tuning & peaking...

I'm not a technical electronics person so i'm sure my explanation of this is going to sound stupid... but basically...

I got a Cobra 25 LTD... Tech took it apart, hooked it up to a meter...
Turned on big screw (ears) so I could hear further... Turned another big something or another (transmit) so I could talk farther... it worked... Between him doing that and putting a little bit taller antenna, I was talking into the next county...

a week later... hooked up a high drive palomar 225... Snipped the wire inside of my radio that connected to my RF gain knob... re-ran the RF gain knob wire to control how many watts I wanted to send into the kicker before it boosts my signal... right now I'm putting out around 400 watts out my little Cobra 25. I get out a hell of a lot farther. I don't know if this makes a lot of sense and like i said, i am not a electronics person but sometimes it sounds like some of these shops make the "peak and tune" sound more technical than it really is so they can make more money... I watched the guy do mine and though i don't know how to do it myself.. it took literally five minutes and then we set my SWR and i was good to go.

 

I believe the "final" is nothing more than the swing mod, which is changing out the resister for a larger one.

 

Funny thread . . . . . .
Plenty of correct info on just about any "Radio Exclusive" forums,each have one or two threads running.

The latest toy is an RFX 75,read up on it.

 

The answers to your questions are as follows:

1-What's the MOSFET final? MOSFET is an acronym (Metal-Oxide-Semiconductor Field-Efect-Transistor). Bottom line, it's just another type of final amplifier.

2-"had big final added": Radio comes from the factory with a final amplifier set to put out a maximum of 4 watts, although it is capable of more. Some shops pull that final out and replace it with one that will put out more RF power than the factory installed one.

3- does tune and alignment mean same as tune and peak...or need all 3? To tune and align a radio properly requires some high dollar ($5,000-or more) electronic equipment. I doubt most cb shops out here have the equipment, the ability to afford, or the desire to spend that kind of money for something they probably wouldn't know how to read and understand the operating manual for, let alone operate the equipment. Plus, most folks would be unwilling to spend the kind of money to have a true tuning and alignment done on the radio (we're talking appx $65.00 just to start). Tune and peak usually is nothing more than turning up the output power on the RF final amplifier.

You want to get your radio to reach further, invest in an antenna that has the highest RF gain in dB {how much power an antennae will handle has no bearing on this}, get your SWR set to as low as possible. Any cb shop that tells you they have you at 1.1:1 you'd better run away from. A reading of 1.1:1 is difficult enough in laboratory settings, let alone outside of a lab.

Hope this helps.

 

You were doing alright till you got to the SWR Flat 1.1:1
Not all antennas can be tuned to 1:1,but to claim "it cant" happen is absurd.

 

The more efficient an antenna, the less likely it will tune flat across the band. I can tune a radio to nearly 1:1 into a purely resistive dummy load across the band, but it won't transmit any further than a few feet from the load.

Also, CB's, by design will not tune flat across the band. If set correctly, it should peak out in the middle of the band. That's why channel 10 used to be the popular channel on the old 23 channel radios, since it was near the middle. Then when the band was expanded, channel 19 became the most popular. That's where I would want my radio to be at max.

About twenty years ago I tuned my dad's old Johnny I to peak at 10 watts (with mod) on channel one, as there was a group of us that hung out there. The highest channel crystal that was installed was channel 11 and it dropped off quite a bit to about 7 watts. If I remember correctly, I could approach something that was kind of flat, but then it was closer to 7 watts even at the peak.

Disclaimer:
I used to be a commercial two-way radio technician, and admit that I am very rusty on the latest technology. However, RF radiation and general radio theory haven't changed.

 

Guess folks with "CB's"will just have to wonder aimlessly looking for the SWR Grail.
I know what my meter reads and my "Digital"radio's STOMP barefoot and the rest would be described under an R rating.

 

I didn't say it couldn't be done, just that it would be very difficult. My point really was that one needs to be extremely careful when using "CB shops". Too, too many of them wouldn't know a diode from a variable rheostat.