Доработки оригинальной схемы ATS25

[ikuclja2]

The scheme has an error, pins 1 and 4 on the BL1551B chip have been replaced.

[ulmann]

А можно для "чайника" более доходчивее с рисунками или фото показать как присобачить блютуз передатчик внутри приёмника.

[G8PTN]

The scheme has an error, pins 1 and 4 on the BL1551B chip have been replaced.

Hi,
Yes, I agree that the previous schematic shown looks incorrect.

From the layout information (Ref: https://github.com/IU4ALH/IU4ALH/tree/main/PCB's), the BL1551B switches appear to be connected as shown in the diagram below.

The RF switches appear to be connected correctly, but I have some doubt about the control circuit. See further notes below.

1. GPO1 and GPO2 signals.
Care needs to be taken when using GPO1 and GPO2, since these pins are sampled at power up to determine the bus mode for the control interface.
An extract from the datasheet is shown below.

Some hardware implementations (e.g. ATS25-AMP) also have external resistors on the GPO1 and GPO2 signals to ensure the correct levels are detected at start-up.
GPO1 10kΩ pull-up to 3V3.
GPO2 10kΩ pull-down to GND.

2. PNP transistor on GPO2
The proposed circuit may not work correctly since it may corrupt the startup value for GPO2 and there is no load resistor on the collector of the transistor.

The control state for selecting the mixer will be opposite to that shown on the diagram from Binns.

GPO2 = 0 = Mixer bypass.
GPO2 = 1 = Mixer enabled.

The logic thresholds for the BL1551B ENB input are TTL compatible, so it should be possible to drive it directly from GPO2 of the SI4732 (possible alternative).

73, Dave

[Darwin]

Good afternoon, my name is Darwin. It is a pleasure to belong to the forum.
I recently bought the ats25-amp and I have doubts about expanding the band with si5351.
The ats25-amp does not have the ne602, it has a 32,768 crystal.
If you could provide me with a diagram it would be of great help.
It would be a great help to be able to connect the board or follow instructions.
a cordial greeting.

[G8PTN]

Hi Darwin,
For the expanded frequency modification, both the SI5351, NE602 mixer circuit and associated RF switching would be required.

The on-board crystal is connected between SI4732 (GPO3 - Pin 2) and (RCLK - Pin 13).
When using the SI5351 for the frequency reference, the crystal would need to be removed and SI5351 (CLK0) connected to SI4732 (RCLK – Pin 13).

The mixer circuit with the NE602 uses SI5351 (CLK1) as shown in the generic circuit provided by Binns in the link below.
viewtopic.php?t=11&start=22

Relay or solid-state selection for the required RF paths is also required.
An example for solid-state switching is shown in the above link and there are other examples on the Facebook groups.
The selection is done using SI4732 GPO1 and GPO2 pins.
Unfortunately, these signals are already used on the ATS25-AMP for its own RF switching. I have covered this in the link below.
viewtopic.php?t=105&start=10

Also, for information, there is no 5V rail on the ATS25-AMP, so a boost regulator or charge pump would need to be added.

In summary, it would be possible to modify the ATS25-AMP for the expanded frequencies, but it is not so straight forward.
I expect there will be future releases of the ATS25 with the expanded frequency feature added.
I hope this has covered your questions.
73, Dave

[Darwin]

Hello G8ptn, thanks for the information provided. I thought it could be connected as shown in the image and to connect the JP2 using a manual switch. to expand the band.

[Spoiler]

У меня есть такой же модуль, как на картинке уважаемого Darwin (download/file.php?id=161&mode=view).
Если мне не нужно расширение диапазона, а нужны только стабильность и точность установки частоты, можно ли использовать схему из его же поста выше ⇈ без всякого микшера NE602? Дивайс ATS25 max-Decoder II

[G8PTN]

I have the same module as in the picture of the respected Darwin (download/file.php?id=161&mode=view).
If I don't need to extend the range, but only want stability and accuracy of frequency setting, can I use the circuit from his post above ⇈ without any NE602 mixer? Device ATS25 max-Decoder II

Hi,
Yes, if you only want the frequency stability feature, you do not need the NE602 mixer and its associated circuitry.
The SI5351 module shown in the link has an on-board 3V3 regulator. It should work with 3V3 (VIN), but some of the forums show it powered with 5V with the pull-up resistors on the SCL and SDA pins removed (see attached).
73, Dave

[ulmann]

Spoiler, не можете ли вы выложить фото как внутри Max Decodera ll расположен и подключен блютуз передатчик.

[Spoiler]

should work with 3V3 (VIN), but some of the forums show it powered with 5V

Спасибо, Dave(?), Вы как всегда конкретны и лаконичны. А я вот не догадался погуглить насчёт питания... А что это за чип там в качестве стабилизатора (на нём написано что-то вроде LG33)? Может, лучше его обойти?
А что, если не секрет, у Вас за никнейм - похож на позывной (from GB)?

как внутри Max Decodera ll расположен и подключен блютуз передатчик

Я его ещё не разбирал. Некогда пока, текучка... Просю пардону...