how many watts for a amp

[dxing440]

Does anyone know which amp i could use, I`m looking at texas star or palomar. Don`t want to run extra batteries. But would consider (1) maybe!
Alt is 136 amp.

I have a 29lxle with a RFX75 @14.2v I`m seeing a variable dk of 0.5-4.5w and swing to 20-25w RMS on a dosy 4001
.
The tech i purchased it from say`s its dk is variable of 2w-11w and seeing 80-90w PEP on an a bird43. Which do i go by? PEP from a dummy load, or RMS on an actual mobile antenna?

 

[office888]

The RFX75 isn't as powerful as some people make it out to be. It has a pretty dirty output to it, so unless you can measure dB off a scope to be sure you're measuring off your actual audio wave, and not some gross peak, well then take all readings with a grain of salt.

40w-50w PEP is a more realistic representation of the RFX75.

 

[North Texas Mudduck]

if that is all you are seeing from your 29lxle with rfx kit then something is wrong
and you dont want to run a Texas star or palomar behind that radio

should look into a custom built 4pill amp with 2879s and call it a day

 

[RatsoW8]

The RFX75 isn't as powerful as some people make it out to be. It has a pretty dirty output to it, so unless you can measure dB off a scope to be sure you're measuring off your actual audio wave, and not some gross peak, well then take all readings with a grain of salt.

40w-50w PEP is a more realistic representation of the RFX75.

What he said ...the RFX75 is a scam. Over.

 

[mackmobile43]

The RFX75 isn't as powerful as some people make it out to be. It has a pretty dirty output to it, so unless you can measure dB off a scope to be sure you're measuring off your actual audio wave, and not some gross peak, well then take all readings with a grain of salt.

40w-50w PEP is a more realistic representation of the RFX75.

A guy I used to run with ask me to check his galaxy that has a rfx on it and I came up with the same numbers, 50 watts pep with the mic gain full right and me blue in the face loud in it.

 

[pro151]

Would the old saying of amp output not apply to the 75 as with any pill type amp?

"Whatever the builder claims, deduct 25% and you will have your true output"

This is of course based on not driving the snot out of the amp, but running it sensibly where it will last.

 

[dxing440]

Thx everyone for the advise. I definately am dissapointed all together with the radio. Could be the tech at Epoweramps.com. On further check of the radio, it DK`s 4w channel 1-25, 3w channels 26-30, and 2w on channels 31-40. BUT it still swings 25w, thats all with the engine running (14.2v).
Engine off (12v) off battery it`s DK dont even move the needle! (0.0w) But still it swings 15w.
I DO NOT RECOMMEND THE RFX75 TO ANY ONE, IT MAKES THE RADIO INCONSISTANT EVERY TIM EYOU KEY.
Im gonna try a local cb shop to try and fix it right.

 

[999]

You need to check that into a dummy load. Most likely the watts are changing due to the SWR change as you change frequency.

 

[dxing440]

Hey 999,
Thats what i dont understand. The numbers are higher on a dummyload at 1.0:1 swr. But its not being operated in the vehicle on a dummy load, the antenna has a swr of 1.3:1 on all 40 channels.

So it doesnt have a 10w DK as on the dummy load, it has a 4w@14.2 on an antenna, and a DK of 0.0w@12.0 on an antenna.
If i go by the Watts obtained from a dummy load, wouldn`t that under drive the amp?
Not disputing what you are saying, just trying to learn and understand!
THX

 

[999]

I think the 0 watts is due to the mod in the radio not having enough amps or volts for it to function properly.
Even though you are seeing the same SWR on all frequencies there is a difference. It has to be in the antenna system as to why you are seeing the changes in wattage.

On the dummy load is it the same on all channels? It should be.

 

[dxing440]

ok thx for the input, as long as it works, thats all that matters. Keep dxing!

 

[unit_399]

This is of course based on not driving the snot out of the amp, but running it sensibly where it will last.

You're right... but this isn't the cb way to do things.

 

[dxing440]

Hey guys, got the 29 lxle w/rfx75 fixed up! keys 1w-5w swings 25w (RMS),
and keys 3w-14w and swings 85w (PEP) Nice drive for a 4 pill, i think.