Air-Band - Is it possible? (Photo)

[Cofeman7]

Is it possible to use an airband?
What kind of firmware is this?
The photo was taken from a Russian-language forum.
https://4pda.to/forum/index.php?showtopic=1112172&view=findpost&p=140370138

[Yuradol1972]

Hello, this has already been discussed here. #129

[lohtse]

Hello, this has already been discussed here. #129

but what filter are they using in the image above??

[G8PTN]

Hi,
If you are referring to the AM filter bandwidth, it would normally be set to 6kHz, which is the widest option in the SI4732-A10.

If you are referring to the RF side, it depends on the circuitry in the external down converter. Normally there is some sort of filter to reduce unwanted images during the mixing process.

73, Dave

[Yuradol1972]

Hello, for the AIR range in Chinese firmware https://oshwhub.com/abcdef2022/full-band-network-2-in--1-radio need an external 100 MHz converter

[lohtse]

Hi, If you are referring to the AM filter bandwidth, it would normally be set to 6kHz, which is the widest option in the SI4732-A10.

If you are referring to the RF side, it depends on the circuitry in the external down converter. Normally there is some sort of filter to reduce unwanted images during the mixing process.

73, Dave

The image the OP added suggest no external filters are in use which is why I asked mate...

[G8PTN]

Hi,
The external down converters from the Chinese market place sites have either a 100MHz or 110MHz LO and the RF input does have basic filtering as shown below to try and block frequencies below the LO at the input to the mixer.
73, Dave