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CB RADIO MICROPHONE AUDIO PERFORMANCE

I am in noway lashing out or picking on anyone either, I am simply stating facts that I have learned along the way through experience in my radio journeys. Im not saying everyone causes havoc but it happens everyday somewhere to someone. Not everyone runs a dirty station or signal but there are alot of them out there that really need to be corrected ;)

I'm not lashing out on anyone either. Good clean audio does make listening to the band less grating on the ears. I know that MMM,131,and Fireball/John Denver get on the air and have a little fun trying to see who can key over each other. I was just amazed when MMM started using his CP beam antenna. I got to see for myself how one works on 11 meters plus I don't think I heard his signal fade one iota.
:D
 
Think I would be far more interested in cleaning up the airwaves from dirty amps and crappy consumer electronics than from AMers/SSBers getting better usable audio from their radios. Besides, if they aren't doing it clean; then aren't thinking/doing it right through in the first place. 4-5k wide audio doesn't hurt anybody so long as they all of their 'ducks in a row'; and that can usually be heard by most as well. Try using a real-time audio scope on your radio receive (free software apps available; plug into your radio's ext spkr jack into line lever of computer sound card) to see how the filter slope isn't a brick wall after all. Even older Cobra 148's can hear up to 4k on a 2.8 filter and a Galaxy can hear up to 4.5k. YMMV.
Sorry; just can't see why all of the fuss . . .

I once posted elsewhere the RF response of a couple radios, Galaxy 959 as one. I think it rolled off about 12 dB at 10 kHz... That was the audio modulator.
 
Yep thats the 11 meters I remember..not missing anything. I am not saying his audio is not good just it's too wide for the band being used, causing interference and sad to say illegal. If someone wants to do this get a ham ticket and run 75 meters where the guys are running old broadcast xmitters which smoke any audio you will hear on 11 meters.

Had my ham tick since '88. Too many whiny appliance operators. When I lived back east a lot of ran 6-8k audio on 3885. My guess is they still do. At least on 11 I have a lot more freedom. And from what I seen there are far more people experimenting with radio on cb.
 
I have noticed that 131's audio on my equipment is a little muffled around the edges like he's pushing it too much. It's not exactly clean audio in my opinion. It's like he's got a humming sound in with his audio.

humming sound - sorry...my swamp cooler.
 
I'm still trying to figure out how he is 20 KHz wide if he is only using voice. AM bandwidth is twice the highest modulating frequency and there is no way in hell the human voice, especially a male voice is going to have any appreciable power at 10 khz. Not even if his nuts are in a vice at the time.

What's the point of hifi if you can't play a tune.
 
Had my ham tick since '88. Too many whiny appliance operators. When I lived back east a lot of ran 6-8k audio on 3885. My guess is they still do. At least on 11 I have a lot more freedom. And from what I seen there are far more people experimenting with radio on cb.

Freedom = Illegal

Of course they are experimenting on 11merers, the rigs are throw a way and you can just go use one without taking a test. You are free to do what you want but if anyone complains you are immediately wrong and have nothing to stand on.

Hey do what you want its your life.
 
Yep thats the 11 meters I remember..not missing anything. I am not saying his audio is not good just it's too wide for the band being used, causing interference and sad to say illegal. If someone wants to do this get a ham ticket and run 75 meters where the guys are running old broadcast xmitters which smoke any audio you will hear on 11 meters.

Seems there may be a few assumptions here that are not accurate. The level of skill I see being applied on 11 is increasing each year while that on the ham bands goes down. Passing the test today is no indication of knowledge since it's been so watered down.

Any idea what would happen if they started making some of the wrong multiple choice answers be the correct answers for other questions on these tests? Know how many people don't even know the questions but memorized all the answers to get an extra class?

When was the last time you got on 75 and found more than one or two AM conversations going on? Try firing up on that mode outside of a 20 KHz "window" and the slopbuckets start whining quick but they can't stay out of that AM window.

Then what do you do if you find belching in the mic all the time offensive or don't like making 20 minuet transmissions and waiting an hour to get a turn? Talk on another frequency? Not likely on the ham bands. What frequency do you use when you want to take the "dragster" out to the track for some competitive fun?

With respect to the best sound coming from antique broadcast transmitters, consider the limitations of that modulation transformer before you bet the farm on this. Today I am hearing stations on 11 with better fidelity than the boat anchors could produce. Series pass modulators and pulse width modulators easily surpass the fidelity of the best old boat anchors.

On 11 I've seen an audio generator send a tone that dropped well below the audible range and proceeded to just bounce the S meter up and down about once a second and they could reach 100 KHz. bandwidth if they didn't use brick wall filtering to control the high end cutoff. Every technology is applied from digital to a rack full of analog audio gear and every rig from a Cobra 29 to a $5000 custom built Dave Made transmitter are used.

People on 11 are more and more curious about the inner workings of their electronic equipment. Unfortunately, more and more hams become untechnical appliance operators. I'm not casting a broad net over both groups or picking sides, just pointing out some not so obvious differences. You'll still find some of the dirtiest transmitters in the world on 11 and you can still find Elmer's on the ham bands with more technical know how than most of us will obtain.
 
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I've also noticed some are quick to point out what takes place on 11 is illegal. Did we ever consider that 90% of the problem is created by these laws? Not that some aren't needed but that some have become outdated and not practical to enforce. I firmly believe 90% of inference complaints stemming from the 11 meter band could be eliminated with 3 simple rule changes and little to no effort or enforcement required. Ponder these few ideas. What would happen if Charlie allowed FM on 11 meters? What would happen if Charlie encouraged FM operation by allowing the use of linears but only in the FM mode? What would happen if Charlie allowed the ham manufacturers to enable 11 meter operation of their linears while still banning the sale of the 11 meter mono band junk flooding the market?

First, just going to FM would eliminate almost all interference problems since almost none are harmonically related after the switch to digital TV. Today's interference stems from direct RFI that is easily rectified in most consumer electronics that has a speaker or is not digital. AM, SSB or any mode that varies the amplitude is far more offensive when it comes to RFI. Most people can turn their mic gain down on AM and transmit a carrier without causing any interference. As soon as they modulate the carrier, sound comes out of everything from the PC speakers to the entertainment center. FM would fix that fast and the UK is making a big mistake allowing a shift from FM to other modes on 11.

Second, many tests have been conducted that prove RFI is not directly related or proportional to power output. Just a few watts can create virtually the same interference patterns that a thousand watts can. RFI has more to do with the vulnerabilities of consumer electronics and avoiding them than it does with transmitter power output. Encouraging those who run linears to only use them on FM would get them off of modes that bother the neighbors and would be a safer option with harmonics being less problematic today.

Third, what's the point of forcing quality amateur linear manufactures to disable 11 meter operation while the market is simultaneously flooded with tons of filthy monoband amplifiers? Blocking the flow of clean amplifiers while doing virtually nothing to curb the tide of filthy ones seems counter productive. Anyone with a computer can buy just about any low end amp they want but none of the clean ones will work out of the box. I seriously doubt it would encourage many more people to start using linears on 11. It would just give those who do an option to have a much cleaner signal and decrease demand for the junk clogging the band up.
 
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How effective - if at all - would using a bandpass filter be (6th order) on curbing spurious signals adjacent to the 11m band using an average cheap amp?

It would be very effective at attenuating the harmonics that land on the top end of the 6 meter band or extend into VHF high band but would be completely ineffective at reducing things like direct RFI, IMD or adjacent channel interference within the band. The reason being is these last 3 problems relate to signal content that would still be within the bandwidth of the filter.
 
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I've also noticed some are quick to point out what takes place on 11 is illegal. Did we ever consider that 90% of the problem is created by these laws? Not that some aren't needed but that some have become outdated and not practical to enforce. I firmly believe 90% of inference complaints stemming from the 11 meter band could be eliminated with 3 simple rule changes and little to no effort or enforcement required. Ponder these few ideas. What would happen if Charlie allowed FM on 11 meters? What would happen if Charlie encouraged FM operation by allowing the use of linears but only in the FM mode? What would happen if Charlie allowed the ham manufacturers to enable 11 meter operation of their linears while still banning the sale of the 11 meter mono band junk flooding the market?

First, just going to FM would eliminate almost all interference problems since almost none are harmonically related after the switch to digital TV. Today's interference stems from direct RFI that is easily rectified in most consumer electronics that has a speaker or is not digital. AM, SSB or any mode that varies the amplitude is far more offensive when it comes to RFI. Most people can turn their mic gain down on AM and transmit a carrier without causing any interference. As soon as they modulate the carrier, sound comes out of everything from the PC speakers to the entertainment center. FM would fix that fast and the UK is making a big mistake allowing a shift from FM to other modes on 11.

Second, many tests have been conducted that prove RFI is not directly related or proportional to power output. Just a few watts can create virtually the same interference patterns that a thousand watts can. RFI has more to do with the vulnerabilities of consumer electronics and avoiding them than it does with transmitter power output. Encouraging those who run linears to only use them on FM would get them off of modes that bother the neighbors and would be a safer option with harmonics being less problematic today.

Third, what's the point of forcing quality amateur linear manufactures to disable 11 meter operation while the market is simultaneously flooded with tons of filthy monoband amplifiers? Blocking the flow of clean amplifiers while doing virtually nothing to curb the tide of filthy ones seems counter productive. Anyone with a computer can buy just about any low end amp they want but none of the clean ones will work out of the box. I seriously doubt it would encourage many more people to start using linears on 11. It would just give those who do an option to have a much cleaner signal and decrease demand for the junk clogging the band up.
Shockwave I respect everything you're saying here but I am sorry but please explain why amps should be legal on 11 meters? I agree with the dirty amps that have flooded he market and those are causing htons of interference and hey need to be eliminated. As I said above cb should be FM but not on 27mhz but on UHF.

If you want to run power and talk DX legally then become a ham. No offence to you but I find all this whining about how the laws are wrong a bit like saying I can't do what I want so change the rules. I agree that the FCC screwed up and continuing to do so and because of funding is ineffective.

Anyway this thread is way off topic now :oops:
 
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