Most "mod" friendly radio....
- Conn
- Donor
- Posts: 121
- Joined: December 30th, 2006, 11:53 am
- Contact:
Most "mod" friendly radio....
So, what's everyone's opinion on the most easily modified CB radio?
From reading, looks like the Galaxy I own isn't TOO awful hard to mod.
I'm going shopping at GI Joes this afternoon and might pick up a new toy or two as a base. :D
I've had my eyes on the Cobra 148, but don't know anything about them.
Any help is appreciated!
Thanks!
Conn
From reading, looks like the Galaxy I own isn't TOO awful hard to mod.
I'm going shopping at GI Joes this afternoon and might pick up a new toy or two as a base. :D
I've had my eyes on the Cobra 148, but don't know anything about them.
Any help is appreciated!
Thanks!
Conn
- SAVAGESAM
- Duckplucker
- Posts: 131
- Joined: December 19th, 2006, 10:14 am
- Contact:
I have a 29
Please give me a list of mods you would do and why/what they will do. Thanks. Btw My radio is stock.BigBopper wrote:Most mod easy radio is the Cobra 29's and 25's
Cobra 29 LTD:
Receive Boost: Locate pin 14 of the PLL chip, and the Positive (+) side of C-12. Install a 22k-220k ohm resistor between these two points. The smaller the value, the more the receive is boosted. Use CARE when soldering to the PLL chip! If desired, this mod may be wired through a switch.
Supertune: Replace the stock final with a 2SC1969 unit. Solder a jumper across D8 (this may cause receive distortion at high volumes, remove jumper if it does). Solder a 68pf cap across C62. Solder a 68pf cap across C59 if there is already a 33pf across it. If there isn't, use 100pf instead. Replace R 55 with a 10-15k resistor, and solder a 33-55 pf cap across that resistor. Replace R58 with a 4.7 ohm resistor. Set VR4 just a bit to the right of half-way open. If D11 or C3 have been removed, replace them. D11 is a simple small-signal swithcing diode like a 1n147, and C3 is just a 1uf electrolytic. If TR18 has been removed or cut, replace with a 2SA733. Spread Open L12 a tiny bit, and adjust L16 for best swing, using a loud, steady "aaaaaaah" sound into the mic (or if you have a function generator, set it up for 1khz at about 16mv output, and use that. MAKE SURE to use heat-sink compound (a very light coating is sufficient) when mounting the new final, and MAKE SURE the final mount screw is tight!
Cobra 25 LTD:
Supertune: Replace the stock final with a 2SC1969 unit. Solder a jumper across D10 (this may cause receive distortion at high volumes, remove jumper if it does). Change R43 to 4.7 ohms. Remove C149. Place 82-150pf cap across C 46. Place 33-68pf cap across C42 (select for best output). Set VR5 half-way open. If D9 or C6 have been removed, replace them with the same values specified in the 29 procedure above. If TR14 is cut or missing, replace it with a 2SA733 unit. Spread open L8 a bit, and adjust L10 for best swing, using a loud, steady "aaaaaaah" sound into the mic. MAKE SURE to use heat-sink compound when mounting the new final, and MAKE SURE the final mount screw is tight!
The best is a basic Peak and tune for max output,
Receive Boost: Locate pin 14 of the PLL chip, and the Positive (+) side of C-12. Install a 22k-220k ohm resistor between these two points. The smaller the value, the more the receive is boosted. Use CARE when soldering to the PLL chip! If desired, this mod may be wired through a switch.
Supertune: Replace the stock final with a 2SC1969 unit. Solder a jumper across D8 (this may cause receive distortion at high volumes, remove jumper if it does). Solder a 68pf cap across C62. Solder a 68pf cap across C59 if there is already a 33pf across it. If there isn't, use 100pf instead. Replace R 55 with a 10-15k resistor, and solder a 33-55 pf cap across that resistor. Replace R58 with a 4.7 ohm resistor. Set VR4 just a bit to the right of half-way open. If D11 or C3 have been removed, replace them. D11 is a simple small-signal swithcing diode like a 1n147, and C3 is just a 1uf electrolytic. If TR18 has been removed or cut, replace with a 2SA733. Spread Open L12 a tiny bit, and adjust L16 for best swing, using a loud, steady "aaaaaaah" sound into the mic (or if you have a function generator, set it up for 1khz at about 16mv output, and use that. MAKE SURE to use heat-sink compound (a very light coating is sufficient) when mounting the new final, and MAKE SURE the final mount screw is tight!
Cobra 25 LTD:
Supertune: Replace the stock final with a 2SC1969 unit. Solder a jumper across D10 (this may cause receive distortion at high volumes, remove jumper if it does). Change R43 to 4.7 ohms. Remove C149. Place 82-150pf cap across C 46. Place 33-68pf cap across C42 (select for best output). Set VR5 half-way open. If D9 or C6 have been removed, replace them with the same values specified in the 29 procedure above. If TR14 is cut or missing, replace it with a 2SA733 unit. Spread open L8 a bit, and adjust L10 for best swing, using a loud, steady "aaaaaaah" sound into the mic. MAKE SURE to use heat-sink compound when mounting the new final, and MAKE SURE the final mount screw is tight!
The best is a basic Peak and tune for max output,
- GOTA Go
- Wordwide & Qualified
- Posts: 508
- Joined: August 9th, 2006, 9:26 am
- Contact:
- 316
- Wordwide & Qualified
- Posts: 1,462
- Joined: January 1st, 2007, 8:43 pm
- Handle: 316
- Real Name: Skylar
- Antenna: Wilson 5K
- Radio: RCI 2950 and IC-7000
- Contact:
- SAVAGESAM
- Duckplucker
- Posts: 131
- Joined: December 19th, 2006, 10:14 am
- Contact:
Two questions Re:29
What would it Cost me to have you do that? What would the difference be before and after?