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Post by wrench78 on May 11, 2017 9:04:48 GMT -5
Doing my research I found some radio's have a FM, AM, USB, LSB settings. Is the FM setting like the FM radio stations on my car radio or is it a talking frequency? Not familiar with FM band on CB radios.
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Post by SIX-SHOOTER on May 11, 2017 12:42:51 GMT -5
FM has no forward swing.It's all carrier & it is like FM on a 2 meter or 440 VHF or UHF radio.I don't like it & don't know anybody who uses it in the USA.It's popular in Europe I understand but not so in the USA for CB Radio usage anyway.Just like any other mode you will still be on the same frequency no matter what mode you choose.
Six-Shooter
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FM mode???
May 11, 2017 15:57:54 GMT -5
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Post by MonkeyMan on May 11, 2017 15:57:54 GMT -5
I've had my FM equppied Galaxy Pluto for 25 years and I could count on one hand the number of times I've carried on a conversation in FM mode. Wouldn't even need the whole hand.
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Sandbagger
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Post by Sandbagger on May 11, 2017 18:19:06 GMT -5
Doing my research I found some radio's have a FM, AM, USB, LSB settings. Is the FM setting like the FM radio stations on my car radio or is it a talking frequency? Not familiar with FM band on CB radios. FM is a MODE, like AM and USB, LSB. It's a different method of modulating your signal. It's not legal to use in the US on CB radio. But many of us have tried it at some point or another. Personally, I like the mode. Everyone's (or ALMOST everyone....) audio is crisp and crystal clear, and if you weren't watching the S meter, you couldn't tell the difference between someone giving you S7, and someone giving you +20db over S9, as the volume is pretty constant. The downside is that weak signals get lost in a much higher internal noise level, and are much harder to copy than on AM. A great mode if you're talking to locals with relatively strong signals.
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Sandbagger
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Post by Sandbagger on May 11, 2017 18:22:05 GMT -5
I've had my FM equppied Galaxy Pluto for 25 years and I could count on one hand the number of times I've carried on a conversation in FM mode. Wouldn't even need the whole hand. Back in the mid 80's, I was part of a group who hung out on 26.675 FM. It was during a high skip period, and it was great for getting away from the AM hash and trash.
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FM mode???
May 11, 2017 20:45:38 GMT -5
via mobile
Post by MonkeyMan on May 11, 2017 20:45:38 GMT -5
I've had my FM equppied Galaxy Pluto for 25 years and I could count on one hand the number of times I've carried on a conversation in FM mode. Wouldn't even need the whole hand. Back in the mid 80's, I was part of a group who hung out on 26.675 FM. It was during a high skip period, and it was great for getting away from the AM hash and trash. Now, there's a good use for it.
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Post by wrench78 on May 11, 2017 22:04:01 GMT -5
Great info everyone. Thanks for all the help
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Post by BBB on May 15, 2017 10:14:20 GMT -5
Wonder if it would stir up the OO's if they found a bunch of us operating in FM mode on 11 meters.
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Post by Sandbagger on May 15, 2017 10:49:58 GMT -5
Wonder if it would stir up the OO's if they found a bunch of us operating in FM mode on 11 meters. It would certainly be obvious.
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Post by ytradio on May 17, 2017 8:07:18 GMT -5
And they would certainly be stirred up, " OH BOY, something we can whine about!!!"
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Post by cbrown on May 19, 2017 12:49:51 GMT -5
Back in the mid 80's, I was part of a group who hung out on 26.675 FM. It was during a high skip period, and it was great for getting away from the AM hash and trash. We had a DX group that did that, but we used 27.675 Mhz for our FM channel. It actually worked well, and anyone with a Class C amp could boost their signal strength.
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Sandbagger
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Post by Sandbagger on May 20, 2017 16:50:54 GMT -5
Back in the mid 80's, I was part of a group who hung out on 26.675 FM. It was during a high skip period, and it was great for getting away from the AM hash and trash. We had a DX group that did that, but we used 27.675 Mhz for our FM channel. It actually worked well, and anyone with a Class C amp could boost their signal strength. Class "C" amps work very well on FM..
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Post by wrench78 on May 20, 2017 22:28:48 GMT -5
We had a DX group that did that, but we used 27.675 Mhz for our FM channel. It actually worked well, and anyone with a Class C amp could boost their signal strength. Class "C" amps work very well on FM.. There we go again. Speaking another language. LOL. What is a Class C amp.
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Post by Sandbagger on May 21, 2017 6:22:54 GMT -5
Class "C" amps work very well on FM.. There we go again. Speaking another language. LOL. What is a Class C amp. One that lacks the proper bias to work well on AM and SSB. (aren't you glad you asked! )
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Post by thehobo on May 21, 2017 11:49:32 GMT -5
oh wow, way back?, in the earley days that fm was put on the options heck i dont even remember what radios we all had?? it was fun to get on ch. 11, old 23 chs, and give the locals a fit trying to get to us.. lol.. now that was fun.. however we stayed off of ch 16 as that was the ssb channel.. and yes with a 100 watt amp one could go far, like overseas, mostley around great britan germony and the slav countries.. not often but every once in awhile.. oh well days gone by, althou a buddy of mine once in awhile do get on fm on 269150.. being as skip hasnt been good latley we fool around alot on different modes.. ok, my nickles worth..
thehobo
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Post by Sandbagger on May 21, 2017 14:24:55 GMT -5
oh wow, way back?, in the earley days that fm was put on the options heck i dont even remember what radios we all had?? it was fun to get on ch. 11, old 23 chs, and give the locals a fit trying to get to us.. lol.. now that was fun.. however we stayed off of ch 16 as that was the ssb channel.. and yes with a 100 watt amp one could go far, like overseas, mostley around great britan germony and the slav countries.. not often but every once in awhile.. oh well days gone by, althou a buddy of mine once in awhile do get on fm on 269150.. being as skip hasnt been good latley we fool around alot on different modes.. ok, my nickles worth.. thehobo A lot of people mistaken FM operation with being "off-frequency". Since you can slope detect FM on an AM rig with a variable receiver or clarifier, and people would hear it clearly 1.5 or 2 khz off of center frequency, they assumed that the FM station was simply transmitting on AM but 2 Khz off. But AM always sounds like a ripped speaker on FM, so not very compatible.
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Post by BBB on May 23, 2017 7:37:15 GMT -5
Class C amps are used by CB'ers because they are more efficient (yet more distorted). You get more RF output power from a (2) pill 2879 Class C amp than a similar amp biased Class AB. Personally I can't tell the difference on AM mode. Class C amps should not be used for SSB mode due to the increased distortion that is definitely audible. Just last night around 8:30 PM on CH 13, 27.115 MHz, there were some fellows testing their radios in Southern Florida. They were on USB and I contacted them with 10 watts. Then they switched to FM mode. I was able to converse very well with them, squelch engaged and all, with only 40 watts. My first FM DX
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Post by Sandbagger on May 23, 2017 7:49:59 GMT -5
Class C amps are used by CB'ers because they are more efficient (yet more distorted). You get more RF output power from a (2) pill 2879 Class C amp than a similar amp biased Class AB. Personally I can't tell the difference on AM mode. Class C amps should not be used for SSB mode due to the increased distortion that is definitely audible. Just last night around 8:30 PM on CH 13, 27.115 MHz, there were some fellows testing their radios in Southern Florida. They were on USB and I contacted them with 10 watts. Then they switched to FM mode. I was able to converse very well with them, squelch engaged and all, with only 40 watts. My first FM DX Class "C" amps are used by CB'ers because most don't know any better. They buy what is offered, and many also buy into "all knobs to the right" hype that amp makers often peddle. There was NO difference in PEP output when I added bias to my Dave Made 2 (and 4) pill. But it now sounds far better on SSB, and the level of splatter on AM decreased as well. Yea, if you drive them sufficiently (but not too much), a class C amp might "sound" acceptable to the ear on AM, but the scope and the spec-an will show the distortions.
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Post by cbrown on May 26, 2017 13:04:53 GMT -5
Leave Class C amps to the FM & CW signals they can handle.
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Post by American Eagle 813 on Jul 2, 2017 22:42:13 GMT -5
I have a few radios capable of FM. I think in over 23 years on the radio I have had one conversation on FM.
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Post by thejerk on Jul 7, 2017 8:28:16 GMT -5
Class C amps are only bad when over-driven, which is all the time since bigger is badder...I ran a Fat Boy 1x4 (all 2879s) on SSB all the time and never once had someone complain...but I was keeping inside the capabilities of those transitors, which was actually harder to do that it sounds. I still have a TS350HDV on the shelf that is class C, and it did good on SSB as well.
I've owned several FM-capable radios over the years, never even turn one to FM because (unless you know one of your buddies will be there), there was no sense in it (nobody home).
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Post by Sandbagger on Jul 7, 2017 16:42:03 GMT -5
Class C amps are only bad when over-driven, which is all the time since bigger is badder...I ran a Fat Boy 1x4 (all 2879s) on SSB all the time and never once had someone complain...but I was keeping inside the capabilities of those transitors, which was actually harder to do that it sounds. I still have a TS350HDV on the shelf that is class C, and it did good on SSB as well. I've owned several FM-capable radios over the years, never even turn one to FM because (unless you know one of your buddies will be there), there was no sense in it (nobody home). Class C amps should never be used for any amplitude modulated signal. There will ALWAYS be distortion when the signal modulation reaches and falls below cutoff, which causes a sharp flatline at the zero power level (which causes splatter), rather than a smooth sinewave. It's less noticeable on AM, where you can run the amp with the right drive level and it can "sound" acceptable to the ear, in much the same way as a clipped modulation limiter can sound "ok" to the ear, even if it is generating splatter. On SSB, the distortion is much more noticeable. I have yet to hear a class "C" amp not sound "rough around the edges" on SSB. Understandable, yes, but not crystal clear sounding. Some people may feel that this is acceptable. I'm a stickler for good quality audio, and any sort of distortion is a no-go for me. Since adding the necessary bias to make the amp class AB is not all that tough to do, that's what I've done to my amps that were originally class C. They're clean as a whistle on SSB now. And most Texas Star amps (with the exception of the one pill "modulator"), are class AB, and work great on SSB.
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Post by thejerk on Jul 8, 2017 7:32:58 GMT -5
Class C amps are only bad when over-driven, which is all the time since bigger is badder...I ran a Fat Boy 1x4 (all 2879s) on SSB all the time and never once had someone complain...but I was keeping inside the capabilities of those transitors, which was actually harder to do that it sounds. I still have a TS350HDV on the shelf that is class C, and it did good on SSB as well. I've owned several FM-capable radios over the years, never even turn one to FM because (unless you know one of your buddies will be there), there was no sense in it (nobody home). Class C amps should never be used for any amplitude modulated signal. There will ALWAYS be distortion when the signal modulation reaches and falls below cutoff, which causes a sharp flatline at the zero power level (which causes splatter), rather than a smooth sinewave. It's less noticeable on AM, where you can run the amp with the right drive level and it can "sound" acceptable to the ear, in much the same way as a clipped modulation limiter can sound "ok" to the ear, even if it is generating splatter. On SSB, the distortion is much more noticeable. I have yet to hear a class "C" amp not sound "rough around the edges" on SSB. Understandable, yes, but not crystal clear sounding. Some people may feel that this is acceptable. I'm a stickler for good quality audio, and any sort of distortion is a no-go for me. Since adding the necessary bias to make the amp class AB is not all that tough to do, that's what I've done to my amps that were originally class C. They're clean as a whistle on SSB now. And most Texas Star amps (with the exception of the one pill "modulator"), are class AB, and work great on SSB. A TS that's been gutted and rebuilt...they don't always have the same biasing they left factory with... Let be real for a minute... So you're telling me that you can tell everytime someone talks SSB with a class C when skip is happening? You have better hearing than I, considering most transmissions are already questionable at best, and not even close to high definition. Looking at it on a scope is one thing, hearing it when talking hundreds or thousands of miles away in less than ideal conditions is another. I was suckered into that AB/C discussion back in the day, was buying nothing but AB amps because of it. Point is that with the majority of the available equipment on the market, the guy listening won't know if that's a AB, C, or barefoot radio. And again, most issues arise when the radio is clipped (garbage in/garbage out) or the amplifiers are overdriven. That five pill I had didn't even splatter onto adjoining channels because the radio was set up correctly and I wasn't trying to wring every last watt out of the system. That was a DX959, 1x4 Fat Boy, RG8, and a well-mounted, 102-inch whip. Don't get me wrong, I don't disagree that AB is better; but in the real world we are hard pressed to notice it in the CB application.
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Post by Sandbagger on Jul 8, 2017 14:15:52 GMT -5
Class C amps should never be used for any amplitude modulated signal. There will ALWAYS be distortion when the signal modulation reaches and falls below cutoff, which causes a sharp flatline at the zero power level (which causes splatter), rather than a smooth sinewave. It's less noticeable on AM, where you can run the amp with the right drive level and it can "sound" acceptable to the ear, in much the same way as a clipped modulation limiter can sound "ok" to the ear, even if it is generating splatter. On SSB, the distortion is much more noticeable. I have yet to hear a class "C" amp not sound "rough around the edges" on SSB. Understandable, yes, but not crystal clear sounding. Some people may feel that this is acceptable. I'm a stickler for good quality audio, and any sort of distortion is a no-go for me. Since adding the necessary bias to make the amp class AB is not all that tough to do, that's what I've done to my amps that were originally class C. They're clean as a whistle on SSB now. And most Texas Star amps (with the exception of the one pill "modulator"), are class AB, and work great on SSB. A TS that's been gutted and rebuilt...they don't always have the same biasing they left factory with... Let be real for a minute... So you're telling me that you can tell everytime someone talks SSB with a class C when skip is happening? You have better hearing than I, considering most transmissions are already questionable at best, and not even close to high definition. Looking at it on a scope is one thing, hearing it when talking hundreds or thousands of miles away in less than ideal conditions is another. I was suckered into that AB/C discussion back in the day, was buying nothing but AB amps because of it. Point is that with the majority of the available equipment on the market, the guy listening won't know if that's a AB, C, or barefoot radio. And again, most issues arise when the radio is clipped (garbage in/garbage out) or the amplifiers are overdriven. That five pill I had didn't even splatter onto adjoining channels because the radio was set up correctly and I wasn't trying to wring every last watt out of the system. That was a DX959, 1x4 Fat Boy, RG8, and a well-mounted, 102-inch whip. Don't get me wrong, I don't disagree that AB is better; but in the real world we are hard pressed to notice it in the CB application. Since we're being real here, most skip stations wouldn't tell another one if they sounded crappy anyway (that would be rude, don'tcha know), as long as they can be understood. With few exceptions, the majority of skip stations I hear are of the "all knobs to the right" mentality and tend to splatter 5 or 6 channels (or more) in either direction, and some are actually proud of that fact. I guess they see it as a badge of power and prestige. And yes, I can tell instantly if a station is running a class C amp (or they tweaked the bias of their radio improperly)on SSB. It's as plain as the noise on your face. Their audio will sound raspy or rough around the edges, and more noticeable during the quieter periods between voice peaks. Granted, there may be ADDITIONAL reasons why they sound fuzzy, but running a class C amp on SSB will guarantee it. If I had the time, I'd make a recording of the difference, and once you hear it, you'll recognize it when you hear it again on the air. Maybe I'll see about it Sunday night if our 10 meter net is dead. I know a lot of the garage shop competition amp builders poo-poo the need for class AB biasing and will tell you that you don't need it, or that their amp will put out more without it (gotta hit those big watt numbers after all). But it's really more about them not wanting to go to the extra trouble of setting them up properly for AB bias. It's not worth the effort for them (more time + xtra parts = less profit). Especially since their primary customers are already running hacked up radios. The extra distortion of the class C box won't add much more to their already distorted radio signal. And you're right, a class C amp driven by a properly set-up radio, will be far less dirty than a class C amp overdriven by a peaked and clipped splatterbox radio. But it's all a matter of degree. I like my station to sound like I'm running barefoot, even when I'm not. The audio sound quality doesn't change when the switch is flipped. Clean signal in to a class AB box = clean signal out. Clean signal into a class C box = cutoff power distortions and minor splatter. Dirty signal into either class box = dirty signal out.
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