Tune-up

[MesquiteWx]

Hello all, I am pretty sure I am going to get bashed for this thread and that is not the intention. I am just looking for clarification. I haven't been able to find a straight answer in what is involved in this process and what exactly is done. I know some say it is it boost power but that is not what I am looking for or what I want to do so that is why I am asking. I have seen videos where it looks like they are just tighten up the radio as far as audio clarity and locking in on freq better, then I have read it is to boost power and overdrive it and make it sound like ****. I am not looking to make this illegal or for power gain or anything of that nature. I still want to stay Rule 95 compliant. I don't want to add any mods or add any goofy sounds. I am just curious if these tune-ups help with dialing in the radio to perform better than a barefoot model without them making it illegal or will it just be fine out of the box? Yes, I am aware the antenna plays a major roll in this, but I am curious how much difference this is compared to a barefoot unit.

Let me say I am a ham operator so I don't want this to turn into a debate. The reason I am going to be using the CB is for mobile to mobile communication when the net is reserved for Skywarn and a cell phone isn't practical or towers are jammed and cell service can't get out. Been there, done that. Trying not to get my pants caught down again. We were using just simple Bass Pro special two-way midland radios to talk between vehicles but looking to get something with better range than a mile that's why were looking to step up to a CB that's a little more sturdy and with better range and reliable for general communication off the repeater and net and nothing fancy maybe get 5-10 miles max if possible. I understand a lot of this wishful thinking and depends on the antenna and conditions and that's ok and I know that is wishful expectations and it may not being able to achieve that. Anything better than the mile we get now is a substantial upgrade and I know more than a mile can be achieved. I already have a CB in mind. Just curious has to what exactly is involved in these controversial "Tune-ups" and can their be any benefit if done right and legal if this even exists. Can this help clarity and tighten up the performance of the radio or is it overall just a waste of time. Just want to make sure I do all my homework and research this thoroughly since I seem to be getting mixed emotions and not a real clear answer.

-Thanks

 

[Dawn]

I'm sure not many are going to agree with me and have a problem with what I'm going to post either. Before I do, I've been a licensed and industry certified bench tech in business and marine radio since the early 70's. I also have been an amateur 40 years this year. I've worked for two-way dealerships and merchant marine class commerical marine maintainance companies. We're talking about equipment that spans the quality range from very inexpensive radios such as Ritron and the old Genave/Regency type brands that were in some ways built much cheaper and less durable then average CB equipment to equipment that was essentially derivatives of cost-is-no-object military designs for ship's radio room consoles.

I've yet to ever see a company do sloppy or sub-par alignments on a factory new radio. That also includes CB's that I worked on during the 23 channel days. Sure, with CB's and commercial equipment, you might be able to get some more power out of the radio beyond the recommended output, but that's primarly for keeping the radio within the type acceptance parameters or service it's intended and also keep the compenents within their rated specifications that are often derated so they loaf along rather then stressed to the limits.

You're an amateur. You should understand the relative concept of power vs DB increase. Peak up a radio to the limit and you're stressing the hell out of the radio for just a little more that makes virtually no difference on the S meter on the receiving end. Then we get to modulation. Your theory studies tell you that exceeding 100% modulation produces significant sideband and spurious energy....splatter in other words that causes co-channel interference. Receivers are blamed for being lousy. When the radio is designed for a guard band between channels that no energy should be present in, the companies are free to use wider filters for better fidelity around 6kc wide. Since the guard band is present, there's no reason to incorporate a filter with very sharp side slopes that would dramatically raise the price of the radio. How much does a quality, 3rd party filter with steep 6 db down figures cost compared to a quality amateur radio? Do the math. There's a prevailing concept that the FCC is forcing the companies to limit your modulation. Some chop shop shows you on the modulation meter that the needle doesn't move much beyond the first third to half of the scale and that your radio can be improved. Meters have a ballistic response that has mass and intertia. Look at that same signal envelope on a scope and see where the voice peaks are falling with respect to the carrier. That modulation clipper is there for a reason. Cut it and increase the audio drive and you get splatter....but hey, that guy's also showing you the meter swinging all the way to the right...see, it's a conspiricy against you. Take a look at that signal on a scope and see the distortion and look at the signal on a spectrum analyzer and where all that sideband energy is falling...and that peak job probably is also overdriving the PA and there's spurs and harmonic energy upscale. That all looks like a bigger number on a dumb wattmeter, but how much of it is within the banpass of another receiver? Modulation meters and power meters are nice to have, but thery don't tell you everything. More isn't necessarly better. Then we have the power mic thing. Mandatory among the cb experts. Amplified mics had a reason at one time, to talk further away or compensate for differences in 3rd party or differences in mic cartridge output. Old carbon mics put out heaps of audio, newer dynamic mics replacing the old one needed some extra oomph to compensate. Your radio has an unmodified clipper...ramping up that mic (hopefully) doesn't increase modification, but the amplification into a clipping circuit essentially acts like an audio compressor giving a thicker sound and more average modulation often at the expense of inteligibility. Within limits, it's ok, much like an audio speech processor on amateur radio. Cut out the limiter and you have a disasterous combination.

Another note about peaking. I have no idea of today's designs. Years ago, you could peak some tube radios from 3.5 watts nominally (used to be based on power input of 4W) to well over 15 while stressing the power supply to the max and tube ratings. Problem was the audio modulator in AM didn't have enough power to modulate the carrier fully. I don't know to what extent that exists today, it didn't much matter with most 23 channel solid state sets as you didn't really see more the a watt or two more at max output that the modulator stage could't be adjusted to modulate fully. Overall sum? Zero. So you have a watt maybe two, but would have to double your power output just to get 3db of gain and no real net gain at the receive side to speak of. Your out the bucks mr. golden screwdriver charged and have component failure sooner then later.

No company worth their salt is going to deliver you a radio that isn't perfroming at it's best within the design parameters sold. If the radio was modified, then maybe the PLL might need to deviate from the factory setting to cover the entire territory. Clarifier mods with greater range and transmitter shifting...you're moving into the guard band if the swing is too large, moving too fast unless you put in a reduction drive or multi turn pot to make it useful for it's original purpose for getting better voice color. And, did you ever wonder why amateur radios generally call it RIT? It limits it to the receiver only because if you also have tx shift, it leads to a leapfrogging effect as you tune to clarify another persons slightly off signal, he does the same and shifts his transmitter. Sounds stupid? It is
.
All these mods need to be looked at with a grain of salt. Some mods may be worthwhile as companies try to design a radio with the cheapest available parts. Good quality schottky diodes in a mixer increase receiver perfomance and reduce IMD products in received circuits switched by diodes instead of manual switches when you have a neighbor running a kilowatt. They can soften the harshness of a detector diode or ring modulator/product detector if it's discrete instead of a chip for more pleasing audio. This is 2013. If a company puts in a transistor or FET in a circuit, it's probably going to be as good as it's designed for. In a front end, a gee whiz super FET some chop shop guy adds from cheat book mod he read about that will make him $35 for 10 minutes of work. You might get more sensitivity, but like adding a preamp, you become more prone to interference and intermod. Thirty years ago, you could do some major performance changes with parts upgrades in terms of sensitivity,noise figures and distortion. Times have changed and most mods aren't worth the money beyond bragging rights.

Thirty five years ago, you couln't talk sense into most guys based on the misinformation they get from others who don't have a clue what they're talking about and techs that couldn't do real component level repair then find their @$$ without a cheat book or lots of experience seeing the same problems. The price margin of today's sets are so low, that a real repair isn't worth the investment in equipment and if you have the brains to repair at component level, you can do much better elsewhere. Nobody is going to pay you an honest hours worth of work for a set that barely cost the same if they're that compentent unless they really love what they're doing and have other sources of income to offset the bench labor time.

Hope that answers your question.

 

[robertmac]

Amen.

 

[LtDoc]

Dawn,
That's very well put. Unfortunately, you were also right in that very few people are going to believe you. The myths abound, and will get worse as technology progresses. Somewhere, someone is going to figure out'a way to make a buck from just a tiny misconception. Oh well...
- 'Doc

 

[KC4RAF]

Dawn gave you a really good

summary of increasing wattage vs. db gain. Lengthy, but spot on. The best you can do is get an antenna that works great on a vehicle, of course it'll cost more than a junky cb antenna, but you'll see better range. And getting 5 to 10 miles from a vehicle is VERY hard to accomplish. Money, amps, et al, ...
I've seen golden screwdriver techs do some adjustments, add a component here and there, tweak this, tweak that, and in general the quality of transmitted signal down the drain.
If you had a couple of base stations that maybe had beam antennas, you could employ them in your storm reporting.

 

[wtp]

think long

years ago i worked in suffern ny, two locals would visit me with their cb's mine was also on they claimed nothing beat their k40 antennas until we were listening to ch19 and only my radio had a voice on it. they said no big deal the trucker wanted info on the tappan zee bridge 12 miles away. i said no he wanted upper or lower which was the george washington bridge 20 miles away. i was using a 108" ship so longer is better!

 

[cifd64]

Dawn,
Somewhere, someone is going to figure out'a way to make a buck from just a tiny misconception. Oh well...
- 'Doc

They are called politicians....

 

[LtDoc]

cifd64,
Hey! That's nasty...
- 'Doc