Thanks for looking into this. I was trying to figure this out by looking at the pictures, and it appeared to me that there is an unpopulated RX3.
I think it is pretty minor modification for an experienced tech, so it can be converted to region specific bands as needed. On Tue, May 28, 2019 at 10:50 PM Mychaela Falconia < mychaela.falco...@gmail.com> wrote: > Serg wrote: > > > Seems like nice module, I see that it has at least 3 variants A/B/C, > could > > not find a good document in English what is the difference. > > It can be seen from Songbosi's huawei.jpg picture that the B version > is Calypso-based, whereas the C version is LoCosto-based. Back in 2013 > I made the decision to base my work on the Calypso chipset rather than > LoCosto, and this decision is now enshrined in the FreeCalypso project > name - and I am not switching. > > If Serg or anyone else feels like playing with LoCosto, you are on > your own. > > > Also seems like it has dual band SAW filters installed in B version, so > > additional components need to be installed in order to make it tri-band > and > > following the re-calibration process executed. > > Looking at Songbosi's huawei3.jpg picture (detailed view of the > component side of the board), it can be seen that the board CANNOT be > modified from dual-band to triband. One can remove DCS band support > and add PCS band support in its place, but it is not possible to have > DCS and PCS on the same board without redesigning the PCB. The antenna > switch only has two Rx paths coming out of it, not 3, and as you can > see in the photo, each goes through what looks like a series capacitor > acting as a high-pass filter. The layout is done in such a way that > the series capacitor for the high band Rx path can be populated in one > way for DCS and in another way for PCS, but you still can't have both > at the same time with this PCB design. > > To Songbosi: for my experimentation purposes I don't mind getting a > dual-band modem module without PCS band support: even though I am > located in USA-occupied California, I won't be operating the modem on > live airwaves here, instead I do all GSM RF testing on my CMU200 > instrument, and with that instrument I can operate in any band in my > lab. I would indeed be interested in getting a few of these modules > for experimentation and further reverse engineering, and Songbosi's > asking price is very cheap, but I would really need a breakout board > for the interface connector. > > M~ > _______________________________________________ > Community mailing list > Community@freecalypso.org > https://www.freecalypso.org/mailman/listinfo/community > _______________________________________________ Community mailing list Community@freecalypso.org https://www.freecalypso.org/mailman/listinfo/community
