Experimental Baofeng RD-5R version

VK3KYY
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Re: Experimental Baofeng RD-5R version

Post by VK3KYY » Fri May 22, 2020 5:14 am

I suspect that this radio suffers too much from both RF injection and also to internal voltage regulation problems, which may ultimately mean it can't work as a hotspot without internally modifying the radio to fix these hardware design problems

We've already noticed that during DMR Tx that the display backlight and also the LEDs behind the keypad dim when the radio transmits each 30mS DMR pulse. This is regardless of the power level, but its more noticeable on higher power settings.

The internal voltage instability could possibly cause the CPU (MCU) to be unable to accurately read the voltage on the USB signals.

DL1DBY
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Re: Experimental Baofeng RD-5R version

Post by DL1DBY » Fri May 22, 2020 7:03 am

VK3KYY wrote:
Fri May 22, 2020 5:14 am
I suspect that this radio suffers too much from both RF injection and also to internal voltage regulation problems, which may ultimately mean it can't work as a hotspot without internally modifying the radio to fix these hardware design problems

We've already noticed that during DMR Tx that the display backlight and also the LEDs behind the keypad dim when the radio transmits each 30mS DMR pulse. This is regardless of the power level, but its more noticeable on higher power settings.

The internal voltage instability could possibly cause the CPU (MCU) to be unable to accurately read the voltage on the USB signals.
I have three RD-5R. On one one of them the voltage regulation is so bad that it resets itself every time the audio volume is above a certain level with extreme dimming of the screen illumination. If I switch on this one unit with audio volume set to maximum I can create a sort of "boot loop" because of the morse code start-up jingle of the firmware. Kinda extreme.

But all of them can now access the hotspot with the new firmware version with low BER (<0.3%), BTW.

tnx & vy 73
Dieter DL1DBY

VK3KYY
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Re: Experimental Baofeng RD-5R version

Post by VK3KYY » Fri May 22, 2020 10:53 am

DL1DBY wrote:
Fri May 22, 2020 7:03 am

I have three RD-5R. On one one of them the voltage regulation is so bad that it resets itself every time the audio volume is above a certain level with extreme dimming of the screen illumination. If I switch on this one unit with audio volume set to maximum I can create a sort of "boot loop" because of the morse code start-up jingle of the firmware. Kinda extreme.

But all of them can now access the hotspot with the new firmware version with low BER (<0.3%), BTW.

tnx & vy 73
Dieter DL1DBY
Hi Dieter

OK.

Thats good to know.

DL1DBY
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Re: Experimental Baofeng RD-5R version

Post by DL1DBY » Fri May 22, 2020 7:13 pm

CORRECTION: I found that one of my three RD-5R,which performed well with the stock firmware, now has high BER witrh my hotspots (3 - 5%) and sometimes fails to open the hotspot. This is with the "calibration" setting in "Menu" on or off.

I have the impression that it's worse with a duplex hotspot on 439/430 Mhz than with a simplex hotspot on 433 Mhz. But maybe I am wrong with this.

The other two units work well with hotspots.

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Re: Experimental Baofeng RD-5R version

Post by VK3KYY » Thu Jun 04, 2020 9:06 pm

DL1DBY wrote:
Fri May 22, 2020 7:13 pm
CORRECTION: I found that one of my three RD-5R,which performed well with the stock firmware, now has high BER witrh my hotspots (3 - 5%) and sometimes fails to open the hotspot. This is with the "calibration" setting in "Menu" on or off.

I have the impression that it's worse with a duplex hotspot on 439/430 Mhz than with a simplex hotspot on 433 Mhz. But maybe I am wrong with this.

The other two units work well with hotspots.
You could look at the calibration data for each radio, and use a frequency counter or a SFR as a reference to adjust all radios to transmit on the same frequency.

DL1DBY
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Re: Experimental Baofeng RD-5R version

Post by DL1DBY » Fri Jun 05, 2020 11:16 am

You could look at the calibration data for each radio, and use a frequency counter or a SFR as a reference to adjust all radios to transmit on the same frequency.
Would a frequency counter with 1 kHz resolution be good enough for this? This is all I currently have that is DMR capable.
Last edited by DL1DBY on Fri Jun 05, 2020 11:37 am, edited 1 time in total.

VK3KYY
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Re: Experimental Baofeng RD-5R version

Post by VK3KYY » Fri Jun 05, 2020 11:21 am

DL1DBY wrote:
Fri Jun 05, 2020 11:16 am
You could look at the calibration data for each radio, and use a frequency counter or a SDR as a reference to adjust all radios to transmit on the same frequency.
Would a frequency counter with 1 kHz resolution be good enough for this? This is all I currently have that is DMR capable.
I think the resolution needs to be more accurate. My counter is also only accurate to 1kHz, so I used my SDR dongle to compare the central frequencies when transmitting on FM, of my various radios, and I adjusted the ones which did not work so well with my hotspot, to the same frequency just by looking at the SDR spectral plot.

Unfortunately my DM-1801 will still only work with my simplex hotspot, even though I have calibrated the frequency to be the same as my other radios :-(

DL1DBY
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Re: Experimental Baofeng RD-5R version

Post by DL1DBY » Fri Jun 05, 2020 1:02 pm

I'll look into it and experiment. I have an old Radio shack counter (analogue only) which can detect the frequency of my simplex and duplex hotspots transmitting, but strangely none of my DMR radios of different brands in DMR mode.

Concerning my three RD-5R, these were the calib. values:

1. Very low BER: DMR Tx 4FSK 405Mhz-475 Mhz: 88 - 70, Ref. Osc. Tuning: 1014
2. high BER: DMR Tx 4FSK 405 Mhz - 475 Mhz: 81 - 64, Ref. Osc. Tuning: 969
3. high BER: DMR Tx 4FSK 405 Mhz - 475 Mhz: 78 - 62, Ref. Osc. Tuning: 969

I have changed Ref. Osc. Tuning on one of the bad units from 969 to 983. In analogue mode I was 500 Hz off and with this change I am spot-on, according to my freq. counter. However, the BER is still high, even higher after the change on 433 and 438 Mhz simplex and duplex hotspots, up to 4.0%.

By changing DMR Tx 4FSK for 425, 435 and 445 Mhz I was then able to get the BER down from 3.5% down to 2.0%. I was unable to reach ~0.1% which other radios, including one RD-5R, achieve. With the (otherwise crappy) stock firmware I had an BER of about 0.3%.

Are there other settings I could try?

HB3XPL
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Re: Experimental Baofeng RD-5R version

Post by HB3XPL » Sat Jun 06, 2020 10:27 am

Hello, i got a DM-5R Plus, when i install the firmware via firmware loader it asks me STABLE or UNSTABLE version.

If i chose stable it works but i have to set my MMDVM spot to a +950 offset and of course i can no longer use other radios.

If i chose UNSTABLE radio boots with an error " CAL DATA ERROR "

did i miss something ??

Thanks to all

VK3KYY
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Re: Experimental Baofeng RD-5R version

Post by VK3KYY » Sat Jun 06, 2020 11:13 am

There is something wrong with your calibration data, it doesn't have the normal signature bytes

Zip your Flash memory backup and post it here, so I can look at the calibation data signature

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