OpenGD77

Everything is fine now, on my 3 GD77
I have no change with my BER, 0,3% as usually (Jumbospots simplex)

Luc

Merci

Unfortunately, I noticed the problem that when I try to choose the frequency of Tx broadcasting on the radio RD-5R so that the hotspot receives the PTT press, at some point everything hangs on the radio and no button responds. You just have to turn the radio off and on again and this is how the situation is repeated many times.

SO5AJG wrote: ↑

Mon May 04, 2020 9:27 am

Unfortunately, I noticed the problem that when I try to choose the frequency of Tx broadcasting on the radio RD-5R so that the hotspot receives the PTT press, at some point everything hangs on the radio and no button responds. You just have to turn the radio off and on again and this is how the situation is repeated many times.

I corrected the frequency offset on the RD-5R, which everyone reported was 1.5kHz.

You may need to use a really large offset to connect to your hotspot.

My RD-5R won't work with any of my hotspots even when using the official firmware.
The Tx signal from the RD-5R is quite dirty as the same PA is used for both VHF and UHF, with just a switchable filter near the antenna.

IMHO. The RD-5R is a very inferior radio to the GD-77 or even to the DM-1801

Even after the reset, the radio freezes and reacts to nothing, which was not in the software from 30.04.

Hi,

SO5AJG wrote: ↑

Mon May 04, 2020 12:11 pm

Even after the reset, the radio freezes and reacts to nothing, which was not in the software from 30.04.

What is the RX/TX frequency offset on your RD-5R, and what power output have you selected ?


Cheers.
---
Daniel

Practically, as soon as I try to set the next Tx frequencies every + - 100 Hz, nothing comes out of it, because as soon as I press PTT, the radio freezes and nothing can be done but turning off the radio. Set power 250 or 500mW. I didn't have such problems with the software from 30.04
The radio is receiving correctly only can not broadcast.

Installed all three versions on radios here.

On the RD-5R Baofeng I initially had choppy audio from my MMDVMHat Duplex JumboSpot hotspot. This may relate to one user on the talkgroup.

On transmit I had about 1.9% BER into a GD77 hotspot.

Update 5/6: Further testing, the RD-5R is definitely on frequency on this release. I just got through checking the radio on my Agilent/Keysight VSA transmitter tester.

My RD-5R has both Chinese and US serial numbers on two stickers. The first is "RD5R*A13xx" where "xx" is the last two numeric digits. The second sticker toward the bottom of the radio has "S/N:US20136262xx"

Marc

Roger, can you explain to me why this happens, that with any software change, there is no problem with the reception of the signal from the hotspot, but usually there is a problem with sending to the hotspot. Is the receiver in the hotspot very narrowband and hence the need to adjust the offset on the rx hotspot or tx on the radio. However, after firmware changes, communication with the inverters is seamless. It is always difficult to set the communication in the direction from the Tx radio to the Rx hotspot, because the reverse can always be heard very well and it does not require any settings.

This may relate to the implementation of "Automatic Frequency Control" which is used to dynamically shift the center frequency of a receiver to the correct place for 4FSK / TDMA reception.

Most MMDVM Hat style radio interfaces (like the one used in the JumboSpot and by others) don't implement the AFC feature. This is why RXOffset is used to shift a hotspot to try and match the radio(s) used with it. The radio chip is the software defined ADF7021, and it does have an AFC feature available, but not implemented on the boards controlled by the STM32 / Arduino processor.

The handheld radios generally have AFC operating on their Receive side. The use of a GD77 as a hotspot for DMR operation (only) gets the benefit of AFC on it's receive side.

I'm not completely clear on why the JumboSpot doesn't implement AFC, but it could well be that the processor chip is completely occupied dealing with DMR protocol at higher levels. Someone more familiar with the code can comment on that.