately, fit two capacitors at C1 and C1A that together give 200pF)
C2     82pF disc ceramic
C2A    No capacitor required (Alternately, fit two capacitors at C2 and C2A that together give 82pF)

Note: The location is shown in Figure 6 (Item A) and on the overlay diagram (Figure 10 below)

Dual BPF:
Remove L1 and L2 by desoldering them from the transceiver PCB. Use a good quality desoldering station fitted with a new tip (e.g. Hakko FM-204, Goot TP-100, etc). Do not attempt to desolder these inductors with other methods. DO NOT attempt to use a piston-type desoldering tool !!!!!

Now disassemble and modify L1 and L2. First, remove the metal shield can carefully. It is a tight press-fit on the coil base. You can use a sharp scalpel to help ease the can from the base.

Avoid the temptation to pull on the pins in the coil base. These are not strong enough for that. You can apply VERY gentle pressure on the cup core. Once separated, put the shield can to one side.

Unscrew the cup core from the coil base and set it aside.

Figure 8 : Internal construction of the shielded BPF inductor. The one illustrated here is larger than the ones used in the Condor transceiver to provide a clearer view of the internal parts

Have a careful look at Figure 9. This is a close-up view of the coil bobbin in one of the Condor shielded inductors (L1-L4). If you look closely, the wires can be seen running from the coil bobbin down via plastic channels in the coil base. They are each then wound around a pin on the coil base and soldered.

This coil wire has a solderable enamel coating. That means you don't have to scrape it in irder to solder it. Wonderful!
Image courtesy of Keith ZL4JA

Figure 9 : Internal detail of Condor inductor coil bobbin (Photo courtesy of Keith ZL4JA)

If you look again at Figure 9, you will see one bobbin coil wire lies OVER the other. This wire may come from either the top or the bottom of the coil bobbin. That was randomly determined by the assembly person at the factory. In any event, it is this wire we want for the next step in this modification.

Cut this wire and, using this free end, remove THREE turns from the coil on the coil bobbin. Do this very carefully. The wire is super-fragile, and the sides of the coil base are similarly delicate. If it's all covered in wax or soft glue, you may need to remove this first. A tiny wooden toothpick is a good tool for this.

Now run the wire so it neatly runs down again from the coil bobbin to the original pin. Make sure you also allow a little slack in the wire so that the cup core can be wound right down to the base of the coil.

Wind the wire around the original pin again and resolder the wire. Important: This coil wire uses a special enamel coating. You can solder right through it. It requires no tinning, and do not attempt to scrape the enamel off the wire. Just wind the end around the pin and solder it directly..

Replace the cup core and reassemble the coil assembly. Solder the inductor back into the transceiver PCB.

Now remove L3 and L4. Repeat the above process but this time, remove only ONE turn from each coil before reassembly and refitting into the transceiver PCB.

Careful!! Once the coil is reassembled, if you turn the cup core hard down to the bottom or up to the top of the adjustment range, the bobbin may break, or the threaded sides on the cup core or coil base may distort or break, or the coil wire going to the base pins may be cut.

Stage 3: Transceiver PCB Modifications

Add the following wires under the transceiver PCB:

From	To	Colour	Function
U7 pin 10	U5 pin 12	Pale green	AGC for new U7 (SC+C module)
U7 pin 7	Lock switch (Front panel)	Orange	VFO "Lock" pushbutton (See Note 1 below this table)
U7 pin 6	Rotary encoder (Front panel)	Yellow	Rotary encoder data wire (See Note 2 below this table)

Notes
1 : Wire is run under PCB to a gap by the front panel, then through this to the top-side and on to the Lock switch. See details in Figure 13.
2 : Wire is run under PCB to a free thru-hole by module U3, then through this hole to the top-side and on to the rotary encoder. See details in Figure 13.

Add the following wires on the Component side (top-side) of the transceiver PCB:

From	To	Colour	Function
S31m	S33	yellow	455kHz (U7 Pin 1)
S37m	S36	green	455kHz (U7 Pin 3)

Remove R30 (47R) from the transceiver PCB and replace it with a jumper. (See Figure 10)
Note: R30 and R31 may not be present on early versions of the Condor and the PCB layout may also vary slightly from that shown in Figure 10.

Stage 4: Front Panel Assembly

Fill, drill and cut the front panel for the new hardware. (Note: This section of the instructions may be replaced later by details appropriate for a new 3D-printed and metal plate front panel assembly if this option proceeds)

Mount a new miniature DPDT toggle switch and a new SPDT toggle switch on the panel. Connect the wires cut from the channel switch to SW1 and SW2 as shown in Figure 10.

Figure 10 : Condor component overlay and switch wiring detail

Using the paralleled 100k/100n removed earlier, refit this under the transceiver board. It is wired between AAA and the antenna socket ground (See Figure 11). This must be fitted carefully so that these parts do not bind with the enclosure as it is closing.

Figure 11 : Condor front panel detail

Rewire the external DC connector as shown in Figure 12. This replaces the non-standard DC connector wiring with a centre-positive arrangement.

Figure 12 : Revised DC Wiring - Original (left) and after modification (right)

Note: The positive wire going to the internal battery is shown here in blue for clarity. In fact, it's white.

Mount the rotary encoder, lock switch, OLED display and the encoder resistors as shown in Figure 13.

Figure 13 : Front panel display, lock switch and encoder wiring detail

Stage 5 : Alignment and Testing

Plug in the SC+C module into U7. The PCB notch should be closest to the front panel.

Temporarily plug the speaker/microphone connector into the transceiver PCB.

Connect the transceiver to a 12VDC power supply. Set the current limit to 250mA.

Turn on the transceiver and check the OLED shows the splash screen.

Connect a signal generator to each selected frequency in turn and align L1 - L4. (Take care!! These coils are delicate and difficult/expensive to replace) Once aligned, the receiver sensitivity should match that stated in the Condor maintenance manual.

Disconnect the signal generator and connect a 75 ohm dummy load and RF power meter.

Use an audio test oscillator and speaker to inject a 1kHz tone into the Condor mic/speaker.

Press PTT and check that the transmitter is outputting power on 80m and 40m.

Adjust VR1 and RV2 to set the output power on each band to 1W PEP. Note: There is some interaction between these settings so some "back and forth" is required to correctly set both bands correctly.

Check the output power across each band. It should drop no more than 6dB at band edges. Adjust L1 - L4 if required.

This completes the Condor modification.

Figure 14 : The front panel of the modified Condor.
The tuning control is at top left. The OLED display
is showing the Condor power-on logo.

Figure 15 : The OLED shows the frequency while the arrow indicates the tuning step size. The lower display 'line' shows the signal level (S9+ here) and, in the lower right corner of the OLED, the battery meter bar. The Lock icon, displayed between the S-meter and battery meter when
enabled, is not shown here.

Note: If there is sufficient interest, a replacement front panel assembly will be designed and fabricated with an improved layout of the display, RF connector, and user controls.