50 watt mod? Gimmie the straight scoop...

[nite-eagle]

50 Watt Mod ? ? ? ? ?

I have been reading so many post's about the "50 Watt Mod" thing and all the comments. My question is this...
Understanding Ohm's Law, how does one get a 4 watt radio to peak out to 50 watts and still be wired with 18-AWG wire using a 2 amp fuse? Thanks for your input into this mystery...
73 and God Bless, nite-eagle

 

[sleepwalker]

Re: 50 Watt Mod ? ? ? ? ?

a 2 amp fuse?[/quote]you will definitely need to upgrade the fuse

 

[Moleculo]

You don't. You replace the power cable and upgrade the fuse.

 

[freecell]

18 AWG wire hardly has to be replaced to handle a few more amps of current. it's rated to handle 16 amps of dc current. some mystery.

 

[Moleculo]

But it makes me look cool when I use the heavy duty 14 guage power cable .

But in all seriousness, a 50 watt class C radio is only going to draw about 5 amps. (50watts / 14 volts / .65 efficiency factor). So get the appropriate fuse and be happy.

 

[redwing21]

50 watt mod

that folk lure is just as funny as a 2pill 2879 amp doing 400 wattspeak bird @14v

 

[C2]

I was wondering about the spectrum analyzer video (that is not a scope, BTW). It looks a little suspicious.

What is the sweept bandwidth set to? It looks like 10 MHz to me.

Looks like that modulated signal totally blasted away the entire 11 meter band, along with the freeband, with higher order InterModulation Distortion products.

?

Also, at a 10 MHz sweep, you would not be able to see even just the second harmonic.

Of course that is assuming the sweep is 10 MHz centered on around 27 MHz. Maybe it is sweeping from 0 to 50 MHz (or there abouts)? Still would not see the 2nd harmonic, and that would make the IMD products look even worse.

You need to use two setups to know what your signal looks like.

One that is much closer in with a narrower sweep, so you can actually see the IMD products. Something like a 20 kHz sweep would probably be nice. A clean radio will have the first order IMD products down to -30 dBc. Higher orders should start to dissapear in the noise.

Second one that starts it's sweep closer to your signal at 27 MHz and stops after the second harmonic at 54 MHz, so you can actually see if its within the -55 dBc spec.

Anyway, I was just suspicious of that measurement.

 

[bcrewcaptain]

I was wondering about the spectrum analyzer video (that is not a scope, BTW). It looks a little suspicious.

What is the sweept bandwidth set to? It looks like 10 MHz to me.

Looks like that modulated signal totally blasted away the entire 11 meter band, along with the freeband, with higher order InterModulation Distortion products.

?

Also, at a 10 MHz sweep, you would not be able to see even just the second harmonic.

Of course that is assuming the sweep is 10 MHz centered on around 27 MHz. Maybe it is sweeping from 0 to 50 MHz (or there abouts)? Still would not see the 2nd harmonic, and that would make the IMD products look even worse.

You need to use two setups to know what your signal looks like.

One that is much closer in with a narrower sweep, so you can actually see the IMD products. Something like a 20 kHz sweep would probably be nice. A clean radio will have the first order IMD products down to -30 dBc. Higher orders should start to dissapear in the noise.

Second one that starts it's sweep closer to your signal at 27 MHz and stops after the second harmonic at 54 MHz, so you can actually see if its within the -55 dBc spec.

Anyway, I was just suspicious of that measurement.

yup, my 50watt radio by FG Best sure is loud....on all the channels....THAT I CHOOSE....
always gonna be a hater

 

[C2]

I was wondering about the spectrum analyzer video (that is not a scope, BTW). It looks a little suspicious.

What is the sweept bandwidth set to? It looks like 10 MHz to me.

Looks like that modulated signal totally blasted away the entire 11 meter band, along with the freeband, with higher order InterModulation Distortion products.

?

Also, at a 10 MHz sweep, you would not be able to see even just the second harmonic.

Of course that is assuming the sweep is 10 MHz centered on around 27 MHz. Maybe it is sweeping from 0 to 50 MHz (or there abouts)? Still would not see the 2nd harmonic, and that would make the IMD products look even worse.

You need to use two setups to know what your signal looks like.

One that is much closer in with a narrower sweep, so you can actually see the IMD products. Something like a 20 kHz sweep would probably be nice. A clean radio will have the first order IMD products down to -30 dBc. Higher orders should start to dissapear in the noise.

Second one that starts it's sweep closer to your signal at 27 MHz and stops after the second harmonic at 54 MHz, so you can actually see if its within the -55 dBc spec.

Anyway, I was just suspicious of that measurement.

yup, my 50watt radio by FG Best sure is loud....on all the channels....THAT I CHOOSE....
always gonna be a hater

There is no hating. I was just observing the presented measurement. The whole point of the video was to prove a point. It is obvious to a trained technical eye that the video proved no such point. It's also obvious that the folks that made the video knew something about the equipment they were using. I just do not understand why they would set it up to disprove the very point they were trying to make?

It's about the numbers, not lip service or smoke and mirrors.

 

[Butcher318]

If there are any doubters you can go to the Communications Experts section of this forum and read for yourself. You can even go to the web site. This is not a 15.00 clip the resistor and bend a coil tune-up we speak of here, there is no smoke and mirriors, a radio that Justin tunes flat out performs.

I talk to a guy on a 2970 most every night at work, graveyard shift. That thing is just plain loud, I have seen it hit 220-230 watts on SSB. There are several other 2970's running from time to time that are much softer and barely hit 160 watts.

There is alot of BS in this hobby and too many shops have lied and cheated people for years. C E is the real deal, they make no claims they can't back up. Thats that.....nuff said.

 

[Lazybones1222]

If there are any doubters you can go to the Communications Experts section of this forum and read for yourself. You can even go to the web site. This is not a 15.00 clip the resistor and bend a coil tune-up we speak of here, there is no smoke and mirriors, a radio that Justin tunes flat out performs.

I talk to a guy on a 2970 most every night at work, graveyard shift. That thing is just plain loud, I have seen it hit 220-230 watts on SSB. There are several other 2970's running from time to time that are much softer and barely hit 160 watts.

There is alot of BS in this hobby and too many shops have lied and cheated people for years. C E is the real deal, they make no claims they can't back up. Thats that.....nuff said.

Yeah - what Butcher said. No butt kissing here - but Justin at CE is the real deal. I got two very nice radios tuned by Justin to prove it.....to me anyways.

 

[freecell]

C2,

a noteworthy observation........i do notice however
in the video someone mentions the reference "1 Mhz.
wide........50 db. below...." did you hear that also?

 

[freecell]

"I did some research a 1969 transistor cant produce what some of you say it will produce........"

the conclusions that you have drawn from your research are faulty because you have not fully understood what you read. minimum, typical and maximum ratings for the 2SC1969 are 16, 18 and 22 Watts PEP, respectively. these figures are derived from operating the device with 1 Watt of Input @ 12 Volts in Class AB Operation. if only the Class were changed from AB to C and nothing else there would be a substantial increase in output, simply because of the increased efficiency when compared to AB operation. we still have the drive, operating voltage and the input/output series impedance matching (extremely important when used as a substitute for the 2SC2029, 2SC2075, 2SC2078, 2SC2166, etc.) parameters to play with to yield even further increases in available output power.

"but I tend to notice there are some people on this forum who seem to have been born smart and never had to ask a question."

maybe some of us have actually had some formal training in these areas and asked our questions a long time ago in a classroom setting or under the tutelage of a mentor, as an apprentice. no one is born knowing this stuff. just how do you expect to get any replies to your questions if there's no one around here with any answers?

and since you brought this up i'll take you to task on this as well. you probably should take "Peepaws " advice but not because we need to know you any better but because you need to take a more thorough approach to your education and present yourself as teachable so that you can learn that which you desire to know. "ragging" on the people here who could assist you in achieving that goal isn't conducive to attaining it.

if for any reason you believe or think otherwise, then i have a few questions for you.

FYI.

 

[freecell]

"It's really simple, check out the voltage that the transistor is supplied during modulation. It's not 12.6 volts, but actually MUCH higher."

quite right. i take it for granted that most realize this but it is worth repeating. thanks, Justin.

 

[C2]

If I was "full of it" dont you think my customers would know it by now?

Well, the cap and resistor mod, along with the limiter clip, has been a main staple for most techs in the US. And what do their customers think of those mods? It's not too hard to fool most "CBers."

Also as far as harmonic content, the radio has a 54Mhz trap built in.

Yes, which will to some extent filter those harmonics. But will it be enough?

As far as IMD products, they're acceptable, especially if the radio is ran correctly, but find me a person that likes to do that. (most people will crank the mic up, and cause flat topping, or distortion, which duhhhh.. causes the IMD products to start to rise)

Which brings me back to the point of, what was the measurement supposed to show me? That the signal was cleaner than a cheesy snip-snip cap and resitor mod? The way it was set up, you would not be able to tell the difference. I mean, it's too wide to really see the IMD products. Too narrow to see the harmonics. I don't believe that it is 1 MHz wide, but I could be wrong?

The rest about it is just lip service.

Also, just to be clear, I am not commenting on your work or questioning the validity of the claims. I'd like to believe it is all peaches and cream. I'm trying to see it in the presented measurement.