Moderator: JR Moderator
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- Posts: 49
- Joined: Saturday, 15 November 2014, 17:55 PM
- Antenna: Full Wave Loop
It's a bit since I posted but I finally got around to finishing (is it ever "finished") the audio section of the cobra 2000 with the D104 mod . I took her out this afternoon for a spin and got some good audio reports.
The 2000 mod the converts the radio from high level modulation to low level modulation and can use either the stock preamp or line-in. I'm using Line-In on the audio clip. I tried modding the stock amp and used the D104 with it and it sounded better than I expected it to. There are two control knobs added to the face of the 2000 one controls the carrier inject level and the other is ALC adjust. The ALC adjust is only configured to be active when using the stock preamp.
The real p.i.t.a. is the extra switching that is required which really has nothing to do with audio. I'm in the process of finalizing that mess. I don't want to have to flip any extra switches or fiddle with knobs when going from AM to SSB. Although I can say I'm not really an SSB type and I have a few other things to do before before that.
The D104 has a FET preamp running in Class A
The audio is processed with Jamin' software. It's free for linux.
Link to more info on Jamin'
http://jamin.sourceforge.net/en/about.html" onclick="window.open(this.href);return false;
The receiver in the audio clip is my Cobra 148GTL with the precision diode detector and runs line out directly to the recording computer bypassing any audio bandwidth robbing sections in the radio. I think it's possible to hear the wide dynamic range of the unit.
This was a really fun project!!! I think I'm going to convert the 148 as well.
Small video of the2000 modulating on a 'scope with the D/C set at 2 Divisions. I'm not sure what happened to the audio but I was saying "Fooooour". This was taken during the "will this even work stage".
Link to Video
https://drive.google.com/file/d/0B1e2hi ... sp=sharing" onclick="window.open(this.href);return false;
Link to Audio Clip - Cobra 2000 / D104 - RX on Cobra 148GTL
https://drive.google.com/open?id=0B1e2h ... XFfUzRXQjg" onclick="window.open(this.href);return false;
73's and Happy Modding!!!!!!