04-30-2022, 09:51 PM
(04-30-2022, 03:50 PM)Billthompson Wrote:(04-30-2022, 01:58 PM)TheBusyWizard Wrote: After a bit more time and research, I have ordered some parts to work on actualizing this. I plan to hijack the coax running to the sub-assembly board, along with something for switching. I'll be using an MMCX jack for my purposes, and will modify the chassis as necessary to accommodate the connector. I'll post pictures and details once everything arrives. All of the parts were easy to source from Mouser.com, though one could also get it on Amazon, albeit with a little bit more hackery.
I cant wait to see how it goes. The patch lead to switch connection is a weak spot. Would love to see it as easy as aux port.
My family has been using older phones with external antennas for years to get service in rural areas.
What im seeing is most motherboards have micro switches already installed between radio and antenna for factory testing, however they are tough to access and not physically up to repeated cycles. The micro switches on this s10 board have been removed, new larger solder pads installed and more robust older model switches installed. First solder attempt was no good but should get second attempt back next week for testing. Would be nice to have option manufactured into phone.
switches are off a s4 board
patch lead for switches https://www.amazon.com/gp/product/B07H6P...UTF8&psc=1
here is another page with various patch leads and demonstration of older phones with external antennas https://www.telcoantennas.com.au/patch-l...-galaxy-s4
The u.FL / w.FL style connectors have extremely low cycle tolerance IME. (In my less seasoned days, I've destroyed more than one on the second cycle... experience has improved this though.)
The biggest problem I anticipate is in reliably switching between the two signal paths without causing signal degradation or risking damage to the radio from reflections. Devices exist to handle this kind of thing, but I don't know how easy it will be to integrate. I'd like to include a physical switch (even a DIP switch perhaps) near the external connector.
My goal in the whole thing is to splice into the existing coax cable running between the main board and the secondary board. A good reference is here: https://forum.pine64.org/showthread.php?tid=15474
I will leave the existing "switched u.FL" connector, as well as C2 (as labeled in the linked post). This should provide the most reliable option. (Specifically, the least soldering / desoldering on my part.)
Once I've found a suitable RF switch for this project, I'll post a list of the parts I'm using. Once my PinePhone and all the parts arrive, I'll dive in and post about it.