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Message |
    
Tshelburne5002
New member
Username: Tshelburne5002
Post Number: 1
Registered: 3-2004
| | Posted on Tuesday, March 02, 2004 - 2:42 pm: | 
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I have a stock 29, I need it to key low and swing high to power a texas star 350. Need help |
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 237
Registered: 4-2002
| | Posted on Wednesday, March 03, 2004 - 7:13 pm: |
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I tried emailing you some mods for that radio and it came back as undeliverable. do you have another email? |
Bigbob
Senior Member
Username: Bigbob
Post Number: 1684
Registered: 12-2001
| | Posted on Thursday, March 04, 2004 - 6:12 am: |
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You can key high if you want, a friend had a stalker f9 dx jacked up to max and it was the best sounding rig driving a txstar350 I ever heard,he was running an 8 watt dead key,24 watt swing,and it sounded great and amp was just a little warm,but don't run it while idling the engine,it would put so much drag on the electrical system and suck the juice from the ignition and stall the motor.Bigbob |
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 242
Registered: 4-2002
| | Posted on Friday, March 05, 2004 - 10:24 pm: |
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I just tried sending that mod again on email tshelburne5002!!!!!
BoXCaR
 |
Tech808
Moderator
Username: Tech808
Post Number: 1694
Registered: 8-2002
| | Posted on Friday, March 05, 2004 - 10:47 pm: |
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Boxcar,
If all else fail's,
WHY not post the Mod's on the Copper Forum here so other Forum Member's can benifit if they are looking for Mod's also.
Lon
Tech808 |
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 244
Registered: 4-2002
| | Posted on Sunday, March 07, 2004 - 5:31 pm: |
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Tech808,
I apologize for not even thinking of that! Here it is!!
Modulation Increase For Cobra 25LTD & Cobra 29LTD
Parts Needed
1- 220uF(16 to 25 volt) electrolytic capacitor
1-100 ohm(¼ watt dead key) or a 200 ohm(½ watt dead key resistor
Note: The higher the value of resistor, the higher the dead key but I have a 100 ohm in mine and it’s nothing but full swing.
Assembly
Make sure your radio is peaked out.
Unsolder JP6(cobra 25’s) or JP36(cobra 29’s) near final.
In holes, solder the 220uF capacitor(negative side of cap faces final)
On the solder side of the board, solder the resistor across the 220uF capacitor.
You can use different resistor values to get the desire dead key.
I would advise soldering out the jumper just in case it doesn’t work right and you can just solder it back in with no problems to the radio. I have done this on 2 of my cobra radio’s and had excellent reports. You will have to get use to the dead key being low at around a ¼ or ½ watt, whichever you want but the modulation is almost so loud that you will have to watch the mic’s you utilize in these radio’s because I run an astatic M6B and I can’t turn it up too much or I slop over everyone’s t.v. in the neighborhood so it does get out. It’s also a MUST if you want to drive a linear because the low dead key saves your pills in the amp if you’re running a solid state amp.
-BoXCaR-
 |
Tech808
Moderator
Username: Tech808
Post Number: 1723
Registered: 8-2002
| | Posted on Monday, March 08, 2004 - 9:21 am: |
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NO PROBLEM,
WE have a LOT of Forum Member's out there who own the 29LTD and it will help them all.
Thank's
Lon
Tech808 |
Boxcar
Intermediate Member
Username: Boxcar
Post Number: 245
Registered: 4-2002
| | Posted on Monday, March 08, 2004 - 8:54 pm: |
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Yeah, it's probably one of the best in my opinion of mod's you can do to a mobile radio that will let you drive whatever you want and save on the pills or tubes. Take care!!
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Fusebreaker
New member
Username: Fusebreaker
Post Number: 3
Registered: 3-2004
| | Posted on Monday, May 03, 2004 - 2:35 am: |
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what about adjustable power on the rf gain knob is this good or bad? and also if im running a barefoot radio will i talk farther?
fusebreaker936 in da show me |
Spaz
New member
Username: Spaz
Post Number: 8
Registered: 6-2004
| | Posted on Friday, July 16, 2004 - 11:37 pm: |
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Boxcar, Won't a 470uf hold the charge a little longer? |
Tech548
Moderator
Username: Tech548
Post Number: 137
Registered: 5-2004
| | Posted on Saturday, July 17, 2004 - 1:36 am: |
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Spaz
You're confusing me. Why do you need it to hold a charge? The only time that it is in use is when the RF circuit is keyed.
Tech548 |
Spaz
New member
Username: Spaz
Post Number: 9
Registered: 6-2004
| | Posted on Sunday, July 18, 2004 - 10:16 pm: |
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I'm probley wrong but I understood the way the cap works is how much it holds. If staying keyed or talking for a long amount of time doesn't the 470 work better? |
Brewdirect
New member
Username: Brewdirect
Post Number: 1
Registered: 7-2004
| | Posted on Thursday, July 22, 2004 - 4:00 pm: |
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Best mod ever...do the super modulation modification...perfect for running an amp.
I used a 470uf35vdc capacitor and a 100 ohm resistor, gives me a 1 watt deadkey with 10+ watts of swing.
Want a variable deadkey...use a potentiometer too and you can turn your deadkey up to 4 watts and still swing high when not running the amp. |
Brewdirect
New member
Username: Brewdirect
Post Number: 2
Registered: 7-2004
| | Posted on Thursday, July 22, 2004 - 7:39 pm: |
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Thanks Tech, lots of great info here.
Just picked up a Magunum 257 last week and found the info here was very helpful. |
Northstar
Junior Member
Username: Northstar
Post Number: 36
Registered: 2-2002
| | Posted on Saturday, August 14, 2004 - 1:19 pm: |
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From reading the mods above. These are definitely things that are not the proper way of tuning up these radios. Anytime you change a component you have to change components around it to match the impedence of the circuit in the radio. |
Lasthighlander
New member
Username: Lasthighlander
Post Number: 5
Registered: 8-2004
| | Posted on Monday, August 23, 2004 - 7:50 pm: |
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I have heard guys say you have to change out the 29ltd to put in the 1969 final. What parts do you change out? |
Scannersam
New member
Username: Scannersam
Post Number: 3
Registered: 6-2002
| | Posted on Monday, August 23, 2004 - 11:06 pm: |
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Would like to add TALK BACK to my COBRA 29 CLASSIC. THANKS |
Bc910
Member
Username: Bc910
Post Number: 86
Registered: 7-2004
| | Posted on Tuesday, August 24, 2004 - 11:12 am: |
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For talk back on those radios, the easiest way I know of is to put a resistor from the negitive side of the PA jack to the negative side of the external speaker jack. You would be smart to put a pot in between, or a switch tho. That's the way I do it any way, there maybe other ways tho
Have fun
BC |
Brewdirect
Junior Member
Username: Brewdirect
Post Number: 32
Registered: 7-2004
| | Posted on Tuesday, August 24, 2004 - 3:38 pm: |
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Northstar,
The super modulation modification listed above with the Cap and resistor is a great modification. used it on many radios now with no ill effects. I never swap finals on radios as I think it is a waste of time if you are trying to get more power..in those cases I'd just get an amp.
But the super mod is a great modification, to anyone trying it have now fear...just make sure you put the neg side of the capacitor towards the final.  |
Guardian
Junior Member
Username: Guardian
Post Number: 37
Registered: 5-2004
| | Posted on Saturday, May 26, 2007 - 2:22 pm: |
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can a 29ltd st be funnied out with extra channels without a kit Doug |
Dx_freak
Junior Member
Username: Dx_freak
Post Number: 15
Registered: 2-2007
| | Posted on Monday, July 30, 2007 - 12:57 am: |
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I see this is a rather older post but it seems to be a good place to post this question rather than posting a new thread. I want to find out if volting the finals on radios as the cobra 25 and 29's are possible to achieve more out put? Anyone know anything about this? I have heard of it being done for key downs, but I kind of want to ask and find out here. Anyone have any input?
Richey
DX freak/Mad Dog/Puppet Master
CEF#885
I can only do the best I can with what I got.
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Dale
Senior Member
Username: Dale
Post Number: 1046
Registered: 12-2002
| | Posted on Monday, July 30, 2007 - 6:02 pm: |
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personally i think volting fiNALS IS a waste
of time for only a few watts.read these older
posts best mod for that radio is listed above
our posts.
dale/a.k.a.hotrod
cef426
cvc#64
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Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2598
Registered: 9-2004
| | Posted on Wednesday, August 01, 2007 - 12:11 am: |
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best mod for the 25/29 series of radios is the MOSFET final conversion.
these radios can swing to over 35 watts with this mod done.
my pc68xl deadkeys at 2 watts and swings to 32.
turn up the modulation pot and you're all done.
if deadkey is too high for your application after MOSFET mod, then the swing mod with the cap and resistor will have to be done.
experiment with the value of the resistor to achieve the deadkey you want.
swing will always be the max the radio will do.
if done right, they work great.
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Dx_freak
Junior Member
Username: Dx_freak
Post Number: 18
Registered: 2-2007
| | Posted on Wednesday, August 01, 2007 - 5:08 pm: |
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Does anyone have the Mosfit info for the 29's? What im doing is getting my galaxy out of my truck and putting a cobra 29 that can drive my, well lets say it this way. I want to have the good hard drive as the galaxy does, or as close as I can. Been lots of theft here and I dont want to be putting windows in my truck for and or nor do I want to replace my galaxy. An old crapy looking cb like the 29 will get passed up where as my galaxy wont. I know how to do the swing mod, Id love to be able to do the mosfit. Can anyone point me in the right direction?. Oh as for volting them. I got into my bk presision 12 amp power supply that USE to do only 13.8 volts, well I found were I could crank up my voltage in the power supply and have it doing upto 22 volts. It will vary 0 to 22 volts now ((SWEET)). I hit that 29 with 18.5 volts and got 40 watts out of it after I did the swing mod and folks I talk to 20 miles away thought I was talking on my voyage vr 9000 with the echo off. Its only a few watts, well actually it is doing 22 more watts at 18.5 volts, but anyway, it is fun too do and if I blow that 29 up, well there are 10 more or so on my shelf to put in its place not too mention the 25's and the unidens I have.. It is not a waist of time when all you have is time right. And 1 more thing, I have been volting that 29 at 18.5 volts now for 2 days. It is still doing 38-40 watts. WOW. It is the 1st time I have ever tryed volting things and if I can get a 29 to do 30 watts in my truck, that is fine. 1.5 dead key swinging 30 will do exactly as I need it to and as far as echo, all everyone does is complain about it anyway, so it wont be missed.
Richey
DX freak/Mad Dog/Puppet Master
CEF#885
I can only do the best I can with what I got.
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Unit199
Advanced Member
Username: Unit199
Post Number: 516
Registered: 8-2003
| | Posted on Wednesday, August 01, 2007 - 8:19 pm: |
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If you turned the voltage up and hit the 29 with 18.5 volts, I am very surprised that the radio did not go up in smoke. You were very lucky, because radios are not designed to take this kind of voltage. Usually 14 volts is all most radios will handle then you start blowing parts.
HARVE
UNIT199
CEF210
CVC18
KB0YVK
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Dale
Senior Member
Username: Dale
Post Number: 1054
Registered: 12-2002
| | Posted on Wednesday, August 01, 2007 - 9:06 pm: |
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yea thats definately hard on finals and other
componets.yea put more volts to it youll see
more watts but how long do ya think itsd gonna
last.a mosfet mod DONE PROPERLY will do that
and run cooler and lasdt longer.hmmm which sounds better now
dale/a.k.a.hotrod
cef426
cvc#64
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Dx_freak
Junior Member
Username: Dx_freak
Post Number: 19
Registered: 2-2007
| | Posted on Thursday, August 02, 2007 - 12:00 pm: |
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Well day 3 on this cobra. It is still taking the abuse of 18.5. Maybe this radio was built from and old recycled sherman tank??? I actually and suprised at it myself and very suprised that the smoke is still contained in the radio. Id still like to find out about the mosfit mod though. I actually need to do it soon. Tired of removing and reinstalling the radio everyday but this is the only way im keeping it.
Richey
DX freak/Mad Dog/Puppet Master
CEF#885
I can only do the best I can with what I got.
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Dale
Senior Member
Username: Dale
Post Number: 1060
Registered: 12-2002
| | Posted on Thursday, August 02, 2007 - 10:05 pm: |
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well ya really cant go wrong going with the
mosfet mod.i personally never done the mod. but
had a uniden pc 66 with it.if i remember right
it dk=2watts and pep=25-30 watts pep
dale/a.k.a.hotrod
cef426
cvc#64
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Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2600
Registered: 9-2004
| | Posted on Thursday, August 02, 2007 - 11:21 pm: |
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those mods are here on the forum.
not sure which section, but they are here.
try searching.
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Dx_freak
Junior Member
Username: Dx_freak
Post Number: 42
Registered: 2-2007
| | Posted on Thursday, October 11, 2007 - 10:02 pm: |
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I have been seeing the elk2030 mod with the companion parts but due to me getting a hand full of the irf520 finals to fix the washington I have, I now have extras. I purchessed a few extra to try some of these mods out. Id like to atleast see for myself what if any difference there will be. Only this is I do not know what to do as for these being the irf520 finals. Ive seen them as the same as the elk2030 and seen that they are not. Id say not they are not. I also am unsure if the companion parts needed for the 2030 are needed for the irf520 also. Anyone have any info for me? Also, if I do need the comanion parts, were can I get them besides coppers and or other online stores. They all want 10 bucks to send less then a pound containing 6 of the companion parts. Way to high on shipping, the shipping alone will make the companion parts cost as much as the 1969's and the 2312's. Can save $$$$ doing that.
Richey
DX freak/Mad Dog/Puppet Master
CEF#885
I can only do the best I can with what I got.
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Blacksmith
Junior Member
Username: Blacksmith
Post Number: 16
Registered: 2-2005
| | Posted on Sunday, December 02, 2007 - 11:57 am: |
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Tech 808, when performing the modulation mod do I need to readjust anything else?? |
Tech808
Moderator
Username: Tech808
Post Number: 14774
Registered: 8-2002
| | Posted on Sunday, December 02, 2007 - 12:30 pm: |
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Blacksmith,
I personally have never found any reason to do the Modulatuion mod to a Cobra 29 as it already will swing 100% modulation.
Just add a DM-452 hand mic and you will be all set and a lot less work.
Just my thought's,
Lon~Tech808
CEF#808~HAM#001
CVC#002
Tech808@copperelectronics.com
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Kc5rcv
New member
Username: Kc5rcv
Post Number: 1
Registered: 11-2007
| | Posted on Sunday, December 02, 2007 - 10:54 pm: |
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I installed a switch in my galaxy 2517 so it will transmit on 10 and 11 meter. This hopefully wont hurt the use of the radio? |
Blacksmith
Junior Member
Username: Blacksmith
Post Number: 17
Registered: 2-2005
| | Posted on Monday, December 03, 2007 - 4:29 pm: |
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OK I was talking about the mod to dead key a 1/2 watt and swing 6 or 7 watts by putting in the 220uf cap. Do I need to readjust anything else or just do the mod and call it good? |
Dynamiteman
New member
Username: Dynamiteman
Post Number: 3
Registered: 2-2009
| | Posted on Saturday, March 21, 2009 - 9:15 am: |
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Well i have done the cap & resister mod to 3 29's $ 1 25 and they work great & sound very good also added var. power to them. next i'm going to do the mosfet final conversion.
dynamiteman-433
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Vannmann
New member
Username: Vannmann
Post Number: 1
Registered: 1-2024
| | Posted on Tuesday, January 09, 2024 - 4:25 pm: |
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Why not use a 0-100ohm variable ohm resistor on the opposite side of the capacitor so you can adjust if needed for preferred deadkey? |
