Copper Talk » Ask The Tech » General CB, Ham & Mur's Radio Related Questions/Topics » To tune or not to tune... « Previous Next »

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Buddyboat
New member
Username: Buddyboat

Post Number: 3
Registered: 1-2006
Posted on Wednesday, January 18, 2006 - 10:06 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hello, I'm getting a Galaxy 2547 for the home and two Cobra 148 GTL's for the cars. I will only be using these cb's in SSB mode. Do I really need to pay the extra $$$ to get these tuned???
I'm new to CB's and don't understand the tuning deal.
Thanks alot for any help,
buddyboat
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Tech808
Moderator
Username: Tech808

Post Number: 9007
Registered: 8-2002


Posted on Wednesday, January 18, 2006 - 11:14 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Buddyboat,

WELCOME TO THE COPPER FORUM!

There should be no reason / need to pay the extra $$$ to have them tuned for the use you describe as they will work GREAT!

Lon
Tech808
CEF808
N9OSN
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Hollowpoint445
Senior Member
Username: Hollowpoint445

Post Number: 1023
Registered: 6-2004
Posted on Wednesday, January 18, 2006 - 12:26 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Before you pay to get anything done, I'd use them for a while.

Usually "tune" means to peak the transmitters to their maximum power ouput, and it's not worth the money. On the other hand, an alignment done by a competent technician can improve the radio's receiver performance and that is worth the money. Especially for a SSB radio if the alignment includes frequency adjustment.
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Bruce
Senior Member
Username: Bruce

Post Number: 3427
Registered: 9-2003
Posted on Wednesday, January 18, 2006 - 2:39 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

done by a competent technician

Thats the problem .... they are hard to find and thoes with the test equipt. to do it right are even harder ....
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Moonraker
Intermediate Member
Username: Moonraker

Post Number: 134
Registered: 3-2005


Posted on Wednesday, January 18, 2006 - 8:29 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Galaxy 949/959/2547
VR 13.....SSB ALC (modulation)
VR 14.....AM high power
VR 16.....AM modulation
VR 17.....SSB power
VR 18.....AM low power

What most shops call a peak and tune is turning all of these wied open, and the bad part they rip people off by charging $25 to do it. If you have a watt meter you can do this your self, even if you dont have a watt meter you still can.

On your galaxy, turn your rf power knob (on the face of the radio all the way up, set the AM high power(VR 14) at about 6 watts. Turn the rf power knob all the way down and set your AM low power(VR 18) at 2 watts. Turn the AM modulation(VR 16) wide open. I cant remember which way is wide open, but is you turn it fully in one direction and your modulation meter on the radio doesn't swing when you talk into the mic, turn it the other way. When you know which way is wide open, do the same to VR 13 & VR 17.

You can find the info on your other radios, on the lower left hand corner of this page, click on Modification List (under tools).
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Hollowpoint445
Senior Member
Username: Hollowpoint445

Post Number: 1025
Registered: 6-2004
Posted on Wednesday, January 18, 2006 - 9:50 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I agree Bruce. That's why I started buying my own equipment and I do it all myself. If I had a couple more pieces I could do a full alignment, but at least I can put the radios on frequency, adjust the AMC/ALC and peak the receivers a little.
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Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 1073
Registered: 9-2004
Posted on Sunday, January 22, 2006 - 7:10 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

hollowpoint, what are you missing to do a full alignment?
matt
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Hollowpoint445
Senior Member
Username: Hollowpoint445

Post Number: 1038
Registered: 6-2004
Posted on Monday, January 23, 2006 - 8:53 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I can do a partial alignment, but I can't do a full alignment with test equipment. To do that I'd need a frequency counter that is both accurate and stable, and a VTVM.

An oscilloscope that directly reads the output frequency would be nice too, but I can use my station monitor to look at the modulation envelope.

I can adjust the TX/RX frequency probably more accurately than a frequency counter using my HF rig (synchronized to WWV) as a reference, but it only adjusts the receive/transmit frequency and not the synthesizer frequency itself.
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Sparkomatic
Intermediate Member
Username: Sparkomatic

Post Number: 390
Registered: 10-2002
Posted on Tuesday, January 31, 2006 - 8:34 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The Cobra 148 GTLs won't do much of anything unless they are peaked. Radios that are not peaked sound as flat as a board. SSB performance would be pityful at best. If the radio is on frequency then just have the modulation opened up. I don't understand all the talk about oscillscopes but if you want to make a radio sound impressive open it up, if not....leave it stock and sound like you have a $25 radio.
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Hollowpoint445
Senior Member
Username: Hollowpoint445

Post Number: 1060
Registered: 6-2004
Posted on Tuesday, January 31, 2006 - 8:03 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Other than frequency error, I think most SSB radios sound just fine on SSB right out of the box. With the huge filtering advantage of SSB, touching up the ALC is usually not as beneficial as adjusting the AMC for AM.

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