I have a 148 made in the Philippines (side mic socket). I have channels in it now but when I looked around for mods there didnt really seem to be much out there that I found...just soemthing about an audio limiter which can be cut and one or two pots for power. can anyone direct me to a good site where there might be some nice mods for the 148 GTL to really push it. thanks
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Philippines Made Cobra 148 GTL Mods
- Thread starter iceman78
- Start date
No need to push that radio. A simple tune on those is best. ITS A GOOD AM/SSB RIG ! No need to cut / clip or rip either. You said push it more ? How so do you mean ? The best thing you could do for that radio is put a decent AB amplifier inline with it.
Dont cut this radio up if it's nice! Your not going to have a power house out of this one and you will be lucky to get 20 watts from it. Sale it and get something else.
Let me start off with saying that I am in no way knowledgeable about the insides of these radio's, I use one cause I do alot of driving and noone knows the roads better than truckers, so I like to communicate with them.
I just obtained one of these Cobra 148GTL's and am curious if one of you smart fellas could tell me your opinion of what the 2 toggle switches that someone has installed on the bottom of the radio would control.
If you are looking at the face of the radio, they are towards the right side not far from the faceplate. Very small toggles with 2 selections, left or right, no middle. Thanks in advance.
I just obtained one of these Cobra 148GTL's and am curious if one of you smart fellas could tell me your opinion of what the 2 toggle switches that someone has installed on the bottom of the radio would control.
If you are looking at the face of the radio, they are towards the right side not far from the faceplate. Very small toggles with 2 selections, left or right, no middle. Thanks in advance.
they are for a channel modification.
it is a very common mod for people to do to 148gtl's.
here is a link to a map of the channels you have:
MB8719 PLL
since your switches are left to right, instead of up and down, i dont know which way to tell you to switch them, but i can tell you that to be on the normal 40 channel CB band, you want both switches the same way.
the real way to tell is to use a frequency counter, something that a CB shop would have, but you might be able to tell just by using channel 19 and asking for a radio check.
see, with both the switches one way, you will be on channel 19 when your channel selector says "19", but with the switches the other way, you will be on 27.505 (which could be thought of as channel 50) even though your channel selector says "19".
obviously one of these "channel 19's" is going to be the one with all the truckers, and everyone else for that matter, on it.
the other will be a very quiet frequency, and if you do hear someone on it, they will most likely be in another state. most likely you would never hear anyone on that channel.
so, try the switches one way, key up somewhere near the freeway and ask for a radio check.
if you get an answer you can be pretty darn sure you are on the right "channel 19".
this switch position would be considered "DOWN/DOWN" according to the map i linked you to.
these frequencies can be fun to listen to when the ionosphere is charged and radio signals are bouncing all over the place, so if you go to channel 38 LSB, and you hear a bunch of people talking; try some of the frequencies above channel 40, like 27.475 or 27.555.
remember, transmitting on these frequencies is in fact illegal, but listening to them is perfectly legal.
i would never condone someone breaking the law by talking on these frequencies, even though everybody else does it.
LC
it is a very common mod for people to do to 148gtl's.
here is a link to a map of the channels you have:
MB8719 PLL
since your switches are left to right, instead of up and down, i dont know which way to tell you to switch them, but i can tell you that to be on the normal 40 channel CB band, you want both switches the same way.
the real way to tell is to use a frequency counter, something that a CB shop would have, but you might be able to tell just by using channel 19 and asking for a radio check.
see, with both the switches one way, you will be on channel 19 when your channel selector says "19", but with the switches the other way, you will be on 27.505 (which could be thought of as channel 50) even though your channel selector says "19".
obviously one of these "channel 19's" is going to be the one with all the truckers, and everyone else for that matter, on it.
the other will be a very quiet frequency, and if you do hear someone on it, they will most likely be in another state. most likely you would never hear anyone on that channel.
so, try the switches one way, key up somewhere near the freeway and ask for a radio check.
if you get an answer you can be pretty darn sure you are on the right "channel 19".
this switch position would be considered "DOWN/DOWN" according to the map i linked you to.
these frequencies can be fun to listen to when the ionosphere is charged and radio signals are bouncing all over the place, so if you go to channel 38 LSB, and you hear a bunch of people talking; try some of the frequencies above channel 40, like 27.475 or 27.555.
remember, transmitting on these frequencies is in fact illegal, but listening to them is perfectly legal.
i would never condone someone breaking the law by talking on these frequencies, even though everybody else does it.
LC
I guess changing the value of R196 will drop my DK lower? Right now itʻs @ 1.5-2 watts DK. It keys my amp @ 70-80 watts then swings from there. I wanna lower the DK some more so the amp keys less than 50 and swing from there.
Right now I have VR10 backed all the way down. I think I may need to switch out the Resistor. Anyone have the color codes for a 270 ohms resistor?
I do have a spare radio here I can harvest some parts from.
Aloha, James.......
Right now I have VR10 backed all the way down. I think I may need to switch out the Resistor. Anyone have the color codes for a 270 ohms resistor?
I do have a spare radio here I can harvest some parts from.
Aloha, James.......
yes, lowering the value of R196 will allow you to lower your deadkey more.
do not replace it with a jumper, use a resistor.
lowering your deadkey from 80 watts to 50 watts would lower your signal by almost 1/2 and S unit on someone elses radio.
if your amp is swinging less than about 350 watts PEP, then yes, you should lower your deadkey a bit.
if you are swinging 350 watts PEP or more, then there is no reason to lower your deadkey unless you feel that you are hitting everyone's radio too hard and want to take it a bit easier on them. LOL
as for the resistor color code, Red, Violet, Brown is a 270 ohm resistor.
here is a cool calculator/chart that can be used to figure out the color code needed or find out what the value is of a resistor you are looking at.
RESISTOR COLOR CODE CALCULATOR
LC
do not replace it with a jumper, use a resistor.
lowering your deadkey from 80 watts to 50 watts would lower your signal by almost 1/2 and S unit on someone elses radio.
if your amp is swinging less than about 350 watts PEP, then yes, you should lower your deadkey a bit.
if you are swinging 350 watts PEP or more, then there is no reason to lower your deadkey unless you feel that you are hitting everyone's radio too hard and want to take it a bit easier on them. LOL
as for the resistor color code, Red, Violet, Brown is a 270 ohm resistor.
here is a cool calculator/chart that can be used to figure out the color code needed or find out what the value is of a resistor you are looking at.
RESISTOR COLOR CODE CALCULATOR
LC
My 148s sound excellent and I cut R131 which opens up the AM modulation. Adjust VR11 for 12 watts ssb, you don't want any more than that. Adjust VR10 for 2-3 watts AM key.
These radios sound great with the AM limiter cut. DO NOT CUT TR24 because that'll max out the ssb too and that is a no no. Run a stock mic and you'll be loud.
I know most people on this forum don't like cutting limiters but I have run 148s and Uniden Grants since the 1980s, never heard a clipped one sound bad......except when you try to run a power mic with them.
These radios sound the same whether an NPC mod is done or not.
3 swing 12 watts peak on a 148 is just as loud as my General Lee and it swings 30-35 watts.
There are other things you can do and although these mods will increase swing, the audio won't change.
These radios sound great with the AM limiter cut. DO NOT CUT TR24 because that'll max out the ssb too and that is a no no. Run a stock mic and you'll be loud.
I know most people on this forum don't like cutting limiters but I have run 148s and Uniden Grants since the 1980s, never heard a clipped one sound bad......except when you try to run a power mic with them.
These radios sound the same whether an NPC mod is done or not.
3 swing 12 watts peak on a 148 is just as loud as my General Lee and it swings 30-35 watts.
There are other things you can do and although these mods will increase swing, the audio won't change.