RF power: how does it work?

EricZimmerman

i fully recognize i might just be a complete idiot here, but…

i have tried to figure this out with SmartSDR and aetherSDR to no avail.

I have a flex-8600, pgxl and tgxl. for digital mode, i really do not want to blast out mega wattage. it would be nice to be able to just set a global max power regardless of settings somewhere, but that doesnt seem to exist.

so my question is, how exactly does the slider work for rf power? is it TOTAL power available in the setup, ie 2000w with the pgxl in place, or is it 100w for the radio which then drives the pgxl?

if 5w from the radio ends up around 200, its dumb to have the slider be forced to operate in the 5% of the left side of the slider. if i set the radio to 5%, the FULL range of the slider should work so the power selection is smoother across the entire slider

the other thing is, how does DAX TX audio levels affect wattage? again, if i say "do not shoot more than **** watts from this radio" then that should be the hard cap and not a combination of 43 variables

any insight here?

What exactly is the process to use the pgxl and not end up blasting 600 watts out? i use mshv but the software shouldnt matter much.

KD0RC

Hi Eric, The RF Power slider shows percentage of full power capability of the radio. So for 6000 and 8000 series radios, 1 percent = 1 watt. For Aurora series radios, 1 percent = 5 watts. This is independent of any amplifiers that you have connected.

To limit the output of the radio, you can set Max Power on the TX tab of Radio Setup:

Note that if you set this to say, 50%, then the RF slider will move down to 50% and will not be adjustable higher until Max Power is set higher. In other words, the slider does not change scales to indicate percentage of Max Power, it keeps either 1% or 5% depending on your radio model.

EricZimmerman

that is just silly to me. how am i supposed to fine tune how the pgxl works when i am limited into the 5% of the slider?

whatever the max percentage is in the Max Power box should be spread across the entire slider, AND the actual power output as the slider moves around IMO.

ie the slider at full left = 0, the slider at max right, = Max power configured, slider in the middle = half of max power

furthermore, when i cap at 5w and try to tune, tgxl then complains about low RF power. can i stop the amp from going into standby when tuning?

Trucker

The power meter in SmartSDR reads power output in watts for the 6000 and 8000 radios and the 500 watt Aurora radios. The slider reflects it in watts for the 6000 and 8000 radios. With the Aurora radios it presents it as percentage. I just checked this to be sure. ( I have a 6600 and a Aurora AU-520M)

James

WD5GWY

Geoff AB6BT

Actually, they are both showing percentage…

Trucker

Maybe so,but with my external watt meter inline, it reads the same thing as the tool tip on the slider. But, then again, since the Slider is scaled 0 to 100. It can represent the output of a 100 watt radio and then be thought of as percentage for a 500 watt radio. Come to think of it, this actually makes more sense as scaling the Slider 0 to 500 would make accuracy setting the output more difficult and would require a bigger Slider to overcome that issue. So, making it a percentage representation solves two problems with one control. I just never realized that the slider was reflecting percentage in both use cases. Maybe a label added above the slider saying percentage of power output would eliminate any confusion.

James

WD5GWY

Geoff AB6BT

Yeah, there is certainly some confusion regarding the power slider, but I'm pretty sure I read in one of Flex's docs that it was percentage. Of course sometimes my recall isn't what it used to be…

Ken Wells

The Power Slider is calculated as a percentage of the power output of the radio. It just so happens that the Percentage of a 100 Watt radio also equals the Percentage……

In Transverter mode, however, the Power Slider controls the Percentage of the Max Power that is programmed in the Transverter Configuration. (for the power sent to the XVTA or XVTB Port)