20 Most Recent Cobra MRF55 2-Way Radio Questions & Answers

Try resetting the radio per the user manual by doing a setup procedure as described on page 28. This may clear up the problem. User manual here: https://www.cobra.com/sites/default/files/manuals/MRF75D%20-%20ENGLISH_0.pdf

A lot of times if you transmit too long, that can happen. And it eventually can result in blown finals, if you let it go long enough. Make sure your radio is also not transmitting continuously. It probably isn't, but both look at the display for an indicator (you could be laying it down in such a way that it will do that)...tune another radio to the same frequency. Sometimes a defective antenna will cause that, as well.

? I assume you are asking if you need an ariel antenna for this radio in order to receive and transmit? if that is the case then yes you do, Any radio requires a matched antenna in order to transmit, if you were to transmit without an antenna, most of the RF energy will transfer back into the radio and over heat "burn out" the output transistors. always make sure to have a proper antenna connected before transmitting on any radio.

Hi, I friend of mine did the same thing.
I can't tell you where to get it repaired but I can tell you what I found.
After taking the cover off and removeing the screening can I found a
diode had popped it's cloggs. Split open.
It's just by where the power cables connect to the pcb.
It's a 1N4004, 16p from Maplins.
I replaced this and the unit now works fine.
Hope this helps.
Dave.

according to FCC rules RULE 8 - Antenna Height
{A} "Antenna" means the radiating system (for transmitting, receiving or both) and the structure holding it up (tower, pole or mast). It also means everything else attached to the radiating system and the structure.
{B} If your antenna is mounted on a hand-held portable unit, none of the following limitations apply;
{C} If your antenna is installed at a fixed location (whether receiving, transmitting or both) it must comply with EITHER one of the following:
[1] The highest point must not be more than 20 feet (6.10 meters) higher than the highest point of the building or tree on which it is mounted;
or
[2] The highest point must not be more than 60 feet (18.3 meters) above the ground.
{D} If your CB station is located near an airport, and if your antenna structure is more than 20 feet (6.10 meters) high, you may have to obey additional restrictions. The highest point of your antenna must not exceed 39.37 inches (1 meter) above the airport elevation for every 109.36 yards (100 meters, 1 hectometer) of distance from the nearest point of the nearest airport runway. Differences in ground elevation between your antenna and the airport runway may complicate this formula. If your CB station is near an airport, you may contact the nearest FCC field office for a worksheet to help you figure the maximum allowable height for your antenna. I’m happy to help further over the phone at https://www.6ya.com/expert/william_83fc156eee2b555e

http://www.cobra.com/downloads/manuals/MRF75_manual-Eng.pdf.

Howdy from South Texas and Merry christmas.

Here is your link and enjoy the Holidays.

http://cobra.com/downloads/manuals/MRF55_manual-Eng.pdf

Patrick Patterson

A manual link is at the bottom of this entry. Troubleshoot the problems you've described: Meter Not Working: The needle moving slightly to the right when you key the mic could be due to incorrect calibration. Make sure to recalibrate the meter according to the manual instructions. If you calibrated it differently, that might cause the needle to go against the right side of the meter. Recalibrating the meter should resolve this issue. Meter Light Problems: If the meter light isn't working, consider replacing the LED. Sometimes, a burnt signal meter light can occur. Replacing the LED should fix this. SWR Meter Not Working: Incorrect SWR calibration or bumping the calibrated knob might cause the SWR meter to malfunction. To check the SWR meter: Turn on the SWR calibrate knob until it keys up all the way at the end. Switch to SWR mode and key the mic. If the needle barely moves, turn down the Dynamike knob. Finally, switch back to S/RF mode. No Receiving Audio: If you're not receiving audio, check the following: Ensure the squelch knob is adjusted correctly. Start with the knob counterclockwise and turn it slowly clockwise until white noise stops. Verify that the microphone is working properly. You can try a different mic to rule out any mic-related issues. Make sure the radio is on the correct channel for transmitting and receiving. ========================================== Calibrating the SWR (Standing Wave Ratio) meter on your Cobra Classic 29zLtd CB radio is essential for optimal antenna performance. Follow these steps to calibrate it properly: Prepare the Setup: Park your vehicle at least 20 feet away from trees and buildings. Close all doors, hood, and trunk. Choose the Channel: Select the channel you want to check. It's recommended to test on channels 1, 20, and 40. SWR Calibration: On the radio, press the SWR/CAL button until the display shows "CAL." While pressing the transmit button on the microphone, turn the SWR CAL knob (the last knob on the right) until the meter needle aligns with the "CAL" mark. Release the transmit button. Switch to SWR Mode: Push the SWR/CAL button again until the display shows "SWR." Read the SWR: Press the transmit button on the microphone. Observe the SWR reading on the top scale of the meter. Ideally, the SWR should be below 3. Lower values are better. Remember that SWR is a measure of antenna performance, and poor SWR can be caused by the antenna, antenna cable, or installation. Adjust the antenna length to achieve similar SWR readings on channels 1 and 40 while keeping it below 3. Most antennas are adjustable; refer to the manufacturer's instructions for specific adjustments. cobra-29ltdclassic-cb-radio-user-manual.pdf (roadtrucker.com) MANUAL

See page 11 of user manual MRHH600B_ENG_MANL_REV_01522_NO_SEATOW.pdf (shopify.com)

Question edited for clarity and translated into 'Adult'. Question moved from Cellphone category. https://www.google.com/search?q=cobra+rx385+no+audio https://www.google.com/search?q=Cobra+rx385 ..

There appears to be help here and that forum is the best place to ask. It is a Post Factory modification according to this.

WTB cobra 148 gtl side mic

WorldwideDX Radio Forum https://www.worldwidedx.com > threads > wtb-cobra-... Feb 27, 2019 - 148 GTL side-mic uses 5 pin mic receptacle. If the radio in question is a side mic and has a 4-pin receptacle, then it was put in post-factory ... Cobra 148 GTL Malaysia.. side mic?? Should I buy? Aug 13, 2018 148gtl blown d44 and mic Jack conversion - WorldwideDX Mar 1, 2018 Old school Cobra 148GTL.... ' WorldwideDX Radio Forum May 13, 2019 Cobra 148gtl Basket case! ' WorldwideDX Radio Forum May 7, 2018 More results from www.worldwidedx.com https://www.google.com/search?q=Cobra+148+GTL+side+mike+jack ..

Here are the instructions:

• PIN #1 ~ WHITE
• PIN #2 ~ SHIELD
• PIN #3 ~ BLACK
• PIN #4 ~ BLUE
• PIN #5 ~ RED YELLOW N/C

I hope this helps!

Download the manual from COBRA HH 33 OPERATING INSTRUCTIONS MANUAL Pdf Download ' ManualsLib

Question edited for correct make and model name. Try a reset and if that doesn't work, send it in for warranty repair.

Tutorial: How to Reset Cobra Walkie Talkies

https://www.walkie-talkie-guide.com > how-to-reset-co... So, how do you resolve it? One solution is to reset your walkie-talkie if it has factory default settings. After resetting it, the radio will go back to its ... ‎All About Cobra MicroTalk · ‎Factory Reset · ‎Why Reset It?

My cobra micro talk walkie talkie isnt working one - Fixya

https://www.fixya.com > support > t15390372-cobra_m... Nov 21, 2019 - If you have your manual, and it describes a way to do a "master reset" on the radio, follow the instructions. This usually involves pushing down on one key ... Why is there no audio on my Cobra MicroTalk radios ... 1 answer Nov 21, 2019 How can I fix a walkie that can not receive sound ... 1 answer Dec 4, 2008 SOLVED: Speaker in cobra microtalk - Fixya 1 answer Sept 2, 2019 How do I fix the sound on the cobra microtalk - Fixya 1 answer Aug 31, 2019 More results from www.fixya.com

FAQs - Cobra Electronics

https://www.cobra.com > frequently-asked-questions Have questions about your Cobra product? View frequently asked questions and ... CB Radio - Troubleshooting · Dash Cams · Microtalk Radios · Cobra Tag

Manuals in the link tell you how to tune. What kind of 'modifications'? https://www.google.com/search?q=Cobra+29+LX+max+manual ..

I believe to wire a Sadelta M3 microphone to a Cobra 29 LTD Classic CB radio: The Sadelta M3 microphone has four wires: white, shield (bare wire), red, and black. The Cobra 29 LTD Classic CB radio's microphone jack also has four pins: Pin 1 (Audio), Pin 2 (Ground), Pin 3 (Transmit), and Pin 4 (Receive). To wire the Sadelta M3 to the Cobra 29 LTD Classic, you need to connect each wire from the microphone to its corresponding pin on the microphone jack. The white wire carries the audio signal from the microphone's element to the radio, the shield wire provides a ground connection, the red wire activates the radio's transmit function when the microphone is keyed, and the black wire is used for receive audio. Here are the specific steps to follow:

1. Cut off the existing microphone plug on the Sadelta M3 microphone cord.
2. Strip about 1/4 inch of insulation from each of the four wires in the Sadelta M3 microphone cord.
3. Connect the wires to the pins on the microphone jack as follows:

• White wire to Pin 1 (Audio)
• Shield (bare wire) to Pin 2 (Ground)
• Red wire to Pin 3 (Transmit)
• Black wire to Pin 4 (Receive)

1. Solder each wire to its corresponding pin on the microphone jack. You may want to use a multimeter to verify that each connection is solid and that there are no shorts or open circuits.
2. Once you have soldered all the wires, test the microphone by speaking into it and checking that the radio's TX meter moves as you speak. Also, check that you can hear audio through the radio's speaker when receiving signals.
3. If the microphone is working correctly, use heat shrink tubing or electrical tape to cover the soldered connections and provide strain relief for the wires.

Note that some microphones, including the Sadelta M3, may have additional features such as a built-in amplifier or power supply that require additional wiring.

The power output transistor has probably failed; usual cause is poor connection, excessive SWR or widely out of specification aerial.

La radio Cobra XLR CB es un modelo m?s antiguo, por lo que es posible que no tenga un n?mero de serie. Para averiguar el a?o de producci?n, puede buscar el n?mero de modelo en el sitio web de Cobra o ponerse en contacto con su departamento de servicio al cliente para obtener m?s informaci?n. Adem?s, si planea vender la radio, es posible que desee consultar con una tienda local de electr?nica o radio CB para obtener una estimaci?n de su valor.

If you don't have the proper equipment to do the job right then don't do it.