peaking a cb radio

Yes I can take a cobra 29 and take the cover off and do a few simple adjustments. Have no real clue how it sounds unless I am talkign to someone at the same time. I have no clue if it is splattering across 4,5 or 10 channels but hey I can do it. And no I don't go clipping anything.

Just google cobra 29 mods.

If you want a super tune then just cut D11 and remove the slugs under the wax covered tuning coils and stretch out the horizontal coil near the antenna port. When you get complaints then send the radio to Sparkies or Doug at custom cb radios.com and have it done correctly.

I think doug charges about 20 bucks for a peak and tune. Not sure what Al (sparkies) charges since he usually does it for free if you buy the radio from him.

 

That's the problem. When you start cutting the limiter diodes, it makes the radio sound distorted. I don't know of anyone who enjoys listening to a splatter box radio. I know I don't. IMO that's as bad if not worse than the fool who runs his echo up so much he steps all over his own transmission. I'll take clean clear audio over power any day.

 

A basic peak and tune does not require a O scope.Would it be better with a scope? Sure it would but Its not a have to and since we are talking tuning with AM use in mind and not SSB, where flat topping is more of a concern then AM (unless your running larger high powered stations,we are talking your average barefoot radio here) a scope is not needed to have a clean sounding radio,IF you do the P&T correctly and pay attention to the meter readings. If you tune one with out ripping the modulation limiter out ( it is needed regardless of what ANY cb tech tells you!) Set the final bias to spec ( duel final,export radio) dont do any of those stupid hack shack mods like swing kits and run a dead key of 5 to 10 watts set at 100% modulation as shown on the meter then you will not be over modulated or distorted and still be loud and proud!

The only time you run into distortion or over modulation problems is when you clip the limiter.turn the gain on the echo board wide open,run a low dead key,install a swing/mod kit,spread apart the little copper coils that are in the back back of the radio and dont bother to tune the final bias.Then your going to sound like joe blow super trucker! If you follow CB tricks info and take your time then this will not be a problem.

Most of the time a muddy sound comes from poor mike choice,not all radios like the same mike so play around with them, to find out what the radio likes best. Distortion comes from a really low key and or a poor tune job or BS mods. Peak power divided by 4 is what one would use to know what to set the dead key at to have 100% modulation. Say 35 watts is the peak reading then you divide that by 4 which comes out at 8.75 watts. Set you radio at 8 to 9 watts and with the correct mike you WILL ALWAYS have a clean crisp and strong signal,always!

A lot of you dont understand that the vast ammount of power you see on a peak reading meter is over modulation,distortion and harmonics,not true power.You dont want to hear that and you sure as hell wont hear a CB tech tell you that but the way it is, is the way it is. If you tune a radio using the average setting rather than peak setting on a meter then you will see that after about 4 to 5 adjustments inside of just about any radio your not going to see anymore power out of the radio regardless of what you do unless you do mosfet upgrades or volt the finals ( BOOM!). But on the peak setting of a meter the more you turn those screws,to a point.The more power your going to see but that is not true power,its harmonics which causes a peak reading meter to show more power.

Don't believe me? the next time you do into your fav CB shop have them to show you a 50 watt cobra 29 on the average power setting and not peak. They CANT do it and odds are they WONT even try!

 

I have read the numbers claimed,heard the radios on air and have looked at the mods that are done and what they look like on a scope. Radios are loud and proud all right,look at em on a scope and you will see why.
You know what people say about opinions right? Well,i just farted

by the way.....


Merry Christmas everyone!!!!!!!

 

Cuting the limiter is at best risky ......

 

I just dont know why anyone thinks they have to do this.If you turn the modulation adjustment all the way to the right then your going to have the same affect! You know why 95% of people/techs do this? Cause they are to lazy to do it the right way,the other 5% just dont know any better!

 

About 3/4 counter clockwise is all that is needed and sometimes that is a bit much if the person is a loud talker or uses a crappy powered mic.


The only radios that I have ever adjusted the limiter to 3/4 or a tad more are the drivers that I run with that are quiet talkers and hold the mic an arms length away.


The idea of peaking and tuning a radio is to get the radio to were it was designed to be as far as performance. As with all mass produced products, no two radios are the same. Some come out of the box doing great while others come out of the box barely able to make it across the median.

We have drivers with box stock radio that do great and sound wonderful while we have other drivers with the same setup that you can not hear for ####. These are the drivers that I aproach about getting their radio tuned a bit. The ones that have great working setups, I tell them that there is no need for it because theirs works great.

Peaking and tuning is not about opening up a radio and replacing a bunch of stuff and turning a bunch of pots etc to push the radio to its absolute limit. It is just about making the radio do what is was supposed to do in the first place. IE fixing the sloppy workmanship that you see in mass production.

 

And to do this you have to get into the radio and turn a few pots to get the max performance out of it while still being clean,make it do what it should do in the first place. In some radios you do have to replace a few things to get it where you want it. The Cb shop out in Ontario CA took out at least 10 different small parts out of my 99 and it sounds and works better than it ever did before,yet its still clean and not over modulated.

Its all about what you want. A basic P&T you can do your self. A full blown upgrade to get the absolute max performance from a radio,such as a clean receive,completely on freq for SSB use without drifting,change in the audio parts to get a fuller richer transmit sound,Mosfet upgrades on a SSB radio.so forth and so on require the scope,signal generator,multimeter and so forth.
All depends on what you want or need and how much your willing to spend to get it.I prefer to save a few bucks and do it myself,if i cant i take it to someone i trust. Problem is you cant trust 98% of cb techs!

 

So let me get this straight, you peak and tune your radio without the use of any real equipment. You know that is about the same as some of what you would see from some of the clip and snip type shops.

Then I could run down to the local TS and pickup a sheap power meter and start peaking and tuning radios for money????? Wow!!!!!

I would love to see you go into a competent CB shop, pick out a new radio and sit at the counter and P&T it then put it on the air with the shops radio that was done using proper equipment and see which radio does better. Kind of a Key down with just two barefoot radios.

Then let the shop put a swing kit in his radio and see who gets more roses on the air at any distance.

I wish christmas had not broke me because I would have put up the money for two matching in the box stock cobra 29 LTDs and paid the shop to do the P&T on his.

 

I promise you. You let any shop do the same old tired useless mods to their radio and then let me do the CORRECT ( few ) mods to the same radio and that CB shop would end up wanting to buy my radio just to see what was done.That has already happened more than once! Your still following the CB shops BS that you have to take any radio to them to have it tuned. If you have a clue and take your time you will do a better job than 98% of the shops you find on the road. It takes more than just power alone to have a clean sounding radio! Now if you want to wast your money on Joe blow CB tech then by all means go right ahead but i promise you that all the claimed power numbers that you see on their screwed with (cheap) meters are false.

.........i still remember the CB tech out in little rock that thought,after hearing me on the air, i was talking SSB on a true ham rig, he flipped out when i pulled the radio out and he saw that it was just an old Uniden Grant XL! Or the trucker who thought that i was running a big amp,it was a barefoot PC76! It's not what you use to tune a radio,its how you tune that radio that makes all the difference.

I bet you also think that an amplifier is supposed to make you louder to!

This is from my site,a little info to arm yourself with.

Over modulation is a result of running a low key which produce harmonics that cause bleed over,this is not caused by power. Excessive harmonics cause ANY peak meter to show power that the radio is not really producing because a peak meter can only read harmonics as power. Which is why you see such drastic decreases in power reading when you check output on the average setting of any meter. CB shops dont do this because they dont want you to see that everything that they do to radio,with the exception of larger finals or mosfet finals do not increase power,only distortion and over modulation.

You will also see cb shops spreading those little copper coils apart.This does not increase power,only harmonics. I knew a tech in Conover NC that went by Triple R that would show any export radio doing over 125 watts on a peak meter,and it did. But the very same radio,because of all the excessive harmonics produced by the radio,it would actually transmit on more than one channel!