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Please explain

M

MatchboxMan

Member
Apr 2, 2006
14
0
11
U.S.A.
So like I've explained in other posts I've been out of the cb loop since the early 70s.
I read in here people are cutting back the power to about 1 watt on a dead key to generate more talk power in the sidebands I believe, but if you have 100% modulation before you do this won't you exceed 100% and cause splatter, adjacent channel interference and creat tvi?
Why not DSSC? double sideband supressed carrier.
Or am I missing something?
 

I have never seen that here on the forum. What you do see alot of is when running a small amplifier the dead key has to be tuned back to 1-2 watts from the radio to properly run the amp. SSB has no carrier anyway so I don't see how that would even be affected.
 
Well maybe I'm over analyzing the thing, but it seems to me that a properly designed amp for a cb rig should accept 4 to 12 watts input pwr. of course I'm going by the old days. :)
But this ol' dawg can learn new tricks, which is why I ask. (hope no one minds :D )
 
IM more confused then normal here ? 1 watt on SSB ? Huh ? if audio has to do with SSB how much audio would one have then with 1 watt on SSB ? or am I totally missing something here ? if so ,what is it then ? My Cobra XL 450 according to doc's will key at 1/10 of a watt on SSB .....OK ....II must be missing something here ? hmmmm
 
What you are talking about is called "Swing". It comes from the movement of the power meter needle. Now, what you need is for someone to explain why swing is good, bad, necessary, essential, foolish, or dumb. Liable to get a lot of opinions.

Rich
 
1 watt dead key = over modulation!
If you have say a 50 watt export you divide your peak power by 4 and that's what you set your key at. 50 / 4 = 12.5.
Someone on another forum said it was peak power divided by 2 but i dont set mine that way. But if it is 2 then that would mean that i should have my dead key on my 95T set at 95 watts with a peak reading of 190(190 / 2 = 95). There is no way in hell i would every run a key that high,i set mine at 47 and all on air reports or very good.
 
i understand what you guys are saying ,I just didn't understand what matchbox man was saying or asking ? ,I think IM even more confused now then from my last post )-:
 
AM is 2 sidebands WITH a carrier.

And to answer the question, "if you have 100% modulation before you do this, won't you exceed 100% and cause splatter, adjacent channel interference and creat tvi?" As Justin already pointed out, YES!

Now I say, "Welcome to CB radio!" Where ducks are LOUD and signals are dirty! :twisted:
 
Big swing on am is for people that don't understand how am is suppose to work, and the only thing they accomplish is creating a splatter box that bleeds 200 khz each side of where they are trying to talk. What I have never understood is why the cb crowd is so fascinated with watching a meter needle swarp back and forth, if that is all you want why not use ssb then all your output is used to swing the needle.
 
No offence Match Box , for me ,it might just have been the way you worded your question ? ....It's not always easily understood by me , When radio's like Magnums and other have switches on them that will bring the carriers down to 1 or 2 watts and swing 50 ? and guys swear up down what a wonderful thing it is and how much they love there radios. I personally don't care how a guy runs his radio as long as I can understand what he's saying to me in the first place ,(if there talking to me to begin with) IM not a CB Cop or FCC or a tech that finds the need to frown over this and that when it is CB radio related , I do understand TVI / Bleed over , if they feel that it is there need to be concerned about these kinds of things,so be it. When you say 4 to 12 watts input power from cb's into amps ,those numbers seem rather high ? but then again ,it's possible I might be just misunderstanding you again ? ........I'd like to know what Amp builders are using when they go to test there amps and then come up with the numbers that they decide to put on the front of there boxes ? Because I truely doubt you would even see close to those numbers if they were tested with a "quote on quote" properley tuned radio !! Take a 2 x 2879 box ......do you really think that you would see 350 watts pep out of it if it was tested and benched with a 2 watt DK swinging 8 watts pep at 100% modulation ? I truly doubt it )-: I think you might see 250 if you were lucky , those transistors are only rated at 120 watts a piece ,figure the math here , but there's a real good chance that you would see 350 with a radio doing 2 to 20 watts pep with the audio off the scale (-: ....but ,you would then get to shake hands with TVI/Bleed over and loss of power one way or the other according to the sources at hand. So what would be the better way to go here and hopefully not have the loss in the first place ? I think I might have already answered that one . My personal radio does 2 and swings 25 watts pep (me bad boy) into a 4 x 454 box , I see a 120 DK to 450 pep swing on the high side , I put a 2 to 8 watt pep swing radio at 100% modulation ,I see the same 120 DK but now I only see about a 300 watt pep swing ......I suppose that is closer to the 4 x 80 that the transistors are truly putting out which would be 320 ???? Hmmmmm but what happens to the 4 to 1 ratio ? It's no damned wonder I've just been a cb radio bozo all these cotten pick'in years !! But after reading and learning a little bit about this and that from those that apparently know whats really going on with all this stuff , it doesn't seem to change a whole lot of cb radio operators out there that seem to like what they like even though they tend to get the shaft from others for doing so , like I said , if your stuff works for you and your personally happy with it , so be it . ...but heres one for you , if one knew they could get out further and be heard clearer when all was tuned up according to the machines , wouldn't one rather go that route ? , in other words ,that would mean ,forget about the swing thing and the numbers on the front of the amp boxes (Lord knows who made them in the first place?) cause if your swinging like you think you are ? chances are it's all about waste of power )-: so by the time you got it right ,you would be seeing those lower numbers I already talked about but it would supposedley be a more honest and less waste of power ,question would be , would you be gaining or losing here minus the TVI/Bleedover ? .....in other words , should you get more for less ? (-:
 
The long and short of it is

many CBers are mesmerized by their power meters...

Picture Homer Simpson drooling over a pitcher of beer.

Mmmmm...watts :p

Look at the 2SC2290 transistor, which is spec'd for a max input drive of 4W PEP. Even with 4 of them, that would be 16W PEP...so a neat trick is to turn down the carrier via some sort of swing kit, peak the input drive to around 20-25W peak from a 1W carrier, and you can get away with a much higher peak output without blowing up the transistors, for a while anyway.
 
re: My questions

No offense taken Switchkit, I guess as I get older I don't make myself as clear as I should. :)

Let me try to explain where I'm coming from, back in the "old days" of cb we wanted our rigs to work as advertised I guess, 23 channels, 4 watts out on AM and 12 pep on sideband and 100% mod or a tad under, if you increased your mod over that you would bleed over a few other channels and throw telephone & tvi to the four corners of the earth and as there wasn't cable back then you would kill tv reception for blocks around, get very angry neighbors who might recognize your voice and give you an earful or complain to the fcc.
Now as to Amps accepting 4 watts input pwr., the amps back then would accept 4 watts input because the rigs put out 4 watts and depending on the model put out anywhere from 100 to 1.5 kw's.
I use to run and still have somewhere an old Cobra 148 gtx "Export model" which put out 4 watts on Am & Fm and 12 pep on sideband, the signal ran thru a tvi filter to a 100 watt "Black cat" class AB2 Amp, a nice setup for its day with plenty of "talkpower".
We also had double sideband rigs, the carrier is surpressed and the "talkpower" went into the sidebands, I had one and never cared for it personally.
I guess I look for balance you might say, what good is a strong carrier if no one can hear you and what good is it when you overmodulate and kill half a dozen channels above and below your channel plus create havoc on other services? (harmonics)
So there you have the reasoning from the 60's era. :)
I hope I didn't confuse you further?

Master Chief, Roflmao, that was a good one!
 
no not at all , I understand what your saying. When it comes to cb radio I've lived with this and that over the years , I have cb friends close and near , they have radios that swing like theres no tomorrows , Swing Kits ....basically like I run, into there amps of choice , when you talk about TVI and Bleedover ,this i truly understand ,but these guys with there set ups are not ripping there neighbors a part and the scratch from there systems is very small compared to others ,especially channel 6 types , it doesn't matter to them if you wrote it out in granite what would work better for them , they like what they like and they have been doing it for so long , it would take a lot for them to change there ways , there good folks for the most part ,they are not over modualted to ones ear (not a machine) and if they really sounded bad in the first place ,I doubt they would even bother modualting. IM not going to argue with the know -it-alls ....becuase I know there right to a scirentific stand point ,but as they tend to feel about me ,I could care less , this is my hobby and IM not paying them money to make me perform the way there machines tell me I should. For this I am judged ,my radio sounds good and performs well enough for me and the others that talk with me, they do not tell me I sound like crap ,after 20 years around this hobby ,I think I would know if and when i sounded bad or I was coming over my neighbors electric anything. Weather my radios are up to scientific standards or not ? I'd like to think I have plenty of respect for my fellow cb radio operator and especially my neighbors , for the simple fact that I have to live where I live, and IM just to damned old to be an a$$hole where my cb radio is concerned. Thanks MatchBox for the reply.
 

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