• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
  • Click here to find out how to win free radios from Retevis!

COBRA 29 HAS A BODY INSTALLED A LINEAR AMPLIFIER BOARD

DTB Radio said:
anixon said:
thanks switch kit. just add the ekl 2030 &1230 with the 68capacitor and make adjustments.

If you want to get the max, it will be a bit more involved than that, but the CB Tricks mod will definitely get you a lot of extra modulation and power.

after all has been said and done on my bench , there is a lot more to it then what CBTricks has to say about it , (this was brought up in the tech section under mosfets) I found them more to act like a swing kit , low DK at 2 with just over 30 watts pep with audio off the scale )-: but you can bring the audio down but you better believe the 30 watt pep will go down with it. More work surely needs to be done as DTB and Bushwacker stated in the Tech section of the forum. And even after the extra work as was stated , you would only be looking at a 5 to 6 watt DK after all was said and done. These are nothing like the 1969 mods NOTHING ! and after finally getting around to do one myself , I wasn't impressed so far. For those with limited knowledge of these mosfets (like me) and one thinks he or she can just go out and buy one of these 10.00 mosfet kits for a Cobra 29 or 25 and your looking for a higher DK (which I personally think is what most folks are looking for when they get these) you will surely find out that's not the case and CBTricks does not go into futher detail on the instruction page , you will need to futher search the site for better results with these , that's if you can find them ? Cobra 29s and 25's will do 5 to 6 watts and swing anywhere between 20 and 25 watts pep by themselves , so for you's looking for more up to this point , save your money and time and just have your radio tuned and leave it at that. With power in perspective ......is it really worth it ?
 
Id go with a Mod V Plus or a Palomar 100 1x1446, 250 2x1446 cheap and does the job.

anixon said:
just wordering if anybody has installed a rm italy 203 LINEAR AMPLIFIER BOARD on a cobra 29.
i just wordering if it worth the money to install one in a cobra 29.
thanks
al
 
203 stinger

I have a 29 that i love. It dead keys at 1-2 watts and has a stinger board in a very small case bolted to the speaker holes.....the amp sticks out the bottom....i have a small computer fan blowing on the heat sink. I love having the 203 and it looks good in its little alum case painted black under my radio. I think the deal is get it out of the radio and put it in its own little box.
no problems at all......it is a better rig than the old stingers of old.

it has become my shop radio........works for me.....just a little alum and no problems.

I like the fet change too.....just wanted to try one of these.
galyn davis
 
I recently put one (ad-203) in a 29LTD and was immediately impressed with the amount of heat produced (I clipped the big resistor) and after weighing the pro's & cons I decided to solder the resistor back into place. I have no problems except that I cannot turn on the "soundtracker" unit as it squeals on transmit...the soundttracker unit is useless anyhow.
Everybody has told me how good the radio sounds with the board installed. I reduced the carrier from 4 watts to 2 watts and it swings as much as a 2078 will deliver.
After all is said and done I get a respectable 55 watts out my 29 with a stock mic even though I could clip the resistor and get ~175watt. Am real happy with the results, and will most likely put one in my two other 29's.
The newer boards have four mosfets (IRF 520?) instead of a single 1446.
I almost forgot to say that heat is not an issue with the big resistor in place...as I can get long winded and the radio never got hot.
 
well, let's see, a 2078 will put out anywhere from 18-25 watts PEP typically after a tune up.
you are putting out 55 watts PEP which means that you have doubled your power out.

this equates to a 1/2 an S unit increase in someone's receiver.

so if you were hitting them with an S-5 with your stock radio, you now hit them at S-5.5.

please don't bother telling me about all your friends who now hear you at S9 when they used to not be able to hear you. (i'm not saying they are liars or don't know what they are talking about; im just saying that there are other factors at play besides the power increase)
this is how the physics works, and i'm not guessing.

to increase your signal in someone's receiver by 1 S unit, you need to quadruple your power out. this is true for 1 watt and is also true for 10,000 watts.

you have to ask yourself whether or not the financial investment is worth the result.
LC
 
agreed 100% Tallman.
the RFX units needed to be tamed, and the biasing needed to be tweaked, but once done they worked well IMO.

I put one in an old 89GTL base station and it deadkeyed 15 watts and PEP was about 85 watts.
LC
 
  • Like
Reactions: Tallman

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Greg T has left the room.
  • @ BJ radionut:
    EVAN/Crawdad :love: ...runna pile-up on 6m SSB(y) W4AXW in the air
    +1
  • @ Crawdad:
    One of the few times my tiny station gets heard on 6m!:D
  • @ Galanary:
    anyone out here familiar with the Icom IC-7300 mods