How To Add Talkback In A Cobra 29

Been reading mod pages about calculation talkback by jumping PA and EXT SP, Just thinking if this is washed then the PA would be unusable for connecting a PA speaker. Am I right? Would similar to add together talkback and repeat.
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Rat Road Train Member

Do you lot use a PA speaker alot?
Hither is a thought, discover a old cobra 29 that has other issues. Open it up and take the on/off and volume control out of it. Open upwardly your working radio and remove the RF proceeds control knob. Solder the RF gain wires together and estrus compress them. This sets the RF gain at wide open.

Now identify your extra on/off volume control into the RF gains spot. You will have to go your ohm meter out first to figure out which terminals yous demand to utilize to turn the talkback on and off as well equally have volume command of the talk back. Should not be too hard to figure out. Now run a wire from each of your chosen terminals dorsum to the ground sides of the PA and the external speaker. Solder them also the board and blast you are done. You know have talk dorsum you can turn on and off also as being able to control the colume of the talk dorsum. When you want to use your PA then you merely plow the talk dorsum off and use your pa as normal.

I feel it is important to have a variable talk back and so that you can control the volume of it or you might stop up with a abiding squeel due to feedback through the mic.

Or go buy one of the cobra models that already has talk dorsum in it. I believe both the archetype chrome and the black chrome models have talk dorsum already setup from the factory.

As far as the ECO, not sure why yous want it. Waist of money in my stance. the majority of the people don't care to listen to eco and I take yet to find were any amount of eco really fabricated a radio sound better over the air. Most of them sounded 100 times better with the eco completely turned off.
Well you know Channel Jumper, if you don't have echo on your radio, you're not cool. Just ask some truck drivers.
I accept the echo and talkback turned off in my radios. I call up well-nigh that accept to have echo and talkback just similar to hear themselves talk, it makes them feel important and they remember they're trucks go faster with it.
fsthawk I am sorry that on your commencement postal service to this site you have to be treated so poorly. I know y'all did not deserve to exist berated for wanting to add talkback to your radio (or in full general even being so stupid every bit to run a CB), past a bunch of ham operators almost of whom have never fifty-fifty driven an 18 wheeler. Hopefully yous volition not take this poor treatment of your desire to run a CB radio in a truck on the CB department of a truck driving website past a group representing ham radio as an example of all those who do have a ham license. I have no thought why this site is the most poorly moderated board on the internet but there it is. Thread after thread, post subsequently post everywhere on this forum the aforementioned thing goes on past mostly the same group of people. Every time a person innocently asks for advice the thread is hijacked to drive the topic in the same management, namely:
1- ham is better than CB
2- y'all are a fool, a child, trailer trash, an ignorant moron for not knowing how much improve ham is than CB
3- nigh no i will endeavor to help respond your question
4- run a repeater, utilise 2 or 10 meters, surely the loading dock will hear yous, surely you will exist warned past other drivers on the route nigh hazards or conditions up ahead if you volition only throw abroad your CB and become ham
v- use your cell phone surely all other drivers have your number
6- I could go on but what is the point
If this is how ham operators set a shining example to others of what a great hobby it is, no wonder the numbers are dwindling and the spectrum space is beingness sold to big business by the government.

Not caring for the despicable treatment of poor innocent unsuspecting souls who dared to come to this site and enquire for help for their CB, and the endless hijacking of threads by people defended to impressing you with how much meliorate they are than y'all I volition try to help. You can connect the grounds between the external speaker jack and the PA jack with a fixed resistor ranging from 22 to 150 ohms. The value will exist determined by your radio model, choice of mike, and other weather condition such every bit speaker type and placement. You volition need to decide this experimentally to go the correct level of talkback and no, it will not touch your use of the PA function. A typical example for a dissonance canceling mike on a Cobra 29 would be to start around 68 ohms. For a stock mike effectually 100 ohms. Listen to the sound and go from there. Use a resistor rated for at least 1/4 watt. If y'all have to lower your mike gain to stop squeal y'all are likewise loud, get to a college value resistor and so every bit to not excessively reduce your transmitted power. Rat was giving yous a good idea except his choice of variable resistor is not all that optimum. A volume command is typically fifty,000 ohms, much too loftier. Actually the 1,000 ohm RF gain control already in there is a better choice equally you will have a wider range of adjustment in terms of degrees of rotation of the control. However I for ane prefer to accept the RF gain function so I believe picking the correct value of fixed resistor is a better method. As to echo I am kind of with Rat, it would be better if those actually using i would at least learn how to adjust it.

I have had many drivers over the years say talkback helps keep them awake during the long night hours over the road. Besides the nonstop motion to the cord makes them fail often and it is good that you can immediately tell when there is a problem with the mike cord, or the switch since plating of contacts is a thing delegated to history.
Rat Route Train Member

If you don't us the PA office and so yous tin get an external speaker that has talk back function. I bought one once. I believe it is a Cobra speaker. Information technology has a dial on the back of the speaker turns it on/off and also controls the volume.
AB7IF, I used a volume control once on an older radio and it worked but fine. The first radio I had that had talkback in it was a cobra 29 that I had the talk dorsum installed by a CB shop in Ann Arbor. He used a VR pot,much like the limiter VR. he installed it on the solder side of the radio near the speaker and PA ports. It worked fine just I had to remove the pinnacle cover to suit information technology to get rid of feedback. Finally, I marked the spot on the embrace and drilled a hole in the cover so I could go to it without having to remove the cover.

Every bit far as using the RF proceeds control, well many people just crank it broad open and never ever touch it, they perfer to apply the squelch to control noise. This is why I gave the option of removing the RF gain command or even using the RF proceeds control like yous suggested and which I have washed.

I am but nto big on installing a fixed value resistor. If it is too loud or not loud enough then you lot take to take it all autonomously and bandy out the resistor and keep doing this till you find the correct resistor for the enviroment in which the radio is going to be used and if and were he may accept an external speaker mounted in the cab etc.

There is some other option, Cobra radios go along auction all the fourth dimension at truck stops. Some of the cobra models have talk back already in them and it is variably controlled via a knob on the front end of the radio. I have seen them as depression and 100 bucks.

How nigh a double command or a command or what always it is called. Yous know similar some of the controls you see on some Uniden models. Were the heart knob controls 1 function such as book and the outer ring controls another function. Do you lot think in that location could exist one that has the proper values to be but in identify of the RF gain control and use that from both the RF gain and talkback? The center knob could control ane and the outer ring could control the other? This might be a better pick if nosotros had an idea what control would have the proper values.

I would non mind rehooking the RF proceeds control dorsum up on the one I did and use a double control so that I could also have the variable talkback.

I have an quondam doner PC 68 LTW sitting here that I could rob the command out of. One of them controls the mic gain and the RF proceeds via the center knob and outer ring. Would the mic proceeds department work for controlling talk back?
With a volume command (50K ohm) the talkback is all or nothing virtually one end of the range. Plus volume controls take a Log taper making it worse. A linear taper pot similar the RF proceeds of 1K is going to give you a more precise aligning with a wider range of rotation. 500 ohms would be meliorate still but not like shooting fish in a barrel to discover especially with identical mechanical configuration such as knurled shaft of proper length, and then as to keep the aforementioned radio knob. I have washed the dual pot before, y'all can find combos of 1K/50K that piece of work out OK, 50K being besides high for mike gain in some models just it will work adequately well. Likewise much mismatch over design values can introduce distortion in the audio. Hard to detect with switch combo making information technology harder to supercede the volume (single) in a Classic 29 to add together talkback there. A dual 1K to make RF proceeds a combo with TB is a good choice. Wiring RF gain full is not a good idea. If you just have squelch you lose range. It takes more betoken to trip if RF is total on. In average dissonance conditions you will find about 3:thirty on the RF gain, with squelch just at threshold gives you quieting yet someone can be 2 to 3 times further abroad and nevertheless break your squelch every bit opposed every bit a tighter squelch setting because RF gain is full on with no style to adjust. The ratio of the 2 settings varies with conditions which is why the engineers gave y'all both controls. Likewise only using RF proceeds to placidity the radio (many run it similar this) kills the receiver. A poor way to run a radio since the dynamic range has been wrecked by shutting the receiver off too hard. Your talkback speaker choice works too, my only problem is the quality of the speaker in nigh of them is and then poor.
" Thread subsequently thread, post afterward post everywhere on this forum the same thing goes on past mostly the same group of people. Every time a person innocently asks for communication the thread is hijacked to drive the topic in the same direction, namely:
1- ham is better than CB
ii- yous are a fool, a child, trailer trash, an ignorant moron for not knowing how much better ham is than CB
iii- almost no 1 will effort to assist answer your question
4- run a repeater, use 2 or ten meters, surely the loading dock volition hear yous, surely you will be warned by other drivers on the road most hazards or conditions upward ahead if you lot volition but throw away your CB and get ham
five- use your cell telephone surely all other drivers take your number
6- I could keep just what is the point
If this is how ham operators set up a shining example to others of what a nifty hobby information technology is, no wonder the numbers are dwindling and the .....................

spectrum space is existence sold to big business concern past the government

Sadly I take to hold some are posting things almost the "dumb " CBers ...

That said EXCEPT for 220-220 what bands have the hams lost since 1990 ? I accept been on 220 since 1974 and nevertheless am.
Almost are shaired like the 440 band some are HAM only ......

Once more that said I tin see microwave bands going by-by I have been on 1296 and up at 96 Ghz and there is non many to talk likewise ......

One practiced reason I did non spend $600 to put the 1200 mhz box in my TS-2000
For a long time many die hard Morse code advocates including the ARRL considered quality over quantity was about important. After loss of ring space and pressure past business to buy more room (at around a million dollars per megahertz), the 'use information technology or lose it' forces won out, thus the dropping of code standards. In outcome y'all might say further loss of band allocation was abated by surrendering the idea that if it was worked hard for information technology would exist respected more. Anyone tin can memorize questions specially when the answers are already known. Having to pass 20 WPM forced people to really work very difficult and therefore respect highly that which was gained. So you could say aught more has been lost but I for ane would not brag nigh since I think much more than was lost than many realize.
Well.....
My older blood brother passed his actress at xx WPM and loves code ..... I don't know what speed my younger brother did it at but both of the states took our Tech course at the FCC considering of a problem the FCC had with the local club and someone giving the tests back in the mid threescore's.
Except for my moodbounce days I have never used it now i endeavor and copy it but with my days starting at 4AM and never quiting to midnight Information technology has
been on the dorsum burner for 3 decades now. My FT-840 and FT-100D have CW filters I have many good keys like several J-38's and on a rare fourth dimension I accept petty to practice lissen to twenty CW there is little to match the audio of someone who knows how to send information technology right ......

I take worked at UHF/VHF since I finshed school in the ARMY and in many engineering or production places mainly on FM UHF but we had stuff going downwards to 26 mhz and up to 196 GHZ.

The Need for space is going to be above 400 mhz fiddling today is going to be in places that there are HAM bands and with the loss of Television set to digital
there is a lot of High VHF and some UHF now condign unused.

I do experience information technology was over kill to impale the code for all classes the extra would have been a place to have kept some kind of requirement but with the FCC in its land of mind information technology is in today and few HAMS in the FCC code is something even they don't empathise. Expect at enforcement the caput is not a HAM or CBer just another lawyer ....
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Last edited: Aug 23, 2011