$25 Tune vs $40 Tune

whos it buy? and can they tell you what your getting, i think a lot of it depends on the radio, i mean certain radios will only do so much.... if a $25 tune gets it to that point... no reason to pay more.... it all depends ... on a lot of things...

 

Depends on the radio.

If you have an export model with ssb/fm/am & it operates beyond regular cb channels, there can be a bunch of retuning or at least checking the tuning. Tuning one of these might take upwards of 30 mins if you go over every single adjustment a couple times.

If it's just a Cobra 29 or similar, a tune-up is quick & easy...unless someone has performed a crappy realignment before you.
Usually a tune-up/realigment on a Cobra 29 will take 15 mins inc. removing the covers.

Many times, a tech will find a circuit in a particular series of radios that he can improve the perfrormance of & might automatically incorporate that change for the price. He'll either use a different order of tuning than the factory or he might replace a transistor or other components to cause the improvement.

The degree of improvement might be as slight as lowering the rcvr noise floor or changing the tone quality of either the transmitter or receiver.

It's hard to say what each tech's fetish is when it comes to his particular idea of how that radio should operate.

If you're not going to get any parts replaced on a Cobra 29 (or similar), $20 is all I'm willing to spend on an alignment.

** Because exports cover a very wide band of frequencies there's a possibility of an incorrect alignment that causes spurious emissions. This is when the radio is transmitting noise or a carrier on a frequency that your channel selector is not tuned to. This is wasted transmitter power that can distort your signal on channel or make the final hot.

The "spurs" as seen on a spectrum analyzer can show up anywhere even outside the bands where the radio can normally operate. You can't know this unless you have a spectrum analyzer.

I don't know of too many shops that have a spectrum analyzer because they are a tad pricey. Don't confuse this device with an oscilloscope. They're not the same although a couple scope manufacturers do make a "plug-in" to change the 'scope into a spectrum analyzer.

 

This would be impossible to answer without knowing what the tech is offer different with the $40 then the $25...

 

As others have mentioned, it depends on the radio and who is doing the tune. I've seen shops charge $25 for a tune and it only involved swapping out a $3.00 resistor or speading some coils. If you look at those various "swing kits" on eBay that people charge $12.00 for, you can get those same parts at Radio Shack for less than $5.00

 

A resistor, a diode & a cap.
Hardly worth even doing actually.
Just cuts your range & makes you sound garbled in the distance.

 

Spend the money on a good SWR and modulation meters, and maybe a field strength meter and learn how to use them (it's simple). The SWR meter will tell you how well your antenna system is matched to the radio. Lowering the SWR numbers can often do much more good than a "tune-up" (and save your "finals"). A tune-up does not affect SWR, so don't expect a tune-up to "fix" an SWR problem (that's an antenna function). If the modulation is over 100%, you're just losing part of your total available power to distortion and noise... cut it back below 100%. Why does 100% modulation mean 100%? Because it's the most efficient value for any signal! Anything higher or lower is LESS efficient, not more efficient! Increasing modulation DOES NOT increase peak power output (watts). A field strength meter will help tell you what direction you are transmitting in. Transmitting off to the sides (common problem) will not give you the greatest forward range.

 

I'm having a few problems I wasn't planning on encountering. I swapped out my OEM International antennas with Wilson FGT-4's. I hooked up each antenna seperately with a coax cable and measured for SWR. SWR looked good on both so I then hooked up my real coax in my truck. Now my SWR is completely out of whack and above 3 on every channel. I can't make sense of it. I have checked for continuity and that all seems ok as well. I really don't want to have to take it into the shop but I also want it working properly.

 

It sounds like a problem with the coax... i mean you can try tuning it with the correct coax in place and see if that drops it that much, but it sounds like a lot. maybe the connectors are messed up. or maybe something else happened. its probably the coax, try replacing it ( i hope its rg59 cophased cable)

 

Well, after you set SWR on each antenna then hooked them together did you set the SWR again?

If you choose to do it that way then this is what you need to do...
Set antenna 1 SWR
Set Antenna 2 SWR
Hook them together then set SWR by trying your best to move each antenna with equal movements...