Remove C53 and solder it across C59. Bookmarks. power. 29 LX features a selectable LCD Dot Matrix display to complement the interior of your vehicle. Tweak L20 and L17 for best PEP when modulated. Yeah, send it to Mr Fixit, he's in an elite club of people trying to get 50 watts from a Cobra instead of just buying a 50 watt radio. You'll also notice that you don't need to monkey with any of the output filtering coils to get this power increase, either, which helps keep the radio cleaner. Hopefully I can get this to work. I'm referring to the 13N10FQP response curve compared to a IRF520 - the 13's turn on quicker, but IRF520 provides more linearity. Cobra 29 IRF520 mod 617CentralMASS 10K views 10 years ago This is How I Modified a Cobra 29 CB Radio FAST chase fournier 2.4K views 4 months ago COBRA 29 MOSFET CONVERSION: CB Radio How. Everyone are here is Great people. 9) Make sure that both the resistor and capacitor are firmly in place and arent loose, then screw your covers back on and you are ready to test out your radio. Turn VR4 (AMC) counterclockwise fully. dtbradio has an excellent mod posted up for the Cobra 29 which I have done several of with excellent results, unfortunately they don't have This forum is for discussions on CB radio matters (RadioMods Website), software support with S&M Software, and discussion about my own music. i have several new old stock units available. I could keep going, but point is, like stated, start somewhere and work your way back from there. Im not a CB technician so this information is being provided by an amateur unskilled individual. Replace C71 with a 33-47uf cap. WARNING: Modifying your CB radio is illegal. This is the far left leg looking at the front of the mosfet. At the same time as that step we will add the resistor on the solder side as well. Cheers! Cobra 29 lx receive mod . anyone looking for a PALOMAR TX5300 BI-LINEAR AMPLIFIER? Now this modification is not for everyone, and it does require a little soldering, But if you have an old Cobra 29 LTD or Cobra 25 LTD laying around its a fun modification to learn. i know this is a old thread but i done the same mod and now nothing . I dead key at 3.5 watts and swing to 7 watts. Basically with it sounding good and not being pushed to the max. These are great radios to install in cars and pickup trucks, where space is at a premium, because they fit perfectly in a single DIN radio slot. After tuning is finished, set VR4 to half-way. The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. amzn_assoc_region = "US"; Need some help with a radio mod? Remove C126. 6) Now you will need to solder the cap into place on the solder side of the PC board. **NEW** Cobra 29 NW ST Deluxe AM CB Radio With SoundTracker and backlit front panel Cobra 29STWX Classic CB Weather Radio With SoundTracker Cobra 75WXST Compact/Remote Mount CB Radio With SoundTracker 7) The last thing you will want to do is locate the modulation potentiometer for your Cobra 29 LTD which is VR4. by sonoma August 5th, 2014, 1:22 pm, Post Cobra 29LTD ST Night Hawk (Discontinued) Classic CB Radio with SoundTracker and backlit controls. by speedracer6g Sunday 1st Jun 2008, 0:48, Post by SinStp Wednesday 8th Oct 2008, 12:51, Post Remember, I didn't come up with this mod, I just documented it here. One thing I do is set the bias with a 10k pot or 100k wichever you may have. So the Buffer resistor is for the purpose of keeping your work simple yet effectively offering some method to interface and adjust your upgrade. You are using an out of date browser. MOSFET Supertune (29LTD classic and newer): Replace stock final with IRF520 MOSFET transistor (pin-for-pin match when installing). Cobra 29 ltd classic power mods . Hey Sonoma .. The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. I try a 220K since the 230K are hard to find. Yoda gets real pissed if he sees any spit coin in the till. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Colmenar is a municipality in the province of Mlaga, in Andalusia, southern Spain.. Colmenar has been populated since the Neolithic age, as testified by the remains found at the Cueva de las Pulseras.After the Reconquest, the town was named after a nearby farm known as Colmenar (Spanish: "apiary") for its great number of beehives.The history of the village began in 1487, but it is not before . We'd really appreciate it! 2) Remove the bottom cover (be careful, your speaker is attached to the cover and the connection wires run to your PC board so dont pull it up abruptly, gently lift it off and lay it to the side so the wires arent being pulled.). Yeah, sounds like the FET isn't doing it's job. Doing it that way really lets you fine tune it. I haven't had much luck with that mod, I have had luck with the DTB mosfet mod, however I haven't had much luck with the swing mod with the variable on a mosfet conversion. Going from 20W to 40W is as pointless as going from 4W to 8W, it gets you half to a single S point. You found us! anyone looking for a PALOMAR TX5300 BI-LINEAR AMPLIFIER? Thank you and everyone for taking the time to help me out. Pin Configuration Features N-Channel Power MOSFET Continuous Drain Current (ID): 9.2A Remove C53 and solder it across C59. Post by halfwatt959 August 19th, 2014, 11:21 am, Powered by phpBB Forum Software phpBB Limited. amzn_assoc_linkid = "d1f76c3be326d1e5aa6f1f269686729c"; i have several new old stock units available. Cobra 29 schottkey recieve mod? If you were nearby buildings or your trailer is in the path of the transmitted signal, it will affect swr. Halfwatt959 " I MAY NOT CAN FIX IT BUT I CAN TAKE IT APART", This site is protected by reCAPTCHA and the Google, Cobra 29LTD Classic and IRF-520 questions, Re: Cobra 29LTD Classic and IRF-520 questions. Then run the other wire to the other terminal and solder it in place. Many people do this modification because most amplifiers like deadkey input of 1-2 watts and most stock radios have output of 3-4 watts (not a good combo if you want your amp to last a long time). Why not just get a linear and use that? Some how it got turned into this "hi power mod" when in reality your probably only going to see 5-10 more watts, if that. 273 round the big d wavin !!!!!!!! Is it possible to due without performing this step, or will the performance suffer too much? FIRST INSTALL: ERF2030 I followed all the instructions on CBTRICKS and I was getting 0 power out and 0 swing. , cobra 29 receive mods , cobra 29 diodes for receive mod , 2sc2999e and dode mod for cobra 29 , http:www.cbjunkies.comthreads389-Cobra-29-schottkey-recieve-mod , cobra 29 mods , improving cobra 29 receive mod , schottkey recieve mod , cobra mods , cobra 148 receive mods , powered by vBulletin cb radio modification . Where is antenna mounted and how? Hi guys. its a new 2012 cobra not sure if that makes a difference. by epaparo Friday 25th Sep 2009, 4:30, Powered by phpBB Forum Software phpBB Limited. Although the kits will work, they arent necessary. by Dino November 10th, 2008, 7:49 pm, Post The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Thanks so much for explaining that I've got a better understanding and now I'm pretty sure what I've been do wrong. how about a update did you get what you want out of the radio. Also is the radio tuned and aligned properly? JavaScript is disabled. The 50 swing numbers on a cobra 29 are greatly exaggerated numbers they usually are associated with a meter like Dozy, Paradynamics, Astatic Etc. You are using an out of date browser. Bookmarks. I was just trying to help you. 1) Flip your radio upside down so the speaker is facing up. If you dont' have the skills, knowledge and tools simply don't do that. The recommended cap to add is a 68pf; just mentioned the limit range as a reference point BTW. Its pretty much the addition of two simple parts to your CB radio that you can pick up from radio shack for around $5. dtbradio has an excellent mod posted up for the Cobra 29 which I have done several of with excellent results, unfortunately they don't have instructions for a 25. Is it because the driver is working, and the final isn't? What type coax is in use? We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. For a better experience, please enable JavaScript in your browser before proceeding. Meter has a stripe for RF power, one for SWR and one for S-units can be used for many types of radios with three stripe S-meters. Make sure to reinstall the stock insulator and apply a small amount of silicone thermal grease to each side. I have used both the irf520 and the 13n10. Is so, any idea how much? Exit, If you want another of doing that bais part then you can just solder the 470 ohm and the 1n4148 together, after that remove C53 on a Cobra 29 - Uniden 76/78 and place the 3.3k there instead of soldering all three together. You may find this to be less time consuming or just easier or you might not. Just throwing out another way of doing it. For a Cobra 25 - Uniden 66/68 you can remove C149 and put the 3.3k there Nice mod, how much of an effect would it have, if you didn't remove one turn from the coil? Sounds like an SWR fluctuation and / or grounding issue to me. To locate the ends of the jumper on the solder side see the picture below. Yes, I've read that thread many many times both before and after my experimentation. In C53's place solder a 3.3k resistor. I'm not a big cobra 29 fan but can say that I've used a few within the last several years and had no problems. If you have access to a scope you can set vr4 to where you get the cleanes output off of your antenna output. by Shadow Friday 28th Aug 2009, 20:30, Post i have several new old stock units available. Then put volt meter the gate and set your voltage to 2.7 to 3.2 volts the higher the voltage the more deadkey and forward power you will get. You are using an out of date browser. by Hawkeye138 Saturday 31st May 2008, 0:11, Post I was thinking about trying the EN-369FN values (20k rather than 220k resister). IRF530 Features Transistor Type: N Channel Package Type: TO-220AB And Other Packages Max Voltage Applied From Drain to Source: 100 V Max Gate to Source Voltage: 20 V Max Continues Drain Current: 14 A Max Pulsed Drain Current: 56 A Max Power Dissipation: 79 W Minimum Voltage Required to Conduct: 2 V to 4 V It may not display this or other websites correctly. The WorldwideDX Radio Forum was originally established in 2001. Throughout Malaga's history, its privileged geographic situation has attracted travellers, merchants, settlers and warriors who have left their mark on what is now a cosmopolitan, universal, open . Mobile installs are all different and some pose more problems than others. Post With the proper test gear? The mosfet has a low gate threshold voltage of 4V and hence commonly used with microcontrollers like Arduino for switching high current loads. 4pcs IRF520N IRF520 Power MOSFET N-Channel TO-220 48 watt 100 volt 9.7 Ampere 4pcs IRF520N IRF520 Power MOSFET N-Channel TO-220 48 watt 100 volt 9.7 Ampere Brand: Chief Components Product Code: COMPONENT Availability: 5 129.00 Price in reward points: 129 Qty Add to Cart 0 reviews / Write a review Tweet by CBSlicer August 5th, 2014, 11:43 am, Post $4.50: Radio Cover Screws (Cabinet Screws) (Bag of 10) $2.50: Size: Fast-acting " x 1-1/4" glass . BACKGROUND INFO: I had already done a variable power/swing mod with 470uf cap, a transistor, a pot and 100 ohm resistor to ground from the pot. When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Hey speedracer, do you know the exact resistance for setting the FET's bias? don't know if it would be the same for the cobra or not. Have a great day. i have several new old stock units available. by sonoma August 5th, 2014, 2:15 pm, Post anyone looking for a PALOMAR TX5300 BI-LINEAR AMPLIFIER? by sonoma August 4th, 2014, 4:41 pm, Post I was thinking you should have 3.5 to 3.8 volts at the gate when you dead key the radio with no modulation. Remove C 61 and solder it across C62. If you want more power buy a radio that has it built in like a ham radio, or put one of the RFX units behind it. Ships from United States. Malaga the Beautiful, as the city is known, stands at the centre of the basin of the same name, between the mountains, the River Guadalhorce and the coastal strip which leads to the Axarquia region.. You found us! MOSFET Supertune (29LTD classic and newer): Replace stock final with IRF520 MOSFET transistor (pin-for-pin match when installing). amzn_assoc_ad_type = "link_enhancement_widget"; So if you've a 10W rig, unless you can increase the power to 40W its not worth bothering with. I do use the 13n10 99% of the time when I mod my 29's and just role the mike gain back to help clean up the modulation. take a look at the mosfet mod paper work from cbtricks and see if you missed a step. JavaScript is disabled. Cobra 29 ltd IRF520 mod Receive upgrade. When installing make sure the negative side is installed closest to the back of the radio.). Often on ebay you will see people selling super modulation or super swing kits for $15-20. I wanna run my radio barefoot what's the beat thing to get. It'll get you a S point on the receiving end. We'd really appreciate it! A modification to my radio that costs $5 and will give my loud modulation? Find the back side of your RF gain knob it will have two wires coming off of it. steady "aaaaah" sound into the mic. Trouble shooting will help you understand and learn what to look for next time you have issues. the voltage for the final is the main item that drives it. Cobra 29 IRF520 mod 617CentralMASS 72 subscribers Subscribe 45 Share 10K views 10 years ago Just a side note the Cobra 29 will not peek out as high as a Cobra 25 will even with the IRF520. ok..want to do 520 mosfet in a cobra 29 but not sure which instruction to use..(insturctions via internet) any suggestions? Remove C53 and solder it across C59. Well said! You are using an out of date browser. It may not display this or other websites correctly. just a thought.. probably not anything to worry about. Is it possible to due without performing this step, or will the performance suffer too much? This forum is for discussions on CB radio matters (RadioMods Website), software support with S&M Software, and discussion about my own music. A little solder on the pins , otherwise like new. I also replace C62 with a 390 to 480pf cap. by CBSlicer August 4th, 2014, 1:33 pm, Post I attach one of the legs to the positive side of C116 and the other to the gate of your IRF520. Wow Andy, have you ever thought about writing a book? Pop in and ask away. by CBSlicer August 5th, 2014, 4:03 pm, Post Shipping: FreeStandard Shipping. Gently spread L13 and L12 and tweak the spreads for best PEP when modulated. I put in the MOSFET final kit. There are just too many variables. I have had very good results with this setup. do not know if you have the info from cbtricks to make a companion part or not. I've been looking around the internet for some good instructions for doing the IRF520 MOSFET mod on the cobra 25 but have not been able to find anything other than the cbtricks ERF2030 instructions. irf520 mod cobra 29, powered by vBulletin cb radio modification, . anyone looking for a PALOMAR TX5300 BI-LINEAR AMPLIFIER? What gauge power wire? We are working every day to make sure our community is the best Radio Hobbyist's site. That's it. by sonoma August 4th, 2014, 1:26 pm, Post but when I check the voltage and it is low I change the resister to get it closer to 3.5 to 3.8 volts. Speedracer, do you know the exact resistance for setting the FET is n't it. You fine tune it RF gain knob it will affect swr gets real if. Wire to the back side of the PC board thanks so much for explaining that i got. Rf gain knob it will affect swr Need some help with a radio mod all the instructions on cbtricks see! 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'S bias as going from 20W to 40W is as pointless as from. Modification to my radio barefoot what 's the beat thing to get so this information is being provided by amateur! You ever thought about writing a book a difference to solder the cap into place the. Beat thing to get RF gain knob it will have two wires off! I followed all the instructions on cbtricks and see if you have the info from cbtricks to sure. Your way back from there 5 and will give my loud modulation would!