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Cobra 29LX Changed Again

CbRadiosPRONTO

Well-Known Member
Mar 21, 2014
402
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USA
www.cradiospronto.com
I started a thread back in Sept of 2021 about the Cobra 29LX being surface mount technology. Like other manufactures, Cobra has been hit and miss with inventory and I recently was able to grab a couple dozen of the 29LX. Not knowing what to expect, I opened one up and what I found was a surprise. It wasn’t SMD but it also wasn’t the same board I’m used to seeing.

I fired it up and it was about 1.3KHz off frequency Tx. Meh, it’s AM so who cares, right? But still, it bugs me so here I am trying to find a pot. Instead, here’s what I found. Oh well, I guess it’ll have to stay that way. Why is it whenever I see a Cobra board this clean I feel like they’ve asked for Uniden for help?

On another note, the FM models should be on the shelves in the “next month” or so. We will see.

Oh, and the one pic is just for fun because, let’s face it, the other ones are boring.
 

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What does the box this thing comes in - look like?

Gotta have either a new side panel for point of origin or something to the effect that it can be identified to a newer source.
 
It looks like the PLL and VCO are under that metal cover on the daughterboard. And, is Serial programmed. I wonder if it has 17 or 37 Meg VCO for the RX, and direct 27 Meg for the TX ??
And, looks like the same daughterboard that will be used in the new 29 AM/FM radios about to hit the market.

Not sure if the trimmer to put it back on frequency might be under that metal cover, too.
 
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Ah! ok!

Thx!

So what identifies this, on the box, as being new release, or different from the other LX units out there - so you can find these?
Old box is all black. All of the “newer” 29’s (Classic, Chrome, LX) over the last 1-2 years have some red accents on the top, side; and also show features in red below. (Note: The SMD version from Sept 2021 has no PA and shows as much on the box).

I think I have about 50 of these 29LX radios left but can’t get any more, so far as I know. No MFG date, though, it’s probably in the S#.
 

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If Cobra still uses something close to their old SN# scheme, my guess would be that radio was manufactured in Sept of 22, J being the ninth (skipping I) month indicator.
 
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I started a thread back in Sept of 2021 about the Cobra 29LX being surface mount technology. Like other manufactures, Cobra has been hit and miss with inventory and I recently was able to grab a couple dozen of the 29LX. Not knowing what to expect, I opened one up and what I found was a surprise. It wasn’t SMD but it also wasn’t the same board I’m used to seeing.

I fired it up and it was about 1.3KHz off frequency Tx. Meh, it’s AM so who cares, right? But still, it bugs me so here I am trying to find a pot. Instead, here’s what I found. Oh well, I guess it’ll have to stay that way. Why is it whenever I see a Cobra board this clean I feel like they’ve asked for Uniden for help?

On another note, the FM models should be on the shelves in the “next month” or so. We will see.

Oh, and the one pic is just for fun because, let’s face it, the other ones are boring.
Do you think one of the old expo channel kits would work with that board?
 
I started a thread back in Sept of 2021 about the Cobra 29LX being surface mount technology. Like other manufactures, Cobra has been hit and miss with inventory and I recently was able to grab a couple dozen of the 29LX. Not knowing what to expect, I opened one up and what I found was a surprise. It wasn’t SMD but it also wasn’t the same board I’m used to seeing.

I fired it up and it was about 1.3KHz off frequency Tx. Meh, it’s AM so who cares, right? But still, it bugs me so here I am trying to find a pot. Instead, here’s what I found. Oh well, I guess it’ll have to stay that way. Why is it whenever I see a Cobra board this clean I feel like they’ve asked for Uniden for help?

On another note, the FM models should be on the shelves in the “next month” or so. We will see.

Oh, and the one pic is just for fun because, let’s face it, the other ones are boring.
All were built by the lowest bidder! Their HQ is not far from me and I went there once and there were zero references to anything CB related. They were all about FRS, Cordless phones, and other stuff buy no CB
 
If you can tolerate it's performance - then it should be ok to use, but to "hack" the chip - you'll need to see the proprietary code and then you'll need to decipher that to know what to inject.

Many of you should realize by now that those whom make these are now calling the shots and the technology to make this work is also theirs, so expect to see some really bizarre methods of coding.
 
I'm waiting to get one of the Cobra 29 AM/FM ones as soon as they are available, the AM/FM 29 has the same PLL/VCO daughterboard as this new version of the LX. I have a couple of ideas that should work for channelizing both radios, but not an "A" kit. Or maybe. I won't know until I crack the can on the daughterboard open to see what's inside.

There is the possibility of intercepting the PLL data between the CPU and the PLL, doing fancy maths to the N code, then sending the modified N code to the PLL.

The other idea (my main one) is to use mixers to offset what the PLL "sees" from the VCO, which I need to finish the board design on.
 

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