AF does not work properly

wybitny2

I'm ashamed to admit it, but the best performing AF is the Mediatek Helio P65 on the Junsun V1 radio. Is it possible to improve AF in Europe to search for alternative stations? Navradio AF works great, you can't ask the developer how to fix it. Generally, the problem is that Af searches for alternative frequencies, but has a problem returning to the previous one. Or the opposite happens - it does not search for an alternative station. Radio reception often deteriorates when driving with AF on. It is not as stable as in the Mediatek Helio P65 processor - every time it looks for alternative stations, it hits the alternative station perfectly. I know that radio FM is becoming a thing of the past, but it will continue to work in Europe for a long time.

jamar

I second this, the RDS AF handling is not ideal right now. For me, I have to say, it's somewhat working, but only partially, with some glitches. I don't know whether the AF search function is done by Dudu or is handled by MCU, so it's developed by FYT, but in that case I hope at least Dudu can ask them to do some fixes.

From my experience over time it seems like the AF table includes wrong frequencies, from other stations. It seems that when swiching preset or tuning to other station the AF table retains frequencies from previous stations and then, when signal goes low, the AF function tries to tune to that wrong frequencies. This happens to me really often.
Correct behaviour should be that when tuning to another frequency/station, the AF table should be allways cleared and newly read from RDS data from currently tuned station. Then, when the signal drops below specified value (would be nice if that value could be adjusted by user in settings), start scanning through those frequencies in the AF table, tune to those with better signal and check for the station PI code from RDS and stay on than frequency only if the PI code is the same with currently listened station. If the PI code cannot be read from RDS, its maybe weak frequency or just some interference, then let's try another ones from list. If the PI code is different, then the checked frequency belongs to another station and then remove it from current AF list and check another ones.
It seems that when the checking for AF starts and there is some frequency where the signal seems to be better, but it's not correct station broadcasting (mainly stronger interferrence), AF routine tries to repeatedly tune to that frequency and does not move to another ones, even though I know there's better and working frequency in AF list (and I have to tune manually to that one). So as I wrote in previous point, when the AF function tries to check a frequency with seemingly better signal, but cannot obtain PI code from RDS, it should move on and try another ones from AF list.

As wybitny2 said, FM radio and RDS is really widely used in Europe and here in Czechia it will be used for at least another 10 years. So having it working correctly would be really appreciated. And I mean also other RDS function, for example TP (Traffic Program / Announcement), which is not working at all (even though on MTCD units it's working correctly, on Topway units also with some glitches), and I'm not mentioning EON, Radiotext+,...

RDS is really really old standard and it's a bit shame that a 30 years old simple Pioneer car radio I've used before could handle those functions way beter than this modern Android head unit loaded with functions... Yeah, I know, RDS is not used in China, so it's a bit difficult for developers to implement its functions correctly, but still...

So, pretty please, could you at least try to look on this and make some fixes? I can help with testing, if you'd like.
Thanks ;-)

VladOst

jamar
Добавлю, что при достижении на работающей частоте критического минимума уровня сигала (триггер для перехода на AF), нужно отсортировать список AF по силе сигнала (от лучшего к меньшему), и затем начинать сравнивать на них PI. Т.к. в зоне может оказаться пересечение нескольких частот одной станции, и не всегда сильнейшая будет в начале списка AF передающихся от станции.

wwest2

The developers are testing this currently since it's a critical problem.

jamar

wwest2
Really? I didn't know they're already working on this, that's a good news! Thanks for the info.

jamar

VladOst
You're right. The 7708 chip should be able to tune frequencies fast enough to scan for signal strenght with barely noticeable dropouts. And I guess it's maybe already done this way, but as I said, sometimes wrong frequencies appears on AF list from previously listened station. And some stations broadcasts AF list of their whole network, so there is possibility, that some frequency in the AF table might be in use by another station in particular area. That's why the check for correct PI is really importat and if it differs from PI of currently listened station, don't check that frequency again and try another one.
Today I was driving from my client between two cities, listened to some station and when the signal drops under level where AF kicks in, it starts trying a frequency with stronger signal, but from completely different station. And it kept trying it for at least minutes, cycling between station I was listening to and the different station within 1 second interval, forcing me to switch to another station, because it was sooo annoying ;-)