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Peel 'N Stick variable key for the Cobra 29 radios. No joke.

Depends on how skillfully the MOSFET conversion was done.

In a stock radio you will lose about a half Watt of carrier with the control maxed, compared to the carrier power before it's modified. Peaking a stock radio for max modulated power usually gets you between 4 and 5 Watts of carrier. Losing a half Watt from that is not usually a problem.

If a MOSFET-modded radio can only get a couple of Watts of carrier after the conversion, you'll only have a max of 1.5 or so with the module installed.

MOSFET mods are all over the map, so that's about the only blanket statement I can make about them, that they're not all created equal.

73
 
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I was wondering if anyone (tech) on here that I could ship my new 29 Chrome to and have this installed. I don't have the kit. So that's needed too.

Was thinking on the delta tune knob maybe. Least used on AM imo.

Please feel free to IM me.
 
Simplest way is to hijack the SWR Cal control. The normal resistance value is 5k, the value of the pot that's packed with the kit. Just unhook the SWR wires from the Cal pot and move three wires from the kit to the Cal control.

The control we include fits in the front panel of most Cobra 29 radios, but moving three wires may be less work than unbolting the old control, to install the new one. Faceplates on all radios are not created the same, and will have to be removed to change a control on some of them.

73
 
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nomadradio said:
Depends on how skillfully the MOSFET conversion was done.

In a stock radio you will lose about a half Watt of carrier with the control maxed, compared to the carrier power before it's modified. Peaking a stock radio for max modulated power usually gets you between 4 and 5 Watts of carrier. Losing a half Watt from that is not usually a problem.

If a MOSFET-modded radio can only get a couple of Watts of carrier after the conversion, you'll only have a max of 1.5 or so with the module installed.

MOSFET mods are all over the map, so that's about the only blanket statement I can make about them, that they're not all created equal.

73
Click to expand...

Stuck on 1.5 watts was exactly what happened with a recent purchase of a Cobra 29 that had an IRF 520 mosfet mod.

A tech put the variable in, and could not get it to go past 1.5 watts which was what it was keying in the first place. Finally, he got 1/2 more watt by putting a capacitor on the back of the board for the driver final...he says. Variable worked, but was only a zero to two watts variable which I thought was silly.

Anyway, I ended up having the mosfet mod removed, and had a HG 2SC2312 installed. Now the variable works good. Tech friend of mine even installed a pot inside of the radio where I can set the low carrier on the variable.
 
Last edited:
snippits75 said:
Stuck on 1.5 watts was exactly what happened with a recent purchase of a Cobra 29 that had an IRF 520 mosfet mod.

A tech put the variable in, and could not get it to go past 1.5 watts which was what it was keying in the first place. Finally, he got 1/2 more watt by putting a capacitor on the back of the board for the driver final...he says. Variable worked, but was only a zero to two watts variable which I thought was silly.

Anyway, I ended up having the mosfet mod removed, and had a HG 2SC2312 installed. Now the variable works good. Tech friend of mine even installed a pot inside of the radio where I can set the low carrier on the variable.
Click to expand...

I was afraid of this...

The Driver may not be able to develop enough power to drive the MOSFET - not without help...

Because if they do the MOSFET conversion using those "Self biasing" types - the ones with the "Diode Resistor and a Second Resistor" may need to take a small amount of Nomads' Bias line and work it over to the part to feed some power into the "self-bias" part and make it generate enough trickle voltage to make the MOSFET start building power. A simple 10K to 15K 1/6th watt with Ferrite Bead and tacked on to the Diode Banded end will do.

This thread - Click Link - may help to add more answers...
 
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Thats cool. Is the max deadkey the same as stock or about?
I'm more curious about the power output than the swing mod.

Thanks for your reply.
 

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