Cobra 25LTD Classic tune up
 

I have an old (Aug 1991) 25 LTD Classic someone just gave me and it all
works except it`s just factory stock in everyway and doesn`t put out
worth a damn...I`ve been away from the game so long I`ve lost all my
notes on the various tricks to tune it up beyond swapping out the final
and driver..Clip this..change that...?...Maybe some of the old timers
who remember me and know I`m cool can lend a hand..Send me an e-mail if
you want to avoid the trolls who`ll turn this into an anti-keyclown
thread

Cobra 25LTD Classic tune up
 

Programbo wrote:
I have an old (Aug 1991) 25 LTD Classic someone just gave me and it all
works except it`s just factory stock in everyway and doesn`t put out
worth a damn...I`ve been away from the game so long I`ve lost all my
notes on the various tricks to tune it up beyond swapping out the final
and driver..Clip this..change that...?...Maybe some of the old timers
who remember me and know I`m cool can lend a hand..Send me an e-mail if
you want to avoid the trolls who`ll turn this into an anti-keyclown
thread


www.cbtricks.com

It's easier to leave it stock and run it into a small 2 pill amp.
They sound better that way.

Cobra 25LTD Classic tune up
 

They sound like crap stock..No modulation..With a 2 pill it would still
sound like crap just much louder :)

Cobra 25LTD Classic tune up
 

Are you crazy... that unit can be made to have tremendous modulation.

Professor
www.telstar-electronics.com

Cobra 25LTD Classic tune up
 

Are you crazy... that unit can be made to have tremendous modulation

Was that directed at me or Scotty?..They way Google displays the
posts it came out under mine so I`m not sure....I actually said that it
sounds like crap and has no modulation BEFORE you do anything to
it..I`m very aware it can be made quite loud and proud with the right
tricks :)

Cobra 25LTD Classic tune up
 

Programbo wrote:
They sound like crap stock..No modulation..With a 2 pill it would still
sound like crap just much louder :)

OK. I've got one on the shelf. I don't use AM only radios.
I know it works. I tried it once.

Anybody make an offer for it. Shipping would be actual postage from 212..

I should clean up this Uniden PC76XL and get that off my shelf, too.
Also a TRC-422 and a TRC-422A just sits and sits.

I'm not sure if I should sell the Regency Range Gain, Lafayette LMS-40,
Midland 76-858, and forget about my 2950.

I spent good money on the LMS-40 to get it repaired because some dork
had tried to put extra channels in it and had really butchered it.
I'd have to sell that one for at least $100. It's in good shape externally.

I also have a lightning struck 148GTL. The owner said it's DOA.
I'm not going to bother testing it. His A99 was toothpicks in the yard!

DONTSPAMME is every other letter in my email addy. Remove that to reply.
Serious inquiries only. Leave a phone number in the email for call back
and give a time referenced to a timezone to call on my dime.

Cobra 25LTD Classic tune up
 

Hello All:

I am hearing that many guys are addeding in another modulation IC, and
Modulation transformer to double the audio power, allowing a higher
carrier power to be 100% modulated.

Jay in the Mojave


Professor wrote:
Are you crazy... that unit can be made to have tremendous modulation.

Professor
www.telstar-electronics.com

Cobra 25LTD Classic tune up
 

On Sun, 19 Feb 2006 15:40:53 -0800, Jay in the Mojave
wrote:

+Hello All:
+
+I am hearing that many guys are addeding in another modulation IC, and
+Modulation transformer to double the audio power, allowing a higher
+carrier power to be 100% modulated.
+
+Jay in the Mojave

******
The carrier in Double Sideband Full Carrier Amplitude Modulation
should remain constant during modulation. If not, then you have a far
greater problem.

james

Cobra 25LTD Classic tune up
 

james wrote:

On Sun, 19 Feb 2006 15:40:53 -0800, Jay in the Mojave
wrote:


+Hello All:
+
+I am hearing that many guys are addeding in another modulation IC, and
+Modulation transformer to double the audio power, allowing a higher
+carrier power to be 100% modulated.
+
+Jay in the Mojave


******
The carrier in Double Sideband Full Carrier Amplitude Modulation
should remain constant during modulation. If not, then you have a far
greater problem.

james

Hello James:

No thats not how AM works. The Modulation increases and decreses the
amptitude during Modulation. Thats how double sidband full modulation
works. Look in a old ARRL Book.


Jay in the Mojave

Cobra 25LTD Classic tune up
 

******
The carrier in Double Sideband Full Carrier Amplitude Modulation
should remain constant during modulation. If not, then you have a far
greater problem.
james


Hello James:

No thats not how AM works. The Modulation increases and decreses the
amptitude during Modulation. Thats how double sidband full modulation
works. Look in a old ARRL Book.


Jay in the Mojave

Jay, I respectfully disagree.

An AM carrier doesn't change, just sidebands are added in the mixing (modulation)
process, and the instantaneous voltage shown on an o-scope will be 4 times greater
then the carrier power itself. Since the audio added is 50% of the carrier, the
RMS power will be 150% of the unmodulated carrier. The peak to peak voltage is
greater. Put a 1000 Hz tone on a signal and look at it on spec-an.

(make sure to do this test with an unmodified radio, "swing kits" ruin proper AM)