CB tuning

[slprydk]

I have never heard a standard single final CB radio sound distorted by clipping the limiter..........never. Export radios are a different story though.
Clip the limiter and set the dead key to 3 watts, done. Don't spread the TVI trap coils, they serve a purpose.

Wait let me guess, you clip the diode and get 150% crystal clear modulation from your radio...

Have you ever looked at the RF envelope on an O-Scope or do you just listen on a crappy 3 inch speaker?

Dont judge your modulation by how your talkback sounds either, that is on the output of the audio circuit before it gets mixed with the carrier.

I bet your one of those people who think an echo mic sounds good too right...

 

[loosecannon]

telling cb'ers not to mess with the insides of their radios is like telling teenagers not to have sex.
LC

 

[psycho]

Wait let me guess, you clip the diode and get 150% crystal clear modulation from your radio...

Have you ever looked at the RF envelope on an O-Scope or do you just listen on a crappy 3 inch speaker?

Dont judge your modulation by how your talkback sounds either, that is on the output of the audio circuit before it gets mixed with the carrier.

I bet your one of those people who think an echo mic sounds good too right...

I am not one to micromanage the tuning of a CB radio to the point of using all kinds of expensive equipment. This is low cost CB...... not Amateur equipment. As dead as CB has become, who is going to care? Never said I used talkback and only an idiot would use that to tune a radio. I never heard of anyone getting 150% modulation by clipping a limiter......no need to exaggerate to make a point.
Most Cbers are not as anal retentive as you assume they are. Echo and reverb.....maybe if you have read some of my older posts about that subject, you wouldn't have made that foolish statement.
I should have known some asshole would get offended and go after me.....welcome to the forum anyway!!

 

[psycho]

telling cb'ers not to mess with the insides of their radios is like telling teenagers not to have sex.
LC

A couple of the locals around here have radios that key 1 watt on channel 1 and 4 watts on 40........think someone might have been turning anything that can possibly be turned?

 

[Robb]

I have never heard a standard single final CB radio sound distorted by clipping the limiter..........never. Export radios are a different story though.
Clip the limiter and set the dead key to 3 watts, done. Don't spread the TVI trap coils, they serve a purpose.

I would have to agree with psycho here. Clipping limiters and/or altering this circuit does have benefits for AM mode. It is better to alter the limiter than to eliminate it altogether, as a rule. It doesn't affect SSB anyway.

Pushing the filter coils back together after someone else had previously spread them also keeps the radio's output cleaner and a true wattage is realized w/o 'false' watts into a dumb meter. Every Cobra 29 I've ever worked on had the coils spread by someone previously, and I put that back to stock.

Echo -IMO- is fine so long as it is is turned waaay down. It is when the delay and depth are turned up too high that it makes it difficult to understand someone. I like it set so that it just pulls the modulation up w/o detecting any echo at all. Like any other radio adjustments, being judicious goes a long way.

 

[slprydk]

Let’s begin at the beginning shall we…

I offered up a way to increase modulation by changing the reaction time of the limiter circuit with the use of a capacitor. I did say that I did not like to cut the diode but did not bother to offer up an explanation as to why. I understand the way people run radios today and had decided to just offer the tip.

You quoted me and responded with:

“I have never heard a standard single final CB radio sound distorted by clipping the limiter..........never.”

You were the one who decided to make the topic about distortion using me as a target, I had only offered a tip.

“150% crystal clear modulation”

back in the late 70’s or early 80’s a guy who was trying to (I assume) impress me with his technical savvy used this line, it has just stuck with me as one of the most moronic things somebody could say about an AM signal and I have actually seen something similar to it posted in a chat or forum online, so I used it. Whenever somebody starts talking about clipping a limiter and running a radio all out it always comes to mind.

“I am not one to micromanage the tuning of a CB radio to the point of using all kinds of expensive equipment”

I guess your answer is no, you have never looked at the RF waveform on a scope, you only listen on a crappy 3 inch speaker.

“Never said I used talkback and only an idiot would use that to tune a radio.”

Never said you used it to tune a radio, I said you used it to decide how the output sounded, or didn’t you understand.

“As dead as CB has become, who is going to care?”

This statement to me clearly says that you hear the distortion but just don’t care because “This is low cost CB...... “

I have been into CB off and on since 1977, the first CB I that I owned I had to repair before I could use it. I am an electronics technician by trade, I have repaired a variety of both consumer and commercial electronics. That being said, yes, I do have an oscilloscope (2 actually) and other equipment on my bench for troubleshooting and alignment. I have always felt if I was going to do a job I might as well at least try to get it right, even if it is “low cost CB”, its called integrity, but if it’s being anal retentive so be it.

In closing I would like to again point out that all I had originally done was to offer up a tip to increase modulation without clipping the diode.

Thanks for the warm welcome…

 

[slprydk]

I have never heard a standard single final CB radio sound distorted by clipping the limiter..........never.

I have.

 

[slprydk]

It is better to alter the limiter than to eliminate it altogether, as a rule.

If you still feel you need more modulation after you adjust VR4, remove C71 and replace it with a 33uf 25v capacitor (make sure you get the polarity right). I never liked the idea of clipping the diode...

I thought that was what I was originally trying to do.