Effect of Increasing Carrier/2010 Cobra 29LTD

[jimbowilly]

Hi,

If I add a 30pF to 68pF ceramic disc capacitor (rated at no less than 50V) in parallel with the 220pF capacitor at C62 on my 2010 Cobra 29 LTD Classic to increase the carrier.
How will increasing the carrier effect my radio’s performance?
If I increase the carrier, am I increasing my dead key?
What benefits would there be in performing this modification without installing the RFX75?

Jim W.

http://www.cbtricks.com/miscellaneo.../graphics/rfx75_cobra_29_carrier_increase.pdf

 

[psycho]

Instead of the RFX75 just buy a 100 watt amp and you'll be way better off.

 

[Moleculo]

Increasing the carrier means the same as increasing the "dead key". Depending on how your radio is tuned, it could affect the audio quality as you will be affecting the overall peak to carrier ratio. A good rule of thumb is that you want a 4:1 peak to carrier ratio...if it's less than that, it won't sound "right". If it's more than that, it might sound LOUD but it might also be distorted. It's difficult to say what the effect of increasing the carrier on your radio will be without seeing how it is currently tuned.

 

[kd-5-bgt]

I agree,get a good solid 100 watt kicker and throw the RFX75 in the scrap heap

 

[hotrod]

the cobra 2010 is a base ,with ssb i think. id buy a texas star amp
for the cobra 29 id buy an x force amp 1x4
as for peaking radios i wouldnt try increasing carrier. id actually
try to lower carrier to 1 or 2 watts dk then increase the ;amc;
or modulation control to full.when done should swing around
8-10 watts with stock final.

 

[Moleculo]

for the cobra 29 id buy an x force amp 1x4

I'm assuming that xforce 1x4 has something like a SD1446 driving 4 2SC2879s. For a regular CB like a 29 with a regular 4 watt carrier, I don't think I would use an amp with a driver transistor. But that's just me...

 

[loosecannon]

im curious to know if the people who dont like the RFX75 are speaking from personal bad experiences, or just dont like the idea in the first place.

the reason i ask is because i have been installing quite a few of these lately for people. (about 6 in the last two months. thats a lot for me LOL)

i have installed them in 29LTD classics, 29LTD army editions, and 29LTD black chrome, and all had very similar positive results.

about a 15 watt deadkey swinging about 75-85 watts PEP.

yes, its a bit over the 4:1 ratio, but not by much, and after all these are CB radios for CB radio operators who dont care if the scope image is perfect or not, they just care that the radio sounds loud and clear.

every one of them that i have done sounded great after the installation.

yes, the RFX unit can get hot on a long winded keydown, but so do RM italy amps and stinger boards, which are the only things i know of that are even in the same ballpark price wise.

if someone were to buy a 1 pill amp, they would have to feed it with about 1 watt, which would produce a very similar deadkey to what the RFX does.

so whats the beef? i dont want to start a fight and i dont work for magnum, i just want to know if there is something that i am missing.

34.00 plus a few bucks shipping is a pretty good dollar per watt value dontcha think?
LC

 

[loosecannon]

the cobra 2010 is a base ,with ssb i think. id buy a texas star amp
for the cobra 29 id buy an x force amp 1x4
as for peaking radios i wouldnt try increasing carrier. id actually
try to lower carrier to 1 or 2 watts dk then increase the ;amc;
or modulation control to full.when done should swing around
8-10 watts with stock final.

LOL, um hotrod, you might want to read the title again. :tongue:
he means that his 29LTD was made in 2010.
LC

 

[Moleculo]

I don't personally see a big problem with the RFX75 as long as they are durable. I think his original question was what would the benefits be to increasing the carrier without installing something like an RFX75.

 

[loosecannon]

good point about the durability mol'. guess we'll just have to wait and see.

lets make sure we answer the OP's questions.

yes, increasing your carrier means increasing your deadkey.

no, it will not be worth it. increasing your deadkey by this amount will not be noticeable at all on the receiving end.

you do not need to do this mod.
LC

 

[dxing440]

From my experience (current) my RFX75 is on a cobra 29 lxle, and it has been a headache! I DEFINATLY WOULD NOT RECOMMEND ONE! Buy an amp. Wish i had.

 

[hotrod]

I'm assuming that xforce 1x4 has something like a SD1446 driving 4 2SC2879s. For a regular CB like a 29 with a regular 4 watt carrier, I don't think I would use an amp with a driver transistor. But that's just me...

maybe i should put 2x4 not 1x4.only cause a stock cb wouldnt
drive a 4x2879.it would also matchup to a 2x2290 amp also or
2x1446.in this case only i would use a amp with a driver.
i normally dont though.

 

[W5LZ]

4 watts should drive 4 2879's just fine.
- 'Doc