Negative Peak Compression boards for Cobra 29

Simply shows sites like this are being combed for concepts others will try and make a $$$ or two...

Sigh, hope @nomadradio isn't upset over something like this.

I saw those boards on e bay and was going to do the same post. Pretty neat idea and they look good in the radio. I wonder how they work?

Look closely - they are a JP36 and Variable Power hybrid.

I saw these too but they quickly sold out. This much be the next batch. Because they replace jp36, they are in series with the modulation and I don't know if NPC can really be done this way. I wonder how well it can recover the carrier between peaks? The picture they show is described as NPC like. The little board looks like it has two transistors and some inductors and capacitors on It? I am going to get some to try too.

I see Q1 and Q3. Where is Q2?

The only information we can glean from the pictures used to show - Q2 must me underneath - as shown in the photo the site supplies to promote the product. At least they are honest, one of the mounting holes show a standoff - but the Dimmer Pass Transistor that comes with the radio - is buried (covered) underneath - at an offset to a different location but covered by this board - so to me this signals that there are more SMD work underneath

The board itself looks to be incomplete install - on purpose, for if they were to install the Variable, those 3 terminal holes below the trimmer pot, it appears that they would then take place of that trimmer, which I can only presume is the actual carrier level setting - so it tells me there's more support (jumper header for example) to add on this board for external variable control.

here what it states on site=
Cobra 29 Variable Power Control Negative Peak Compression

This listing is for 2 boards.

Simple SMD (Surface Mount Device) board, boosts peak and average power compared to old super modulator kits.

Adjustable board mounted variable resistor allows Dead key adjustment.

Prevents/Reduces Over modulation negative peaks. Old school Super Modulator kits would allow Negative Peaks to drop to ZERO watts output. This causes a loss of average power, and higher distortion levels of your transmitting modulation.

NO electrolytic capacitor that could result in power loss because of ESR (Equivalent Series Resistance). This is how other variable power kits can cause you to loose peak power once installed.

Uses Power Metal Oxide Technology to give the highest possible peak power output.

Bonus: Instructions on how to use variable control in front of radio, for adjustable dead key. It's designed into the SMD board!

Simple three wire hook up.

Drill a mounting hole, hook up three wires, and it works.

This may be a less expensive modification that has similarities to asymmetrical modulation. You may even consider it negative peak compression.

Although this board may adapt to multiple AM model CB radios, instructions only included for Cobra 29 CB radios.

Comes with Mounting screws and brass stand off.

Heads up: board take GND from chassis, in most of the cases it's separated from negative power supply. Board won't work. Imo should be insulated from chassis, + and - provided from proper place.

I think it’s basically the same thing Nomad makes and sells.

I’ll support Nomad. It’s intriguing but...

Hey!?

freecell said:

Click to expand...

Hmmm...

Looks familiar...
Maybe this would help shed more light on this...

Doesn't appear to need a connection to the radio's circuit ground. The pad marked "ground" goes to the chassis, not to the circuit board's ground. Every trick I know to do this needs that connection.

Got me baffled. Gotta buy one next time they come up.

73

Power Metal Oxide Technology: Great way to glorify a MOSFET all-be-it lateral it is still a MOSFET just say so but like Nomad said I would buy one or I guess 2 and make a video I, have a 29 here that is just waiting for an experiment.

Same guy that made the galaxy pill board. Xbones