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Kc7qpd
Posted on Wednesday, January 01, 2003 - 8:17 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I just modified the clarifier in this radio, boy does it slide, One complete channel up and one down, so that means 26.955 and 27.415 are there
just doing the clarifier, have not done channel mod, but be aware, the 148 NWST has two red wires
and one black on the clarifier control, this is a china built radio, so heres what I did,
1: cut the black wire at the plug on the main board, and extend it, then solder it to pin 3, of IC-4, its a (KIA 7809P) 9 volt regulator, yes 9 volts. Use your volt meter to make sure you have the right leg!!!
2:Now cut the outer red wire from the same plug,
Extend it and run it to ground, this leaves the middle red wire untouched!!!!
3: cut D52,R44 and take R174 out, and put a wire
jumper in its place.
4: You will have to retune,
L23 AM Frequency
L59 USB Frequency
L22 LSB Frequency
5: After all this you will notice, that the clarifier is real touchy, so here is what I did,
I got a 20k 10 turn pot, and soldered the black
wire from the original clarifier control, to the front tab (the tab closest to the shaft) and the red wire from ground to the middle tab, and the last red wire to the last tab, next I had to remove the crome face plate, and drill the hole bigger so the threads of the 20k 10 turn would fit through, I used a 3/8 th inch drill bit,be very careful not to drill into the wires
on the main board, and when you put new pot in that the black wire is not setting against the
dynamike control, as this could short out the regulator, or much worse, put face plate back on and retune, the freq. cans listed above.

Now the next thing is if anyone knows how to keep the audio from getting fuzzy, if you turn the dynamike up, let me know, I have talked to a few people and they say I sound like Im overdriving,
and the watts are lower then the 12 watts allowed by the rules, Im runng dynamike at 12 oclock, and power mic, at 2, to keep audio sounding good, but not getting the full 12, yes I know about vr 11, been there done that,have fun!!
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Kc7qpd
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Username: Kc7qpd

Post Number: 3
Registered: 1-2003
Posted on Friday, November 11, 2005 - 6:36 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Cobra 148 NWST Channel Mod




Well the Cobra 148 NWST with the MMB8719 PLL
can be modified,But with two switches,

1 get two spst switches


2 On the solder side of the board, locate the trace to pin 14, and cut,then solder a 4.7k 1/4 watt resister across the cut trace, next solder
a piece of wire to the trace that still leads
directly to pin 14, then solder another wire to pin 9, then solder the wires to a switch.


3, next solder a wire to pin 10, and solder one wire to a ground on the board, solder these to a
switch also, thats it, do not try to do the final
switch to pin 11 and 12 as you would with the
regular MB8719 mod, this will take out the
PLL, the MMB8719 is different, You will replace PLL if you try.


4 If you want to do the standard 148 mod to the
148 NWST, you will have to replace the MMB8719,
with a MB8719, than its just like its always been.
Just remember, were not suppose to use those extra
freqs, This is just for your information, since I have not seen any good information for the nightwatcher series 148s, have fun.

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