Copper Talk » Ask The Tech » Radio's Mobile » Cobra 29 nw wx st « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

615_ri
Junior Member
Username: 615_ri

Post Number: 41
Registered: 5-2006
Posted on Wednesday, May 09, 2007 - 8:46 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

i recently did the 40 watt high power mod found on here. im dead keying 3 and swinging to 10 with horrible modulation. anyone suggestions? btw i installed the erf 2030, and erf 1230 along with the 68 pf capacitor. i dont know why but this radio will not get loud or get anymore power.
Top of pagePrevious messageNext messageBottom of page Link to this message

Romstar
Intermediate Member
Username: Romstar

Post Number: 104
Registered: 3-2007


Posted on Thursday, May 10, 2007 - 4:43 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

It has to be retuned.

You need at least a multi-meter (I seriously recomend BOTH an analogue and a digital) and a frequency counter. Not a little display, but an actual counter.

Make sure you re-adjust the bias.

This is where a good tone/signal generator comes in very handy. If you know exactly what's going in, you can test for it coming out.

If you have a power mic, ditch it while you are adjusting the radio.

The 29 is a little funny, but the 25 seems to take to the upgrade with little problem.

Romstar
Top of pagePrevious messageNext messageBottom of page Link to this message

615_ri
Junior Member
Username: 615_ri

Post Number: 43
Registered: 5-2006
Posted on Thursday, May 10, 2007 - 5:54 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

can u tell me how
Top of pagePrevious messageNext messageBottom of page Link to this message

Brain_damage
Member
Username: Brain_damage

Post Number: 51
Registered: 4-2005
Posted on Wednesday, May 16, 2007 - 6:16 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

i had that mod done on a 29 and a 25,the 29 is very loud and clear.the 25 evry time i key up the 25 the needle bangs the other side of the meter,both of these radios are keepers
Top of pagePrevious messageNext messageBottom of page Link to this message

Romstar
Intermediate Member
Username: Romstar

Post Number: 106
Registered: 3-2007


Posted on Wednesday, May 16, 2007 - 9:49 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Brain Damage,

You need to adjust that meter to prevent it from breaking. There is too much going into it.

Romstar
Top of pagePrevious messageNext messageBottom of page Link to this message

Guardian
Junior Member
Username: Guardian

Post Number: 39
Registered: 5-2004
Posted on Thursday, June 07, 2007 - 10:51 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

can the pll be changed in the 29 ltd to a different one
Top of pagePrevious messageNext messageBottom of page Link to this message

Romstar
Intermediate Member
Username: Romstar

Post Number: 109
Registered: 3-2007


Posted on Friday, June 08, 2007 - 4:15 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Okay, first off I'll ask WHY you would want to do this.

Then I will go out on a limb and say yes you COULD change the PLL. How deep you get into this depends highly on how good you are at electronics.

Some chips are drop in replacements, others are not. In some radios there was a chip change to bring a radio into conformance with FCC rules, and you can take out the new chip, and put in the original it replaced.

In any case, if you use all the stock circuitry you will need a functionally identical chip, and you will need to tune it.

If on the other hand you use something entirely different, you are going to be making some SERIOUS modifications. You can even go so far as to design a new board that can be patched into the pin holes for the original PLL, but that requires some serious design work and tuning.

This normally isn't something you want to get into. As I said, there are some exceptions to this.

Romstar
Top of pagePrevious messageNext messageBottom of page Link to this message

Kid_vicious
Senior Member
Username: Kid_vicious

Post Number: 2551
Registered: 9-2004


Posted on Saturday, June 09, 2007 - 9:35 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

if the 29LTD in question uses the upd2824 chip, then yes, it can be replaced with a upd2816 chip to allow for freq. conversions.
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!

Add Your Message Here
Post:
Username: Posting Information:
This is a private posting area. Only registered users and moderators may post messages here.
Password:
Options: Enable HTML code in message
Automatically activate URLs in message
Action: