CORSAIR CIRCUITS by Dave Martin
The Corsair 2007. 
click on picture to view in own window.
The Corsair 2007 is merely a refined version of the original Corsair.
Lessons learned & feedback from others who have built the circuits have led to the circuit you now see above.
A LM386 audio IC is used to series modulate Q2. The LM386's output on pin 5, sits at half the supply voltage. But is swung plus and minus with the audio being fed to it's input.In the
high current version Q4 allows Q2 to draw more current without damaging the LM386.
The PA, Q3, is a IRF530 which is configured as a linear amplifier. To set up you should, by adjusting RV2, set the DC voltage at TP1 to 2.5 VDC. Then by moving the turns on L6 further apart or closer together, get the RF power to read 10 Watts.
It must be noted that Q2,Q3 & Q4 must have heatsinks and that
Q3 & Q4 should be mounted using a TO220 insulation kit.



The table below shows the component changes needed to the PA and Filter section to use the CORSAIR on other bands.

BAND

L6

Turns

L7

Turns

Core

type

C17

pF

C18
pF

C19
pF

C20
pF

1.5MHz

17

30

T-50-2

1290

4610

1800

1800

1.9MHz

14

30

T-50-2

1290

4610

1800

1800

3.7MHz

10

21

T-50-2

560

2680

720

720

3.9MHz

10

21

T-50-2

560

2000

720

720

6.2MHz

7

14

T-50-2

560

2000

470

470

7.0MHz

7

14

T-50-2

560

1360

470

470

9.3MHz

5

12

T-50-2

700

1150

300

300

The second circuit shows the optional VFO. Values given will work over 6 to 8 MHz. The Corsair should be built with the crystal first.
VFO Values for other bands are shown below.
All the above coils are wound using 22 - 24 SWG, enamel covered copper wire.
TO5 Heatsink for Q2.
TO220 insulation kit for Q3.
Clip on heatsink for Q2.
TO220 Insulation kit for Q3.
Click on to view in own window

BAND

L

Toko Number

VC1
pF

C1
pF

C2
pF

C3
pF

C4
pF

1.8MHz

KANK3333

75

120

560

1000

1000

3.5MHz

KANK3334

75

100

560

1000

1000

7.0MHz

KXNSK4173AO

25

47

270

560

560

10.1MHz

KANK3335

25

68

220

680

680

14.0MHz

KANK3335

25

68

68

220

220

Last updated, 16/09/2007.
Remove Xtal from socket
when using VFO.
If the LM386 gets hot try this version of the circuit, here.
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