Hi,
I am currently using aptx able bluetooth receivers to spread the sound from my studio to bedroom, kitchen and living room. Unfortunately pairing is a pain and latency sucks.
I am still having a 1 w board and was wondering whether I could just use this instead.
On Aliexpress receiver cost 2-5 Euro.
If I used the board what kind of antenna could I use. Obviously the smaller the better. I am not heading for range. Also what psu would be suitable? Could I get away with a meanwell switching supply, a switching supply that delivers more than 12V and regulators with caps behind or would I have to use a transformator? Does the psu have to be shielded? I am still having an empty 1 he rack case.
I attached a photo of the board. I suppose I can just feed the mpxed audiosignal where the satcan out is soldered to the pcb.
Thanks for helping.

1 W is far too much! Around my house, I use a 100mW PLL exciter board with a stereo coder, and a basic stereo limiter feeding it. The antenna is just a ¼-wave vertical, and it's ample power for house and garden. Most rooms in the house have receivers of one sort or another,and all of them receive the signal easily.

Perfect, Thanks a lot for helping

I use one of these
https://www.aliexpress.com/item/1005003527877677.html
can use in the car also
lots of power will even cover a big field. or a few LOL

All of the replies are correct, you shouldn't do it but if you're going to do it anyway... 70cm or so of solid core wire for the antenna, any regulated 15 Volt power supply rated over 2 Amps or so, and if you hook the audio into the pin on the "MPX Level" preset closest to the satellite tuner module you can still use it to control the volume. If I was doing this I would remove the MPX Level preset and the 2N4427 then connect the antenna to the center pin of the transistor, the audio to the center pin of the preset, use an offboard pot for the audio level and put it all in a metal box with connectors for power, audio and antenna on it. This would be better for playing with. 1 Watt could carry for a half mile or more - even into a bit of wire, the 2N4427 costs 3-5 quid, uses a lot of the 2 Amps of power and may blow or be hot and unhappy into such an aerial.

I doubt you'd need much of antenna using this board with its approximately 1Watt output. You can get away with a short length of coax that has 2x 100 Ohm resisters soldered on the end "in parallel" for a dummy load. There will be so much leakage from the unshielded load @ 3mtrs, it'll cover a typical home and garden. I can demonstrate with a video if required.

For the PSU you can use a baby RS-15-15 Meanwell SMPS to power the board. The most power hungry devices on this board are going to be the Satcan and the 2x Linear Voltage Regulators that power it. Thats approximately 250mA, and about double that with an LNB connected to the F Socket.

The RF section of the board will consume around 110mA, and the PLL Logic around 35mA. So in total you should see something close to 400mA total current consumption, and something close to 650mA with and LNB connected to the satcan.

So total DC INPUT Current = 6W without LNB, and 9.75W with LNB

The Meanwell Model RS-15-15 is a 15W SMPS which is more than ideal. Thats 15V @ 1A.

I would try using a 10dB attenuator between the 1W output and the unknown antenna for indoors use. The 100mW at the output of it is more than enough to provide noise free stereo around the house.
This way, you lose 900mW into heat, but you protect the output transistor from being fully unmatched to the aerial, as the attenuator will provide some rough (but lossy) impedance adaptation.

Thanks a lot for helping.

I'm not familiar with this transmitter i'd have to have a closer look, suppose you could remove the output transistor and pass on whatever signal was there to the output filter?, it would be enough to cover a house or whatever, maybe the voltage could be lowered I don't know?, as it is one way to directly lower the output. Short antenna attached directly to the transmitter would limit the range, not sure it would save the transistor.

Thanks everybody for helping, I ordered the linked item which works great inside my flat.