Cobra 2000 GTL help with SSB lower ouput

[Adamf]

Yes.

Thanks.

 

[Robb]

Quick question, I am going to adjust in SSB mode, correct? I guess that is why I need to produce the tone, yes? Thanks

http://www.freesound.org/people/klangfabrik/sounds/28636/

 

[222DBFL]

If you have an IPhone there is an app called Tone Generator. Works great for performing this kind of work. Im sure Android has their own app as well. It's pretty loud out of my iPhone 6 as far as tone volume goes and I have many settings as well.

 

[RBR762]

TX Mixer Amplifier stage mod:

Locate IC5, which is labeled S042P. This is the TX mixer amplifier IC.
Change R190 from 100 ohm to a 47 ohm. R190 is located next to IC5 on the right.
Flip the radio over, locate IC5 again.
Solder a 330 ohm resistor from pin 5 to PCB ground as shown below.

Also, check the value of R183, it is located just to the right of TR39, which is the TX pre-driver transistor (labeled C1973). If R183 is 12 ohms, change it to 10 ohms. The older 148's and 2000's had a 12 ohm resistor at R183, the newer radios had a 10 ohm resistor.

This should bump up SSB output 4-7W, depending on the radio. You may see about a 1/2W or so deadkey change on AM, but your modulated output will be higher.


~Cheers~

ExitThitreen......the pic is now disabled showing the pin5 to ground location......I can figure out the locations just want to make sure there are no traces that need to be cut first.

 

[BAGEBOY]

TX Mixer Amplifier stage mod:

Locate IC5, which is labeled S042P. This is the TX mixer amplifier IC.
Change R190 from 100 ohm to a 47 ohm. R190 is located next to IC5 on the right.
Flip the radio over, locate IC5 again.
Solder a 330 ohm resistor from pin 5 to PCB ground as shown below.

Also, check the value of R183, it is located just to the right of TR39, which is the TX pre-driver transistor (labeled C1973). If R183 is 12 ohms, change it to 10 ohms. The older 148's and 2000's had a 12 ohm resistor at R183, the newer radios had a 10 ohm resistor.

This should bump up SSB output 4-7W, depending on the radio. You may see about a 1/2W or so deadkey change on AM, but your modulated output will be higher.


~Cheers~

Do you still have this photo as it is currently unavailable