Serg.Ultra писал(а): ↑01 апр 2026, 22:38
Спасибо за схему. Однако она только добавила непоняток. Если следовать схеме , то микросхема Buloti - это перемаркированая NE602. Тогда совершенно непонятно её включение здесь в плане развода дорожек на плате.....
Сложно сказать, что именно BULOTI c Ultra там сделала. Я посмотрел на свои ATS25 Pro +AIR. Там стоят SA612A и Si5351. Схема подключения SA612A соответствует схеме: сигнал поступает на ввод 1, питание — на 8. 2 через конденсатор к земле. 3 на землю. Выход здесь 5, но согласно даташиту может быть и 4. Сигнал от Si5351 поступает либо на 6, либо на 7, это сложно понять. Я не изучал вопрос подключения Si5351, в принципе, онa работает. Кстати, этот ATS25 тоже от BULOTI. Для VHF (145 mhz)/Air — деньги практически выброшены на ветер, c Quansheng K5 Приём значительно лучше со штатной антенной.
Коротковолновый, FM и MW диапазоны работают отлично.
Выдалось немного времени, решил заменить Булоти на SА. Это просто: сдул микросхему и конд С65. Конденсатор пригодится под ногу 2, номинал самый тот. У SА перед запаиванием поднимаем ноги 2, 5, 7. Запаиваем микросхему слегка наискосок, чтоб нога 6 микр попадала между дорожек 5-6 на плате, а нога 8 между дорожек 7-8. Под поднятую ногу 2 припаиваем бывший С65 столбиком.
Только это всё-равно не помогло восстановить Авиа. Ну да ладно, пока отложу эту возню, не самое важное дело.
У меня обратная проблема как вернуть английский язык. Подскажите пожалуйста. На AIR очень высокий уровень собственных шумов. Буду разбираться но позже. Пока надо понять источни к помех с интервалом 65 - 66 килогец на всех диапазонах! Очень портит приём. В железе пока не нашёл , очень похоже на прогамный глюк (?). Не судите строго мои предположения, железо понимаю, опыта программирования нет.
Concerning the Ultra model radio on the VHF down-converter and the alleged issues when receiving signals on Air Band and 2 meter bands (excessive noise, hiding signals).
The mysterious BULOTI 001 Mixer chip used in the Ultra radio is not compatible with the common SA612A used in the other ATS25 versions.
It is however compatible with the original HP IAM-81008 5GHz active double balanced mixer/IF amplifier, accordingly to the information supplied by Andrei Petrov in their You Tube channel.
I am looking to my Ultra radio and analyzing the circuit.
A LSt / BGA2817 (U17) is used as VHF LNA in the RF front-end, feeding the VHF signal to the BULOTI 001 / IAM-81008 Mixer.
This is by the book implementation, as described in the HP IAM-81008 application notes, to compensate for the internal noise of the Mixer.
As Andrei explained, there is an design error in the Ultra VHF LNA circuit - The BGA2817 is being operated at 5VDC, well above its maximum operating limit of 3.8V. So there is the need to modify the circuit and take the 3.3VDC line to power the BGA2817.
As Andrei found out, this modification alone will not fix the VHF reception issues.
He installed a 10.7 IF filter at the output of the Mixer with no improvements - This solution seems to be in use on the Pro+ Air model.
He tried a passive mixer, also no improvements.
So, currently we do not have a solution to this VHF issue.
2. 65kHz cyclic RF noise across all AM bands.
This issue affects all radio bands, in particular the lower bands like MW, 120m, 90m, and so on.
At repetitive 65kHz cyclic intervals, there are peaks of RF noise that hide any radio signals at those points in the spectrum.
To see the issue, do a scan - The noise spikes at around every 65kHz intervals.
Andrei discovered that this interference was eliminated by removing C54 that supplies Clock signal from the Si5351A PLL Synthesizer at pin 9 (CLK1) to the Si4732-A10 AM/FM DSP Tuner at pin 13 (RCLK).
What I see in the circuit used in the Ultra:
The Si4732-A10 chip is wired to use two independent clock sources at the same time!
- One clock source is the common analogue setup where a 32.768kHz crystal is wired between pins 2 (DCLK) and 13 (RCLK).
- The other clock source, as seen above, is coming from the Si5351 chip and it is connected to the pin 13 of the Si4732 in absolute parallel fashion with the crystal oscillator.
There is no switching device (mechanical or solid state) to select what clock source should be used.
Moreover, if a external stable clock source is being used in the Ultra to generate two clock sources, one for the Si4732 and another for the VHF Mixer, why is the Ultra using the additional redundant 32.768kHz crystal?
This does not make sense, unless the original idea was that the crystal would be use for all the RF bands except for the VHF band.
If so, then the Firmware would need to take care of this scenario and configure the Si4732 and Si5351 chips to make sure that only one clock source would be active at a time for the Si4732.
So, what Andrei did was to eliminate one of the two clock sources, in this case he removed the Si5351 32.768 clock signal, leaving the crystal as the single 32.768kHz clock source for all bands including VHF.
My hypothesis:
The two conflicting 32.768kHz clock sources are creating this 65kHz RF noise artifact.
Instead of removing the Si5351 clock source, I would remove the 32.768kHz crystal device, as using a more stable clock source and also synchronized clock sources for the Si4732 and VHF Mixer are preferable.
My question to the Firmware developers:
I know that both the Si4732 and Si5351 chips need to be configured for clock source setup.
Please let us know how are the two clock sources being configured for each scenario - When VHF down-converter is in use and when it is not.
jebem писал(а): ↑Вчера, 03:01
My question to the Firmware developers:
I know that both the Si4732 and Si5351 chips need to be configured for clock source setup.
Please let us know how are the two clock sources being configured for each scenario - When VHF down-converter is in use and when it is not.
In the case of ATS25ULTRA, the only way to fix it is by removing elements from the printed circuit board. Configuring the si473x is independent of the generator being used.
