Can anyone out there help me? I picked up a Cobra 139xlr 40ch am/ssb base radio that works sweet on ssb, but for the life of me i can't get any decent swing out of it on am. Is there a so called "swing mod" available for these types of radios?
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Swing Mod for 858pll radio Cobra 139xlr
- Thread starter mrblue630
- Start date
Don't look for decent so-called "swing". You won't get it. You WILL get a ton of punchy transmit audio if its tuned correctly, though. Those old XLR's had a really good AMC circuit in them. Its response was almost flat across the usable audio band, and its attack time was almost nothing. VERY good circuit.
Thanks for the input guys. There is no doubt that swing mods aren't the best idea especialy in the wrong hands. (Like most things in life, anything in the wrong hands is usualy bad.)
I know that when the dx was running hot a few years back i spoke to a lot of stations from all across the USA and Hawaii on AM, and i'm sad to say that at least 90% of them that were using cb radios with swing mods didn't sound good. Reason being, (i know that i don't have to explain it to you guys, but for the rest who aren't quite up to speed or just want to know) When you have a real low deadkey and lots of swing, on the receiving end (my end) the combination of swing in the carrier, over modulation, and the skip phasing in and out over huge distances makes it very very difficult to understand whats being said. Some of them had radios deadkeying anywhere between 1/2 watt to 2 watts, swinging to 12 watts(bird) and even more if they were using dual final radios. Well, thats too much audio and too much swing for DXing on AM, might be ok for keydowns but thats all.
So why do i want a swing mod u ask? Well for me i like to have a radio that keys up around 2-4 watts and swinging at least double it's power. So, 2 watt deadkey swinging to 4-5 watts, 3w d/k swinging to 6-7 watts on a bird 43, average watts. That way i'll know that i'll have around 100-110% modulation with little distortion (hopefully). If i can't get that sort of swing out of a radio, and there are no faults with the radio, then i'll try a swing mod. I control my swing various ways, simplest is to back down the mic gain on the radio or power mic.
The cb radios i most like to use are the AX144's, Super cheetah's, followed by the 858pll Cobra's and President's, and then the Uniden Grant's and Cobra 148's. Standard they tune up well with a little bit of swing on AM, i just find that the 858's and in paticular the ax144's too limited.
I know that when the dx was running hot a few years back i spoke to a lot of stations from all across the USA and Hawaii on AM, and i'm sad to say that at least 90% of them that were using cb radios with swing mods didn't sound good. Reason being, (i know that i don't have to explain it to you guys, but for the rest who aren't quite up to speed or just want to know) When you have a real low deadkey and lots of swing, on the receiving end (my end) the combination of swing in the carrier, over modulation, and the skip phasing in and out over huge distances makes it very very difficult to understand whats being said. Some of them had radios deadkeying anywhere between 1/2 watt to 2 watts, swinging to 12 watts(bird) and even more if they were using dual final radios. Well, thats too much audio and too much swing for DXing on AM, might be ok for keydowns but thats all.
So why do i want a swing mod u ask? Well for me i like to have a radio that keys up around 2-4 watts and swinging at least double it's power. So, 2 watt deadkey swinging to 4-5 watts, 3w d/k swinging to 6-7 watts on a bird 43, average watts. That way i'll know that i'll have around 100-110% modulation with little distortion (hopefully). If i can't get that sort of swing out of a radio, and there are no faults with the radio, then i'll try a swing mod. I control my swing various ways, simplest is to back down the mic gain on the radio or power mic.
The cb radios i most like to use are the AX144's, Super cheetah's, followed by the 858pll Cobra's and President's, and then the Uniden Grant's and Cobra 148's. Standard they tune up well with a little bit of swing on AM, i just find that the 858's and in paticular the ax144's too limited.
I'm with you MrBlue630-- too many guys thinking that swing is it and running barefoot radios at like 2 watts swinging to 20 or something like that
If your not running an amp.... why kill the carrier power?
It must be all those "swing kits" on Ebay :roll:
If your not running an amp.... why kill the carrier power?
It must be all those "swing kits" on Ebay :roll:
You said it MB630 and welcome to the Forum ,90% had swing kits huh ? Hmmm , damned cb radios !!! (-: , I use them , for amps for the most part (but the overly extra audio is surely there if you feel the need to put the pedel to the metel) , and I know a handful of folks that use them as well and they all for the most part sound very good !! loud and clear in my ear hole. You said you wanted to swing double your power ? well 2 to 8 / 5 to 20 ect ect at 100% modulation is very much ballpark on bench tuned radios.....give or take a few watts either way. This topic tends to get deep for many , but I would surely think that your 858 chipped radio will give you more then enough swing that you will need at 100% modulation to run power or not , you don't need a swing kit to sound good or bad , as I said ,radio and mic's have mic gains on them for a reason ,weather or not a swing kit is installed in the radio or not ....you can surely turn them down and I would bet a weeks salary that they will sound good and clean to ones ear. IM not talking about machines here but there comes a time that it truly is to ones advantage to at least know when it would be best to turn things down one way or the other. CB radio has been an outlaw hobby for as long as i can remember , and theres a lot of folks out there who have been more then pleased with the way there equipment is set up ...weather clipped this or swing kitted that ...whatever the case maybe ? There's also what is called the correct way or better ways of having ones equipment cared for and worked on. In my personal world of cb radio , the way that works for you and others may or may not work for me ? but in the end ,what really matters is what one is happy or contented with. Do I care ? Sure I do .....but what works for others doesn't nessasarily have to work for me. The 139 is a good radio and you really don't have to do a whole lot to it to work well for you ,some guys just like to play (-: weather right or wrong according to others. Have fun and good luck with your radio. Switch Kit