J
JustinDePolis2
Guest
<blockquote>Quote:<hr>Someone was talking about exports at a key down and how they are never seen/used in that comp. environment. Why do you think this is? Also How come the Cobra 25 sounds so good on am? What are these exports lacking that this little radio has<hr></blockquote>
The thing that the exports lack, is the type of modulation circuit that the Cobra 25 / 29 uses. The transformer and the circuitry works differently. This causes strong positive peaks, useful in key-downs. The negative peaks (in the Cb world when they are over modulated) are times when the RF power reaches zero for an infinite amount of time. This can be bad. As far as harmonics, well, this is the least of the problems and where a lot of people would like to point the finger, my advice is to use a spectrum analyzer.
<blockquote>Quote:<hr>Also In your 50 watt mod, is it adjustable so I can run wide open at 50 watts and then turn it down to like 4 watts swinging 15-20 for an amp that has a built in driver? is that possible?<hr></blockquote>
Our 50 watt modification means 45-50 watts peak to peak, which is how AM is read, wattage-wise. The peak with our variable always stays the same, while you can vary the carrier from 1 1/2 watts to 8 watts.
<blockquote>Quote:<hr> got one off of ebay for $30 with shipping and when I got it it produced 1 watt carrier and modulated to 4 watts peak. I noticed a horrendous feedback problem and that was solved by removing the resistor combo that was used for feedback. then i started turning the slug next to the final and spreading coils and it produced a 5 watt carrier swinging to 23 watts peak. then I removed one leg of d19 and placed a 2000 ohm resistor on it. people said I sounded better but I definitely didn't hear any raspiness when I heard it on another radio. <hr></blockquote>
i cannot comment on what the other place did to this radio, they sound like they might have been confused?
<blockquote>Quote:<hr>. I think it sounds very smooth and powerful. not crunchy at all. then I flipped the radio over and a isaw a small ceramic capacitor ripped off the board on one leg near one corner. i just figured it would connect to a jagged solder spot i saw and I resoldered it and it works no different. <hr></blockquote>
Not to sound rude, but there's no other way to put it... a small ceramic cap in the corner doesn't tell me much at all.
<blockquote>Quote:<hr>. it also has to resistors wired in series next to the capacitor on the board, dont know what they are for, def. not factory, any idea? <hr></blockquote>
See above.
<blockquote>Quote:<hr>Is it worth doing a 1969 swap? what could I gain if i fully tricked this radio out, also can you get new front chrome trim rings and face plates?<hr></blockquote>
The 1969 swap is a good idea, but I have yet to see ANY shop do it correctly. When you do this the driver needs changes, and the circuit needs changed around the 1969. We can get face plates, but I need to know what version of the 25 that it is. (classic, NW, NWST?)
I hope that this answers all of the questions that you had, if there are any more, please feel free to ask, just give me a day or so to reply. Just because I'm logged in doesn't mean that I'm typing. I like to read what other people contribute on here too.
Take care,
Justin
Click Here To Go To FG Best Communications
A word to the wise is not necessary; it’s the stupid ones that need the advice. - Anonymous</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=happyhamer>Happy Hamer</A> at: 2/8/05 4:24 pm
The thing that the exports lack, is the type of modulation circuit that the Cobra 25 / 29 uses. The transformer and the circuitry works differently. This causes strong positive peaks, useful in key-downs. The negative peaks (in the Cb world when they are over modulated) are times when the RF power reaches zero for an infinite amount of time. This can be bad. As far as harmonics, well, this is the least of the problems and where a lot of people would like to point the finger, my advice is to use a spectrum analyzer.
<blockquote>Quote:<hr>Also In your 50 watt mod, is it adjustable so I can run wide open at 50 watts and then turn it down to like 4 watts swinging 15-20 for an amp that has a built in driver? is that possible?<hr></blockquote>
Our 50 watt modification means 45-50 watts peak to peak, which is how AM is read, wattage-wise. The peak with our variable always stays the same, while you can vary the carrier from 1 1/2 watts to 8 watts.
<blockquote>Quote:<hr> got one off of ebay for $30 with shipping and when I got it it produced 1 watt carrier and modulated to 4 watts peak. I noticed a horrendous feedback problem and that was solved by removing the resistor combo that was used for feedback. then i started turning the slug next to the final and spreading coils and it produced a 5 watt carrier swinging to 23 watts peak. then I removed one leg of d19 and placed a 2000 ohm resistor on it. people said I sounded better but I definitely didn't hear any raspiness when I heard it on another radio. <hr></blockquote>
i cannot comment on what the other place did to this radio, they sound like they might have been confused?
<blockquote>Quote:<hr>. I think it sounds very smooth and powerful. not crunchy at all. then I flipped the radio over and a isaw a small ceramic capacitor ripped off the board on one leg near one corner. i just figured it would connect to a jagged solder spot i saw and I resoldered it and it works no different. <hr></blockquote>
Not to sound rude, but there's no other way to put it... a small ceramic cap in the corner doesn't tell me much at all.
<blockquote>Quote:<hr>. it also has to resistors wired in series next to the capacitor on the board, dont know what they are for, def. not factory, any idea? <hr></blockquote>
See above.
<blockquote>Quote:<hr>Is it worth doing a 1969 swap? what could I gain if i fully tricked this radio out, also can you get new front chrome trim rings and face plates?<hr></blockquote>
The 1969 swap is a good idea, but I have yet to see ANY shop do it correctly. When you do this the driver needs changes, and the circuit needs changed around the 1969. We can get face plates, but I need to know what version of the 25 that it is. (classic, NW, NWST?)
I hope that this answers all of the questions that you had, if there are any more, please feel free to ask, just give me a day or so to reply. Just because I'm logged in doesn't mean that I'm typing. I like to read what other people contribute on here too.
Take care,
Justin
Click Here To Go To FG Best Communications
A word to the wise is not necessary; it’s the stupid ones that need the advice. - Anonymous</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=happyhamer>Happy Hamer</A> at: 2/8/05 4:24 pm
