The gain is the highest with no signal and it's amplifying its own noise.

As Mister Hat said with no incoming signal the AGC circuit is going to have all the stages turned up to maximum. Once a signal is received the gain of the stages is lowered. The higher the incoming signal the less gain there is. Also the volume was turned up really high at several points in this video, up the whole way in some parts.

@@mikesradiorepair there are scientists that say that you actually hear the big bang and the residual noise from that moment.

I despise radios with a noisy receiver alignment. Thank your for your answer.

Yes, it's called the CMB or CMBR for cosmic microwave background radiation. Was discovered by Penzias and Wilson of Bell labs in the mid 1960's.

Yep, any spark-noise from the spark plug is contained (shielded) by the cylinder head and engine block. The distributor cap is where most of the impulse noise escapes. Resistor wires limit the current flowing between the gap of the rotor button and the distributor cap electrodes.

CB operators like ANL? Figures.

Just add @gmail.com to my UKposts user ID to email me.

Honestly I have never heard of automotive LED lights causing noise in a radio. The noise is usually with 120V AC house lights. They use a switch mode power supply which is very noisy. I suspect your light's may have a buck converter to reduce the voltage or more correctly a constant current supply to the LED's. Only a guess however since I have never run into this myself. Two things I would suggest. Make sure the radio is grounded, not the power cord ground but make sure the radio chassis/cabinet is grounded. Second you might try a DC power cord inline filter. I suspect the noise may be getting into the radio through the power wires. Powerwerx makes a nice heavy duty power line filter. powerwerx.com/dc-line-noise-filter-oemt

When in doubt go with the higher voltage.

ukposts.info/have/v-deo/f3JejKutqKtomXU.html Correction to the schematic. Pin 7 needs to be attached to ground.

The best coax for any application is the best you can afford. The higher the quality of the coax the more it cost. You can get crazy and spend thousands of dollars on large diameter premium hard line or use something more reasonable like LMR240 or LMR400.

Probably not the type of ignition noise you are thinking about. You probably don't have spark plug wires. Most vehicles these days have coil on plug packs, there is no spark plug wire in most cases. There is however a bunch of other electronics in modern vehicles that cause interference on HF. Proper grounding, connection directly to the battery and judicious application of ferrite cores/beads to power and coax cables can greatly attenuate this interference.

@@mikesradiorepair Thanks for the reply. I do have the power grounded to the battery terminal. Someone suggested that I should move it off the terminal to the chassis ground.

Honestly I'm not the right person to ask about that. I don't sell radios, I only do repairs. The best people to ask about something like that would be a shop that sells radios. They are going to have a better idea of what is currently available that would meet your requirements.

In your opinion is there a particular radio that can handle the shock and vibrations of being in a dump truck?

Any modern radio that uses surface mount components is going to be more resistant to damage from shock and vibration. One of the biggest problems in high vibration environments is bad solder joints. Older through hole design boards are more susceptible to solder joint failure because the parts are hanging off the board by their wire leads. Surface mount parts have no wire leads, they are soldered directly to the surface of the circuit board.

As I said before the best cable is the best you can afford. In general the more it cost the higher the quality .

Just add @gmail.com to my youtube user ID.

Honestly I'm not sure. I'll make a quickie video later this evening showing how to build one. Might not get uploaded until tomorrow.

That would be great Mike!

I’m working in Gettysburg PA until tomorrow then I’m driving back home to Indiana for surgery Tuesday. I can spend some recovery time with a bread board Wednesday. I assume that the heart of the device is a 555?

@@mikesradiorepair That is something I don't have for my bench, that would be awesome

Buy a new radio.

Royce was a good manufacturer. They did things a little different than many other manufacturers. The 604 is a good example. It has what I would call a "one chip wonder". Most of the receive circuit to include RF Amps, mixers and IF stages are all done on a single IC.

@@mikesradiorepair Thank you so much!

@@mikesradiorepair Hi , I have a Whistler 900 that was working and quit a few months ago . Sent it to a local cb guy and it is now dead ! Just lights up ! No audio and no transmit ! I dont know what he did but he offered me another radio for free because it quit while he had it ! Fair enough , but I miss my neat Whistler 900 ! Could you have a look at it ?

No, it needs to have a very fast rise time and be a very short duration pulse. I'll make another video this evening with a schematic and demonstration of the circuit. Might be tomorrow until it gets uploaded.

@@mikesradiorepair Thank you very much sir and have a great evening.

@@mikesradiorepair Awesome video. Looking forward to the schematic.

No, it works on fast rise time pulses. It will still blank the sound if a pulse triggers the circuit while someone is talking but you will never hear it. The amount of time the audio is "blanked" or muted is so short our brain can not hear it. Same effect as a flashing light. Flash a light fast enough and we can not tell it's flashing, it looks like a light that is on continuously but it can be turning on and off 30 or less times a second. Our brains are VERY slow.

@@mikesradiorepair thanxx man !

If it's a modern car join the party. All the noise from the vehicle computers is horrible in some of my newer vehicles. I installed a Powerwerx line filter in those vehicles and it pretty much eliminated it. powerwerx.com/dc-line-noise-filter-powerpole-connectors

Are you sure it's engine noise? In modern vehicles it's not engine noise but electronic noise generated by the vehicles electronic systems that create a lot of the noise. If the noise doesn't change with engine speed then it's not engine noise. I have a fairly new car here that it took me a good bit of fiddling with to finally get rid of all of the electronic noise generated by vehicle computer systems.

@@mikesradiorepair Thanks for the reply. It's an 88 pickup with older internals. I swapped out all of the "newer" in favor of an older setup with carb and HEI distributor. It does change with engine RPM, the high pitch whine gets louder as I hit the accelerator. When I'm driving it's almost impossible to hear above it. At idle, it's still annoying, but bearable.

Make sure everything has a good ground. You can also try sticking a filter on the power cord. These help in some applications.

@@mikesradiorepair I have everything grounded with star washers a plenty, but I'll double check everything. Do you have a filter you'd recommend?

@@jizomeovonsteelwind powerwerx.com/dc-line-noise-filter-oemt?gclid=EAIaIQobChMIy8W_9ZbG4AIVwSNpCh0M1QJ_EAQYBSABEgJ7-vD_BwE