I am getting my radio tweaked and peaked for $20 from a guy in NV. If it works well, I will let you folks know. He advertises on the Pirate board in the vender section.

Radio? CB or AM/FM?


"TSUNAMI"
1969 Nissan Patrol
Chevy S-10 Springs(PUP springs were too short!)
FJ-40 Rear Axle
Original driveshaft, slightly modified
Custom shackles
75,000 Original Miles!

It is a cb. and that is a good rate for I used to pay $20 just to look at a radio, that was back before I learded what I was doing.

I can't find any documentation online on tweaking the radio I got... I can find it for every other radio on the face of the earth I swear, just not mine (Uniden PC78LTW)


DripSpeed Merchandise

Did you find one for the Cobra 25LTD Classic, by any chance?


"TSUNAMI"
1969 Nissan Patrol
Chevy S-10 Springs(PUP springs were too short!)
FJ-40 Rear Axle
Original driveshaft, slightly modified
Custom shackles
75,000 Original Miles!

25 GTL/LTD/CLASSIC

Modulation VR5 or CUT D9 Power L13, L10, L9, L8
AM LIMITER: D-9
POWER TWEAKS:
1. Change R76 (3.3k) to a 1k (located near mike socket)
2. Change R43 (10 Ohm) to a 2.7 Ohm.
3. Change R108 (1 Ohm) to a .47 Ohm.
4. Replace stock final with a 2SC1969 transistor.
5. Re-tune coils L10,L9,L8 for maximum forward power.


MODULATOR
PARTS NEEDED: 1- 220uF (16 to 25 volt) electrolytic capacitor.
1- 100 to 200 Ohm resistor. (1/4 to 1/2 watt)


ASSEMBLY:
1. Make sure your radio is peaked out.
2. Unsolder JP6 near final.
3. In JP6 holes, solder the 220uF capacitor. (negative side of cap. faces final)
4. On the solder side of the board, solder the resistor across the 220uF capacitor.
You can use different resistor values to get the desired dead-key.


VARIABLE POWER:
1. Find the two wires that are attached to the RF gain control, follow them to the PC board and UNSOLDER them.
2. Solder in a jumper wire from where you removed the wires on the board. This will restore receive.
3. Place the two wires from the RF gain control in your mod kit by soldering one wire to each of the 220uF capacitors leads.

found a 25 LTD Schematic, enjoy
http://www.714xpress.net/25ltd_sch.html

Man finding a mod for a Uniden PC78 is not an easy task but I came a crossed several sites that said it is the same as a cobra 25/29 (just don’t remove any capacitors). So hear is what I have handy to get you started. The 25s mob are listed above, but I do have the 29’s if you need them. Just let me know.


Radio Modulation Power
25 GTL VR5 or CUT D9 L13, L10, L9, L8
25 LTD VR5 or CUT D9 L13, L10, L9, L8
25 LTD Classic VR5 or CUT D9 L10, L9, L8
29 GTL VR4 or CUT D11 L14, L13, L12
29 LTD VR4 or CUT D11 L14, L13, L12

All this tweaking and peaking is fine , but how do you shieldyour FM tuner from it( or TV)... seems like it transmits to more than than just the CB, uno.

.....................
'98 FAD FrontyKC
147,000 miles
Packin ARBd 9" Tornado w/ Dual Remotes;-)

ok Im so totally lost right about now. Are you guys talkin bout CB Boosting. And isn't it non-legal kinda? Or is it non legal for you to use a black box to boost a base cb radio?

.:|SpaceMonkeyMafia|:.
you may be a king or a little street sweeper but sooner or later you'll meet the reaper

Thanks, Robert, for all that... uhhh.... stuff? Ill print it off and have my uncle translate it for me. He knows ALOT about CB's and has repaired his own several times.


"TSUNAMI"
1969 Nissan Patrol
Chevy S-10 Springs(PUP springs were too short!)
FJ-40 Rear Axle
Original driveshaft, slightly modified
Custom shackles
75,000 Original Miles!

Hey there...

Here's a link to a specialty company that has a pretty good reputation. Also, they sponsor a BB for radio stuff that is pretty good.

http://www.pacetronics.com/

Rob

www.nissanoffroad.net

Cool!


"TSUNAMI"
1969 Nissan Patrol
Chevy K-10 Springs(PUP springs were too short!)
FJ-40 Rear Axle
Original driveshaft, slightly modified
Custom shackles
75,000 Original Miles!

quote:

---

Originally posted by BoneCrusher:
ok Im so totally lost right about now. Are you guys talkin bout CB Boosting. And isn't it non-legal kinda? Or is it non legal for you to use a black box to boost a base cb radio?

.:|SpaceMonkeyMafia|:.

---

Hey there...

There are both legal and illegal things that can be done to a CB. The key thing is that it cannot transmit more than 4 watts I think it is. However, modulation is at a greater watts than this 4 watt, dead key carrier. Modify the 4 watt dead key and I am pretty sure that's illegal.

The modulation can be modified by several means. At the first level, internal components can be modified or replaced. On a high quality CB, this can possibly swing the peak power at modulation to something towards 20 watts. As an added kicker to modulation, external amps can be added to both mobile and base stations. These amps can boost modulation from several hundred to several thousand watts.

Keeping in touch with the legal things... I think that adjustments that affect frequency have to be performed by a FCC licsensed tech. Other adjustments, I think, do not require a FCC tech.

Rob

www.nissanoffroad.net

quote:

---

Originally posted by Hootowl:

quote:

---

Originally posted by BoneCrusher:
ok Im so totally lost right about now. Are you guys talkin bout CB Boosting. And isn't it non-legal kinda? Or is it non legal for you to use a black box to boost a base cb radio?

.:|SpaceMonkeyMafia|:.

---

Hey there...

There are both legal and illegal things that can be done to a CB. The key thing is that it cannot transmit more than 4 watts I think it is. However, modulation is at a greater watts than this 4 watt, dead key carrier. Modify the 4 watt dead key and I am pretty sure that's illegal.

The modulation can be modified by several means. At the first level, internal components can be modified or replaced. On a high quality CB, this can possibly swing the peak power at modulation to something towards 20 watts. As an added kicker to modulation, external amps can be added to both mobile and base stations. These amps can boost modulation from several hundred to several thousand watts.

Keeping in touch with the legal things... I think that adjustments that affect frequency have to be performed by a FCC licsensed tech. Other adjustments, I think, do not require a FCC tech.

Rob

http://www.nissanoffroad.net

---

Or you can just do whatever you want because this is America. Mine is now capable of 25 watts, and is much loader and will blow your mic up if I want it to.

Ok to make this clear, it is 4 watts dead key and you can only have 60% modulation. So out of the box most are at or past legal. A black box of any kind is not permitted. The extra frequencies are only illegal if you key on them. Now for the FCC, as long as you don't cause a problem they real don't care. Well to tell the truth they are under staffed and CB is not that important to govern it any more. The only thing that you need to worry about is the 10 meter band which starts at 28.045 MHz. The best mod I have seen on a radio goes from 26.000 to 30.000 MHz. and those are rare. You can buy radios that can do a lot right out of the box known as exports. Most are 6 to 8 bands, a few do 12 to 15 and wattage most of the time are 10 watts and do go to 200 out of the box.

As for working on the radio, anyone can do it.

To prevent bleed over, if this is a major problem.
1. make sure all connectors are tight
2. check the coax ends for cold solder joints
3. Check SWR’s (on a few occasions that was the problem)
4. If the coax looks old (cracks or you can see the shielding) replace it
5. Get filters: Low pass for CB. High pass for radio or TV

My for the record is 4 watts out of the radio, powers my amp to 225 watts. My frequency capability is 24.265 to 29.655. and my radio has Fm and CW(morris code)

1998 Isuzu Hombre

...bumpin up this old thread

does anyone know if cb amps are illegal to HAVE, or USE??? i've always wanted to research on those some more

YES.

Your CB can put out no more than 4 watts. There's no way to tell if you've modified your CB. Nor is there any way for you to get caught.

Drip, I got my Uniden PC78LTW tweaked and peaked at Bronco1 here in Phoenix, I know it can be done. I bought the unit from him, so he did it for nothing, but I don't think he charges more then $20 for it...if that. Bronco1 is on 32nd Street, just south of Bell Rd. I'm not sure what part of town your in, but any of us can give you directions.