Which UFL PCB connector is the BT transmitter?

motleypixel

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Jul 12, 2025
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Hi folks,

I will cut to the chase, the only issue I and a number of other folks have with the Ultra is the poor BT transmission strength. Albeit, it's at the bottom of the functionality stack of this wonderful device. I even measured it vs my original FiiO BTA30 Pro desktop DAC/BT transceiver in the same spots and the Ultra's is quite a bit weaker. So my thinking here is (and this is all on my own, fully understanding if I do it it will VOID warranty and this is the record in and of itself).

Per this tear-down, does anyone know which UFL PCB connector is the BT transmitter? If I knew, then it's an easy jump to a bulkhead SMA antenna connector. Of course before drilling a hole in the rear of the case for this antenna I would test for signal strength improvement.


This is the jumper/connector I would use with an SMA antenna: https://sixfab.com/product/waterpro...sa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1

Thank you.
 
Don’t know if it’s of direct help, but someone re-cased a WiiM pro some time back and fitted an external aerial.

 
Don’t know if it’s of direct help, but someone re-cased a WiiM pro some time back and fitted an external aerial.


Thank you I responded:

There is a school of thought that RF & EMS waves are detrimental to sound quality...

Great work on the case. I came here after looking for a tear down video on youtube which exists but doesn’t specify which UFL connector is for Bluetooth. I’m still at a point of discovery, not sure if there are separate UFL connectors for BT transmit, BT receive and WiFi?

Reason is because I’m only having issues with the BT transmission from the Ultra to BT headphones. Wifi works fine (close to my router), BT receive works fine but I have no need to use it. BT transmit is giving me some issues with a few headsets BT 5.0. I have a business pair of 5.3 that seem to work better but the range is not great.

I installed a radio meter on my phone and compared the Ultra with my previously used DAC/BT Transceiver and the previous was quite a bit stronger (FiiO BTA30 Pro). And no, before anyone asks why not use that…the answer is no 😊

So in your post here, can you point out the PCB connector use for BT transmit? Is it a std UFL connector where I could put something like this in it’s place? https://sixfab.com/product/waterpro...sa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1

I’m attaching a screenshot with a red circle, is this the landing?

Thank you.
 

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It's a bit strange that you have these issues with the BT on the Ultra. I can walk around the garden and two floors up from the Ultra in the living room without any issues on the headphones.

How is the Ultra placed? The antenna is in the bottom of the device. Do you have any obstructions there?
 
It's a bit strange that you have these issues with the BT on the Ultra. I can walk around the garden and two floors up from the Ultra in the living room without any issues on the headphones.

How is the Ultra placed? The antenna is in the bottom of the device. Do you have any obstructions there?

Thanks @hgo58 I’m attaching pictures to spell out the preverbal 1000 words. But essentially, it lives exactly where it will remain, right where my FiiO BTA30 Pro DAC/BT Transceiver used to live that never gave me issues with various streaming quality and/or streaming distance with a few different BT headsets. Sitting on top of the Ultra is a S.M.S.L. PL100 CD Transport, I have tested with it off, on, playing a disc and completely removed with zero difference.

My problems so far are: Sony XM-4 having poor streaming quality, start off okay “usually” for a song maybe two if I’m lucky, then just partial digital “garbal”. This is confirmed with a number of users trying with their XM-4s. Anker Soundcore Life Q30’s don’t have any streaming quality issues, just microsecond drops from time to time when I go just outside the listening room/area, or say 20-25’. My work Dell BT 5.3 conferencing headsets seem to work the best, but still not near the range of the FiiO. I used to be able to go into my garage w/o any dropping, but not anymore.

Thank you.
 

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Thanks @hgo58 I’m attaching pictures to spell out the preverbal 1000 words. But essentially, it lives exactly where it will remain, right where my FiiO BTA30 Pro DAC/BT Transceiver used to live that never gave me issues with various streaming quality and/or streaming distance with a few different BT headsets. Sitting on top of the Ultra is a S.M.S.L. PL100 CD Transport, I have tested with it off, on, playing a disc and completely removed with zero difference.

My problems so far are: Sony XM-4 having poor streaming quality, start off okay “usually” for a song maybe two if I’m lucky, then just partial digital “garbal”. This is confirmed with a number of users trying with their XM-4s. Anker Soundcore Life Q30’s don’t have any streaming quality issues, just microsecond drops from time to time when I go just outside the listening room/area, or say 20-25’. My work Dell BT 5.3 conferencing headsets seem to work the best, but still not near the range of the FiiO. I used to be able to go into my garage w/o any dropping, but not anymore.

Thank you.
That looks almost like my setup. With the Sennheiser momentum 4 I can move at least 30m outside without issues, as long as there are no walls. Inside it works better 3 floors. So not sure why you have these issues. Maybe a badly assembled Ultra?
 
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