Reduce low power level

[AsciiWolf]

If possible via software, please consider reducing the "L" power level to something more reasonable. Currently, it is over 2.7 W for L power on 2m and over 2.4 W on 70cm. See this video.

[egzumer]

Use build option for power reduction

[ErikS-web]

Nice Table of measurements at the end of the film

p.s. Subject POWER also mentioned in Reduce power #52

[gartnl]

egzumer Did you, or someone else, ever measure the output with the reduced option on?

[gartnl]

Nice Table of measurements at the end of the film

Only one problem: look at the 27 MHz test at the end. The powermeter measures total power, including spurious and harmonics. So there is no way to be sure ( and I doubt it ) that the measured power is transmitted on the correct frequency. Only way to really see what is going on is a spectrum analyzer.

[egzumer]

I've got only this:

measurement data before firmware: H =4.5 , M=3 w ,L=1.2 data after firmware : H=4.5 w , M <1 w, L < 0.5w . The measured power in low mode is about 200 MWt, the switch device shows only a slight presence of transmission. Thank you so much for your help!

That is what he provided and I didn't want to push him, but it would be nice if someone could do some tests. I don't know what are the differences between different units. How good the factory calibrations is. What are the different values across spectrum, etc. I don't have power meter and don't have experience with this topic that is why I didn't want to touch it.

Some other measurments: https://github.com/ludwich66/Quansheng_UV-K5_Wiki/wiki/Measurements

The Qunsheng calibration itself contains 3 calibration points for beginning, middle and end for each of the bands. I will also add calibration editing to chirp driver.

[gartnl]

https://github.com/ludwich66/Quansheng_UV-K5_Wiki/wiki/Measurements

That is real good info! And, again, it shows that the HT should not be used outside of the design. I'm tempted to get myself an SA for Christmas just to see ...

[Hunterfnet]

The stock V.26 version is much old for compare and have bad performance , better try with a new online customs firmwares , the official that receives with the walkie or new stock versions for compare with the egzumer version and flash with k5prog and do not use the old UVMOD ver V.26 for reflash . This comparison says only that the old V26 firmware is obsolete out of date

[Hunterfnet]

For AsciiWolf The only way for reduce the power with egzumer firmware for now is transmit with N Narrow mode and L together almost on real distances (tested) and working . On others firmwares you can do others things and/or chose the ultra Narrow option N- that here is not the case.

[ErikS-web]

He uses version 1.26 and not 1.27, on which all custom firmware is based. But I'm not sure if that is an issue. Looks on display testing is happening at 145.475 and 433.575

I measured at 145.0000 with upper VFO. Center of the 2 meter band. With firmware 0.20.1

With a powermeter that works up to 150 Mhz (CN620A). Cannot measure the 70 cm.

[mentanah]

... and another fresh measurement from my dad recently with QS = egzumer v.19 UV 5R Plus from Quansheng with short and long (38cm) antenna from QS, Yaesu and Diamond and power on dummy load:

[maxibor]

An implementation of an even lower power setting can be found in this fork https://github.com/armel/uv-k5-firmware-custom

Here: https://github.com/armel/uv-k5-firmware-custom/blob/3e6c2959aeb5fc1b6c250766c8c5f95e601b7ad8/radio.c#L475

Apparently promising a low power setting as low as 20mW.

#ifdef ENABLE_FEAT_F4HWN
    // make low and mid even lower
    if (pInfo->OUTPUT_POWER == OUTPUT_POWER_LOW) {
        for(uint8_t p = 0; p < 3; p++ )
        {
            switch (gSetting_set_low) {
                case 0:
                    Txp[p] = (Txp[p] * 4) / 19;
                    break;
                case 1:
                    Txp[p] = (Txp[p] * 4) / 13;
                    break;
                case 2:
                    Txp[p] = (Txp[p] * 4) / 10;
                    break;
                case 3:
                    Txp[p] = (Txp[p] * 4) / 7;
                    break;
                case 4:
                    Txp[p] = (Txp[p] * 4) / 25;
                    break;
            }

        }
    }

Power estimates provided here https://github.com/armel/uv-k5-firmware-custom/blob/3e6c2959aeb5fc1b6c250766c8c5f95e601b7ad8/ui/menu.c#L352-L353

const char gSubMenu_SET_LOW[][7] =
    {
        "125mW",
        "250mW",
        "500mW",
        "1W",
        "< 20mW"
    };

Maybe the original author of this feature @armel can tell more about the real output power in the end ? It would be especially interesting to make the uv-k5 more PMR446 compliant (TXP < 0.5W)

[nosektomas2004]

Hello any chance this will ever be available? Set "custom" performances for LOW and MID? Personally, I would find it best if LOW = 0.5W MID = 1W HIGH = about 5W (maximum posible)...

[AsciiWolf]

Same here. Although in my case, the "sweet spot" would be 0.5W for LOW, 2W for MID and MAX (5W) for HIGH. :-)