How To install A Super Modulation Kit in a Cobra 29

[SaddleCat1]

I also did the "Cobra 29 Chrome" mod. You take a piece of 1200 grit emory cloth (wet) and go over the top panel (just above the front controls) until there is just bare plastic. This lowers the inductive coupling between the VFO and the RF buffer stage. This allows the buffer to apply full drive to the RF driver transistor, raising the overall dead-key output to about 15 watts. Add this to the Super Modulation kit and I get 115 watts modulated.

[SaddleCat1]

I experimented with this mod and found I could put a 420 uF cap., and a 680 ohm resistor and got 12 watts dead key and 60 watts modulation. I'm very happy with it!

[jeremyarnold1979]

i talked to a cb shop and he said not to install this mod on a 29 because this will put about14 watts to a 5 watt final is that true?

[cbman96]

what type of meters are below the astatic meters????

[piratefueljim]

I did this install but , I have 1watt dead key swings to 10watts. when the gain is all the way up it is a 2watt dead key swings to 10watts. Whats wrong? I did not turn anything up on the power side what would i turn and how much. I have a radio shack swr and meter.

[jmh47slc]

Check your mic.

[MrBuckwheat01]

I did this mod as well! I'm running a 470 cap with a 68ohm! Sometimes I don't have a dead key and sometime I do! Anyone know whats going on I lose my receive as well

[paraglidermx]

I would squeeze those coils you spread back to where they where,,I found you loose power when they are spread,,plus if you gain a watt or two on some radios,,its only in garbage(spurriouse emissions)outside the band..wasted power. Also a 470uf with a 68 ohm gives the best audio quality IMO.

577 Tomcat Jersey ;-)

[boricua6326]

great video

[bluejay148]

will a 25 volt cap work what will it do on a 25 v cap

[ChopperTCB]

@bluejay148 220uf (16-25 volt) electrolytic capacitor (the 470uf version will also work and people have also used a 1000uf version) you will not be able to tell much if any diffrence

[bluejay148]

hi ok i know the capacitor only goes in one way i was just wondering about the resistor it self thanks for the info anyway can you do one for the dominator modulator like to see a video on that plus how to install a receive upgrade kit and etc

[bluejay148]

hi which way the resistor goes im sure theres a positive and a negitive on the resistor

[ChopperTCB]

@bluejay148 the Cap - side goes toward back of radio the resistor has no - or + side

[zookie85]

boy i wish it was that simple to do a tune, it would be real easy for a do it your selfer...Too bad you need multiple expensive tools to work on electronics. And a MFJ or Dosey dont count...

[MidnightRiderMD]

This may have been a good mod 20 years ago, but it's mudduck stuff now.... The Mosfet mod does not gain enough to make it worth while.... And if you dont know what your doing inside the radio, leave it alone.... tweaking and tuning without proper knowledge and equipment only causes a splatter box! Good tune here for your typical truck driver or everyday joe!

[paraglidermx]

@MidnightRiderMD So just put an rfx-75 on it then bud.

[1219548tom]

the mod works great on uniden pc 68

[paraglidermx]

Are u using a dummy load?

[paraglidermx]

Awesome vid man!!!Can u make one showing how to tune and peak all pods??Please bro,I subbed ans friended.

[oldredneckranger90]

Do you think it would matter if i used a carbon film resistor? thats all i could find on the radio shack website. and all i could find was a 35v 220 micro f cap would you recommed that?

[ChopperTCB]

@oldredneckranger90 Not really sure about that I would stick to the Parts listed in the video you can pick them up cheap on Ebay 73's

[oldredneckranger90]

@ChopperTCB Alright man, I figured Ebay would be my second option. I also went to yahoo answers and looked around they said that a 35v could be substituted for a 16-25v, as long as you don't go under your fine they also said it will extend the life of the cap

[TheDefpom]

Dont forget to check radiomods.co.nz for mods, alignments and other CB information.

Adjusting the inductor can get more power, too much swing alone creates splatter and distortion, proper modulation settings should be done with a scope.

[pepsi3420]

i want be running my cb with a amp so that means i do or don't have to cut the rf gain wires.

[ChopperTCB]

@pepsi3420 as long as your dead key is around 2watts or so you should be fine without installing variable power

[pepsi3420]

can i use this up grade on a cobra ltd 25 or did i just waist my money buying it.could had got the 29 for 10 dollars more but didn't know much diffrent between them until after i bought it. is the 25 still a good cb

[ChopperTCB]

@pepsi3420 I prefer the 29, but I think this mod can be done on the 25 check the link in my description it tells

[pepsi3420]

can i use this up grade on a cobra ltd 25 or did i just waist my money buying it.could had got the 29 for 10 dollars more but didn't know much diffrent between them until after i bought it. is the 25 still a good cb

[ty6784]

so does this help the transmit and receaving

[ChopperTCB]

just TX

[OxGxDirtbagg]

Okay so maybe I am an idiot, but I don't see which knobs or how much "tuning" was done...can u walk me through that?

Like which knobs and how "wide" ?

Thanks!

[ChopperTCB]

you can either turn VR4 wide open or cut D11 for the Modulation(I recommend just turning the pot instead of cutting anything. The AM power adjustments are L12, L13, L14 you may have to do some trial and error to get the best forward swing hope this helps

[rmx77]

i have the same cobra 29. what i did with mine is i took off the limiting resister or capacitor or whatever u call it. i have been lookin for ways to increase my sending and receiving for it since i live in a hole and don't get much reception other then people that have cb's that are near where i live like right on the main road next to where i live up to a certain point cause anyone on top of a hill or farther down the main road i cant get them at all and they cant hear me. been lookin into it

[allenward69]

you can find that final on my website its used in the galaxy radio's you have to remove a few caps and add some resistors but peace of cake

[ChopperTCB]

Thanks I will check it out

[allenward69]

you should get the mosfets you can throw them mods in the trash now a days

[ChopperTCB]

no doubt but this is a 5.00 mod

[allenward69]

yea but mosfet mod increases modulation and power to do almost the same thing your doing here basically if your doing all this work and not replacing the final then really all your doing is a swing mod. with the mosfet mod you dont do that already had alot of modulation over 100% with leaving the mod block:)

[ChopperTCB]

do you replace the driver as well? What Final do you Use?

[cocoloco1105]

kool

[MrMladafronta]

I understand that same thing is possible in Uniden 76xl? Or am I wrong?

[neubie182]

@MrMladafronta it will work fine.

iv done this on cobra 29 and cobra 25, uniden 76, 66 and 68. works nicely.

also, variable power works on all too.

[MrMladafronta]

Ok mate but in uniden 76 are different markings than on cobra's board. What jumper is to be removed? My board is slightly different then one showned on the footage. This confused me so I postponed doin this mod.

[neubie182]

@MrMladafronta in a uniden 66 and 68 its jv17.

in uniden 76 and 78 jv101.

had to get my radios out to check this, but iv done this mod to all of mine and it works flawless.

good luck!

[ChopperTCB]

Nice info to know Thanks Nubie

[neubie182]

no problem. :)

[baddasschevy]

i have a cobra 29 ltd classic but after i have on for a couple min it dosent key up like it should

[larry40m]

I did this mod. now one can here me. Change it back to stock and still no one can here me. I guess I don't kiow what I'm doing.

[ChopperTCB]

hmmmm... well you have to start somewhere that is how i learned. did you install the cap with the - side toward the back of the radio? Check that all your solder connections are good I'm not really sure if you put the Cap in wrong it may have damaged something

[LuC1Fr]

Haha, thats true i remember when i repaired one of my dads radios, the power supply coming into the radio was loose, just a simple soldering job to get the wires back on the board, Fired it back up and a puff of smoke.. Got lucky though, it was a small enough short it melted the solder at the joint before it caused any damage.

[RustyCarnahan]

Do you have any idea what a bigger capacitor would do?

[ChopperTCB]

nope i just followed the instructions

[larry40m]

Tried again. One of the solder points didn't have a good connection.Thanks to my brother who had a closer look at it. The radio is good .Sounds great.

[ChopperTCB]

Good Deal Glad you got it fixed! Sometimes Small problems like that can be hard to find 73's

[dr07828]

You did it wrong and put the cap in backwards and blew your final.

[AK47cowboy]

i had this done to my cobra 29 chrome in nashville. the guy said it was doing 35 watts. is that pretty decent for whats been done to it?

[ChopperTCB]

yeah it's Real Good I usually get between 25 and 30 watts out of one with stock finals after installing this kit and tuning the Radio, But it Really Helps the Modulation and is a cheap Modification

[dr07828]

loose meter.

[wesmckay]

I have always found that using a 47uF 25V capacitor gives me the cleanest audio. I love the way this kit responds in my 29.

[ChopperTCB]

thank you I wish I had had this video when I was learning this mod, But I hope it helps someone else

[VictoreCelia]

very nice