Cobra Sound Tracker - Opinions?

IMO they are garbage. Cheaply made and that SoundTracker function is only marginally useful IF you are talking with another SoundTracker- equipped radio. That you have had success with them is most unusual. Everyone I know that ever had one dumped it ASAP.

Such piles of crap they were that Cobra discontinued them as soon as they possibly could. Much like the old "plus' series, this is something that Cobra wants everyone to forget ever existed.

Avoid them by any means necessary. Especially on ebay, the home of the misrepresented radio.

 

I have a 29 with sound tracker and one without. When I was running a Nashville turn, one of the other drivers had a 29 with ST, so I would use it talking to him, as we ran out the same time. Now I run a Birmingham turn, so I use the one without ST or I just leave the ST off. Not a big deal, really.

 

Most consider the 29's and 25's with ST to be the worst Cobra's ever built...I also had a 29 that not only had ST...But also had the weather channels...It was considered by most to be even worse!

That said, I never had a problem with the ST feature, but that may have been because I never let anyone in the back of the radio with their Golden Screwdriver either...

 

My 29 with NightWatch, sound tracker and weather is about 6 years old. Never had any problems with it. Everything works just like my LTD. Same range on tx and rec. My friend is using it because he can't figure out his 3300 Connex. By the way I've bought 2 like new Cobra 29s on ebay and three Realistic cbs New Old stock in the box. All perfectly good radios less than $20 each, including shipping. Included were mic and power cords. The secret is still the antenna and coax.

 

The ST feature is like a compander. During transmit it acts like a compressor and it prevents most overmodulation in the + and - directions. During receive it expands the compressed signal. I never had a problem with it, unless one considers not being able to grossly overmodulate and overdrive a problem. Like many other things, making it proprietary rather than open for the industry limited its potential.

 

M818 nailed it -- it's a compander circuit. "Compander" is as sort of contraction between "COMPression" and "expANDER". In TX mode, the compressor circuit selectively boosts the levels of the audio frequenies where voices live -- mostly around 300 to 2,700 Hz -- and hits the modulator with that boosted level, plus the regular noise that regularly accompanies AM transmissions. At the receive end, the Expander circuit again filters that 300 - 2,700 Hz range and "expands", or amplifies it, more than the accompanying the audio noise from ouside that magic band of frequencies where voice lives.
Note: There is lots of voice stuff that lives outside the 300 -- 2700 Hz frequency band, but that extra bit contributes more towards having a hi-fi, "broadcast audio quality" sound. But since CB and other two-way radio systems are designed to send and receive (and please excuse the wildly inappropriate description here) "Intelliegence" -- the part of the voice that carries the actual word information that we're hoping to get across in a conversation, the high frequency sibilant "S" sounds and the Barry White bass components of the voice are useless for our needs.

So if you've got a radio with SoundTracker and you have it enabled, and you're talking with someone who doesn't have it, you'll sound kinda "blasty & tinny" because of all the extra volume packed into that voice-band frequency range. When the other guy answers, you'll hear wide spectrum noise in his signal that your radio expands -- loud voice, loud noise that he transmitted along with his voice, etc.

If *both* of you have ST enabled, the radios will work somewhat like the manufacturer intented -- higher signal-to-noise ratio, so (in the absence of mega-zillion-watt useless stations on the same frequency and within range of either of you -- you'll be able to carry on a usable conversation for a greater distance.

Companding didn't arise out of CB marketing departments; it's long been used in "voice grade" telephone circuits, to keep average levels high but still have an upper level cut-off of loud signals to minimize "cross-talk", or noise from one phone line being coupled into other physically close phone lines (like other pairs of phone lines in a large cable). But most phone line companies have seemingly boundless resources for installing gear to make sure that *everyone's" levels are great, not to mention all the switching and distribution gear they've incorporated into their networks.

I've got two Cobra 29 WX ST NW (I can never remember the order of the initials) variants and three verions of the Cobra 25, two of which have ST. As long as I remember to only use ST at the same time as it's being used on the other radio (if I'm talking withing my own household's memberrs), life is good. Much like older Motorola VPA (Voice Privacy Adapter, their analog scramblers), switching to it it usually enetails asking if the other person has it, then agreeing to engage it.

As long as the rest of an ST-equipped radio is working properly, then blaming its presence for a whole raft of problems with the radio is either a matter of a lot of people having lemons, or radios that've fallen prey to a Golden Screwdriver equipped with his flush cutters and #49 pilot lamp as a tune-up "bench".

That's just my two cents.
-- Handlebar --

 

That bad? I liked my WX Cobra and Uniden....I had the 25 LTD classic and the 68 LTW.......good little radios