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To swing or not to swing

Discussion in 'CB and Export Equipment and Accessories' started by ron103067, Apr 12, 2010.

  1. ron103067

    ron103067 Active Member

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    I know this will probably get alot of tempers rising but not wanting to. I want honest opinions on swing. What is good and bad. I have a radio that I got used and it is setup with a 2 watt dk and a swing to 20 watts. Now this radio from the reports sounds decent but does this radio overdrive my amp and is this natural I thought there was supposed to a limit to what is good for the radio and amp any help would be appreciated


     
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  2. good topic ron ;)

    our modulated signals on both am and ssb require swing to modulate the signal . so swing is a must have thing . the proportion of deadkey to swing is important and deadkeying %25 of what your amp/radio will cleanly swing is suposed to be optimal for AM transmissions . and of course SSB has no deadkey and is all swing .

    adding a amp can change things though particularly since cb amps arent linear in operation and dont amplify our signals in the same proportion that is put into them . typically they require something more along the lines of %10 deadkey in to get a %25 deadkeyoutput out of them . sometimes playing with the input level on the amps pot or switch can get us closer to something closer to linear input and output , but im sure the success of that will vary from one amp type to another .

    im looking forward to the replies on this one ;)
     
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  3. JoeDirt

    JoeDirt Active Member

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    Now matter what your not going to get over a 100% modulation with any swing kit! Just because your scope shows its more than a 100% with a swing kit does not mean its true.

    It all depends on the radio and how its setup! You can get good clean audio out of a properly setup swing kit! Most swing kit you need to upgrade to better components to handle the extra current that the transistors are drawing. Some radios your not getting nothing but distortion when you install a swing kit.

    If your over driving your amp it starts to change things, If your radio dead keys 2 watts and swings 10 you want you amp to dead key 200 and swing a 1000 or 20 watts swinging a 100. You want the same percentage of modulation out of your radio and your amp. Transistor amps will start to clip when they reach there peak output, so if your over driving your amp most likely it will clip some of your audio!

    What radio and amp are you running?

    In my opinion if you want more watts/drive and run your equipment to its full potential add a swing kit. It will take some more time to setup RIGHT! I doubt your going to hurt the radio but if your over driving the amp out of spec that can be damaging!
     
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  4. Robb

    Robb Yup

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    Let's keep in mind that MOSFET's will key at 1 watt and swing up to 30 watts. They can do what bipolar transistors cannot do in this regard. Is it bad that they behave this way? Do they sound bad? No; they do it all day long and get the job done well. You cannot expect for MOSFETS to be held to the same rules and standards as bipolar transistors because they are built differently and their electrical characteristics are different.

    Aren't new things scary?!?
    LOL!
     
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  5. here we go :)
    [​IMG]
     
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  6. Highlander_821

    Highlander_821 Amour d'Ecosse

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    I strongly disagree.

    Just because a mosfet CAN do this, does not mean that it sounds good. Robb and his locals appear to think that they sound good this way. I think they sound terrible, raspy, crunchy, badly overmodulated.

    A radio that uses mosfets can be tuned to just swing at a 1:4 ratio. That is how they should be set up. Anything more not only sounds crappy, but it trashes the band, making it harder for others to use.

    I'm not saying that they aren't "loud", I'm am saying that they sound bad.
     
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  7. slprydk

    slprydk Member

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    I have been a tech for over 30 years, this statement is just not true...

    The only way to check the % of modulation after installing a swing kit is with a scope simply because you can't calibrate a modulation meter with your RF power fluctuating all over the place.
     
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  8. slprydk

    slprydk Member

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    I am with you on this, part of the problem is "loud" has become the way of saying you sound good regardless of the quality of the transmission. Also I think most wannabe techs or "Google Techs" look at the peak watts on a dosy as the gospel truth. A cheap peak reading meter like that has a tendency (or it seems) to add in the harmonics as power, that is why when people mess with the TVI traps in the output stages (spread them coils...) it looks like they have more power but your radio is only putting out more harmonics, the end result is a poorly tuned radio with the maximum harmonic output (splatter, noise, distortion).

    I use a scope and a RMS type meter to tune a radio myself but that isn't practical for everybody. If you have to use a peak reading meter try adding a low pass filter between the radio and the meter before you tune, and always tune the radio on a dummy load not your antenna (and don't mess with the TVI coils).

    Jim
     
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  9. JoeDirt

    JoeDirt Active Member

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    If you set your swingkit up for asymmetrical modulation your carrier increases with your mod, so your never going to really get over a 100% CLEAN MOD. You can always run more than a %100 but you negatives are going to be at zero volts creating distortion.

    And yes mod meter suck at telling your the correct % of mod, but on a scope when your looking at a radio with a swingkit the carrier increases with the modulation so your scope lies to you too. The only way to show what you modulation is really doing with a swing kit you need a demodulator in conjunction with your scope.
     
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  10. Robb

    Robb Yup

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    Funny; I never ask others when talking skip some 9,000 miles away in New Zealand how my radio sound. Yet they always give me flowers w/o asking. Happens all of the time. They don't know about these dumb arguments and bickering, they just hear me and I hear them. Simple.

    Oh; are you referring to that video with the mic I reviewed? The guy who shot that video had his radio up too high. I thought you knew that already? I use my OmegaForce every day and wouldn't trade it for another.
    Sounds Fantastic!
    :D:D:D
     
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  11. Moleculo

    Moleculo Administrator Staff Member

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    I don't like the way a radio sounds that has a huge carrier to peak ratio, either. It's loud as hell, but it doesn't sound good to me. I realize that a lot of people like it, though.

    Robb, I assume that your New Zealand example was using SSB, not AM? The carrier/peak ration discussion is moot on SSB, although over modulation is still an issue.
     
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  12. Moleculo

    Moleculo Administrator Staff Member

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    Not exactly, and we've been through this before. Study some of the material here for a more detailed discussion:

    Oscilloscope Monitoring | eSSB | SSB | AM Audio Modulation, Amplifier and System Linearity
     
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  13. Robb

    Robb Yup

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    Yes - SSB...
    Not an issue with anybody that I talk to regardless if they are ten miles away or several thousand.
    Never has been either.
    It's just a rehash of the same old jive.
     
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  14. 15minigrass

    15minigrass Active Member

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    O.K. Here╩╗s a gate of me on 43WR137 photobucket video log. Right around the 50 sec. mark. Im running a President Grant w/NPC-RC (diode-resistor)mod, running stock microphone, and my Black Widow 350 @ 240+ watts.

    Radio DK is 2+ watts swinging 22+ pep. I think it sounds kinda muffled due to the stock mic Im using. If it was maybe a power mic(D104/575/Road Devil) then it might have sounded different.
    15 minigrass Jim AM video by 137dan - Photobucket

    Heres 1 with the same setup (mic/radio/amp) but on SSB!!! it right around the 21:18 mark.
    Justin.tv - CA. USA - Recorded live Apr 11 2010 at 8:19PM GMT

    I will try to get a different gate when I get my turner +3 mobile mic and see if it makes a difference in audio etc.

    Aloha, Jim.
     
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  15. Highlander_821

    Highlander_821 Amour d'Ecosse

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    Sorry, but the guy's volume on his radio had NOTHING to do with your crappy sounding radio.

    And the fact that you get "flowers" all the time only means that there are lots of other people out there that are just as ignorant as you.

    Once again, I am not saying that 1 watt swinging 30 isn't "loud." I am saying that it sounds like crap. I am overjoyed to know that you use your radio everyday and love it. Doesn't change the fact that it sounds like crap.
     
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