Cobra 25 LTD mods?

[red97k1500]

The KL35 is a complete waste of time. With a nice peak and tune you should e able to see 25 ish watts from either radio. Spending all that time de-tuning them to run with that dinky amp to only gain 10 watts is not worth the time. You must double your watts for anyone to even notice.

If you really want to do a mod on one of those radio's search here for the 50 watt Cobra 29 mod. The same should apply to your radio's for the most part.

Has anybody ever even gotten an honest 50 watts out of a cobra 29/25, pc68/78 style radio? I’ve seen a lot of debate about it, but don’t recall seeing any definitive answers.

 

[Handy Andy]

The effort to make it 50 watts, you have to look at just how much is going into the channel you're on, versus the extra undocumented abilities to generate spread spectrum signals.

Well, I'm gonna' do some math...

Ok, 50 watts - Volts X Amps - or W = V x I

We know 13.8 are you ok to round this to 12? Referring to Voltage...

We'd have to rewrite the equation to solve for I - the total amount of amps required..

Or...

I (Amps) . = 50 (W) / 12 (V)

IF you see where I'm going with this - since others have done something similar - you should have already arrived to an answer that questions the ability to achieve that wattage from the initial starting of 4 watts into a 4:1 ratio.

(It's just over 4 Amps) <<<-- And we haven't even touched on the conversion efficiency

On top of, the level of copper thickness and the ability of said trace to handle the expected current...

So in a way, you can approach it, but not truly achieve it...

Even with the "Stock" final - if you're expecting 35 Watts - you're already pushing Ohms law - and if you're not careful - awakening Murphy's Laws...

Spoiler: Murphy's Law On Relatives

In The Event Of Ever Coming Across A Long Lost Aunt Or Uncle
That Produced Large Quantities Of Offspring Known As Cousins,
You May Find Yourself Enlisted And Charged As A Financially Responsible God-Parent Without Prior Consent

• we are dealing with a Class D device with Class C biasing...
• Class D being Collector Applied Modulation in two stages.
• You can go up in Voltage to approach Breakdown Limits...
  • But that only gives you Power conversion using a Voltage effect for multiplier...
  • You can't push more current into it - only more voltage can be applied and current can follow but only to a certain extent.- Based more upon Ohms' Law. - let alone physically observed results.

If you can understand the above, then you would also know of another effect that is dealing with power consumption and the emission spectrum of that power.

• Hint: It's not exactly Confined to a frequency or even a band
  • But a local Garage Band may be interested in acquiring or integrating your equipment when it interferes with their ability to make music.

I'm talking about not all of it goes to the frequency and not all of it is even RF - e.g. - Heating...

So 50 watts on a meter is as some would say, Ghost Watts - which is pretty much a reaction from all those people that have to put up with what that thing is putting out and letting you know that you are now First In Line at the Worked All Neighbors Awards - which appear right after the Oscars, Emmys', and the I Just Got My Bunions Removed And I'm Happy For It - Rewards Show - after that Late - Late - Late - Night - Shouldn't You Be In Bed By Now - Movie.- which may wind up being Pre-Empted by the Local News broadcasting the address of the offender for the Local Lynch Mob (half - Crazed On Cough Syrup - Due to COVID-19) to appear and celebrate with a wild party no one else expected to have happen since SXSW got cancelled - let alone survived...

I could add more...

 

[guitar_199]

I once heard it said: set the radio to work within it's limits....as it was designed. If you still want more power...... get a decent amp. It will be cleaner....

 

[9C1Driver]

Has anybody ever even gotten an honest 50 watts out of a cobra 29/25, pc68/78 style radio? I’ve seen a lot of debate about it, but don’t recall seeing any definitive answers.

As a general rule no probably not. Some will get into the 40 watt range, if it was my radio I would not do all that to it. You seemed like you wanted to try some mods so I made the suggestion.
Like Shadetree stated above, the KL203 is probably the best bang for the buck in amplifiers. With very little effort you could set a Cobra 25 up to work well with a KL203.