The 30M WARCbler PSK-31
Rig Conversion Kit
By: Fred Spinner, W0FMS and Jeff Woods, W0ODS
(C) Copyright 2001, Fred Spinner and Jeff Woods -- All Rights Reserved
May 14, 2001
WARC-Bler Parts List:
|6||10.141 MHz Crystal||10.141 / Match Code|
|1||1000 pF Capacitor||102|
|3||100 pF Capacitor||101|
|4||120 pF Capacitor||121|
|2||33 pF Capacitor||33|
|2||27 pF Capacitor||27|
|3||330 pF Capacitor||331|
|1||6.8 uH Inductor||Silver/Blue/Gold/Grey/Silver|
|1||0.82 uH Inductor||Silver/Gold/Grey/Red/Silver|
|1||8.2 uH Inductor||Silver/Grey/Gold/Red/Silver|
|1||51 Ohm Resistor||Green/Brown/Black/Gold|
|1||180 Ohm Resistor||Brown/Grey/Brown/Gold|
|1||470 KOhm Resistor||Yellow/Violet/Yellow/Gold|
|1||1.2 KOhm Resistor||Brown/Red/Red/Gold|
|2||MPS5179 NPN Transistors||MPS5179|
|7"||Trifilar Magnet Wire|
Six crystals are provided. These have been matched for better filter performance. A two digit code is written on the crystal. The two or three crystals used in the transmit and receive filters, respectively, should have the same code. The crystal used for Y3, the BFO, need not be matched.
Four inductors are included with the kit. The WARC-Bler requires re-use of the original 6.8 uH inductor included originally as L1. It will be moved to L3. Replacements for the 6.8 uH inductor are available for $1 (shipped) from Twisted Pair Labs.
The new inductor color codes are somewhat faded, but given the known values, can be worked out. Contact Twisted Pair Labs for assistance if the values cannot be determined given the color band information in the parts list.
C6, R7, R8, R11, R12, R13, R15, R16, R17, R18
R6, R8, R15, R16, R17
L1, L2, L3, --IMPORTANT: Do not damage L1, 6.8 uH. This part will be re-used.
Place a 330 pF capacitor (331) in the C11 and C12 locations. The Low-Pass filter has been modified.
(Physically the filter section should look the same as before, but just with the modified components listed above.)
|Twist one lead of each of the three components together: 33 pF,
6.8 uH and 100pF. Solder the three leads together and trim off excess.
Don't take so much that the strength of the joint is compromised.
More can be removed after it's mounted.
Now, place the free lead of the 6.8 uH inductor in the C6 hole tied to the SA612. (This is the hole toward the "top" side of the board-- the top side being the side where the connectors are located.) The other hole of C6 is filled with the free lead of the 100 pF capacitor. (The "bottom" side of the board, toward the "NJ-QRP 9/00" writing.)
Ground the 33 pF capacitor by soldering to the grounded lead of D1, located near C6.
|A similar operation takes place in the former location of C8. Twist together and solder a 3.3 uH inductor and a 100 pF capacitor. Place the other inductor lead in the C8 hole tied to R6. The 100pF lead goes to the other hole of C8, connecting electrically to Y2. Place a 27 pF capacitor in the holes formerly used for R6. Remember, R6 shouldn't be there anymore. If it is, remove it.|
The 6.8 uH inductor for L1 is replaced by a 0.82 uH unit. Verify that C10 is 330 pF. Replace it with an (included) 330pF capacitor if necessary.)
Re-wind T1 with 6 turns of trifilar wire. This is included in the Warc-Bler conversion kit. Observe the same polarity used in the original Warbler. To tin the enameled wire, form a solder ball on your iron and set the tip of the wire in the ball. Wait for the wire to heat up. The enamel insulation will begin to bubble and darken. Slowly move the solder ball up the wire for the desired tinned length. Clean the tip of your iron, and run your fingernails over the tinned leads. Tin the leads a second time, and the tinning should be perfect. Use of a higher temperature iron is helpful, but not required. 800 degrees F works well, as does a soldering gun.
Scraping away the insulation with sandpaper or a blade is also acceptible-- if you do not nick the wire while scraping!
|The same construction used in the transmit filter will be used again in the receive filter. Twist together one lead of each of the following: 120 pf, 27 pF, 8.2 uH. The free leg of the 120 pF capacitor goes in the C18 hole tied to Y6. The inductor lead goes into the other hole, electrically tied to U2 pin 1. The remaining free lead (27 pF capacitor) is grounded by soldering to the grounded pin of C108 on the top side of the PCB.|
This completes the hardware modifications for your Warc-Bler.
Power-up the Warc-Bler, terminate the output in 50 ohms, and place it in transmit mode with no audio drive (remove the audio cable). Place the counter probe on U2 pin 7 and read the frequency. Tune C3 to set the frequency of the BFO to 10146.5 KHz. If using a receiver, a short antenna can be tacked to U2 pin 7 to aid signal pickup. This is a buffered output and has no effect on the frequency of Y3. Alternatively, attach the receive audio cable to the computer, and run Digipan. In DigiPan, set the 30m band configuration to use 10146.5 KHz LSB, and select the 30m band. Using a HF rig (attached to a dummy load nearby) to transmit a carrier on 10142.0 KHz using CW or AM, adjust the rig so the received carrier line lines up at exactly 10142.0 KHz.
Now, connect both audio cables, the RS-232 keying cable, and an antenna or dummy load. Place the rig in transmit and advance the PC's line out audio to the point where output power or supply current begins to decrease. Back off the input signal level so the drive is below the max level. A simple DC milliammeter in series with the Warc-Bler power supply is sufficient as a tuning indicator. Nominal input current at 13.8v is 300mA.
The Warc-Bler will produce about 2W at 13.5v and closer to 3W with a 15V supply. It is good operating practice to rely on the signal reports of others when adjusting your transmit levels. Don't splatter; be considerate of other ops. Oh, and have fun WARCbling!!!
THE END RESULT... Pure WARCbling Joy...
NEXT: Conclusion, Appendicies and Credits.