From: Tomas K. <de...@vo...> - 2010-11-10 00:17:13
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Jie, I have "toasted" both doughterboards and first accident is obscure for me too - I didnt even know that it was amp, so I dont know when the accident happened. I only guess it was strong signal over the air. If you worry about damaging RX I recommend attenuator usage. I have bought SMA Pasternack attenuators http://www.pasternack.com/category-Fixed-Attenuators-SMA-95.html (on eBay 4 pieces ~ 40$) Tomas > Tomas, > > After reading through the thread, it seems quite likely that my RFX900 > has a damaged RX amplifier just like yours did. I never connected any > strong signal to the RX, though it's possible that my handset may have > been positioned very close to the RX antenna at some stage. I had also > thought the component failure could perhaps be ESD related. I don't > think that I've used the USRP in any way out of the ordinary, so I'm > still concerned that I'll damage the working RFX900 sooner or later. > I'll order some amps and post again after replacing U4. > > Thanks, > > Jie > > On Tue, Nov 9, 2010 at 2:51 AM, Tomas Kopsa <de...@vo... > <mailto:de...@vo...>> wrote: > > Jie, > > in case of your problem, I refer you to this topic > http://sourceforge.net/mailarchive/message.php?msg_id=4B7D9F86.6080907%40volny.cz > and about 15 following > emails. Does the usrp_ffty.py output looks like this > http://sourceforge.net/mailarchive/attachment.php?list_name=openbts-discuss&message_id=4B7DCB70.2050403%40volny.cz&counter=1 > <http://sourceforge.net/mailarchive/attachment.php?list_name=openbts-discuss&message_id=4B7DCB70.2050403%40volny.cz&counter=1> > ? > > I suspect that one of your RFX900 has damaged amplifier U4, like > it was on mine. Did you connected somehow any strong signal to RX > of the issued RFX900 ? > (I use 3dB attenuator from this moment on RX) > > If the problem is truly in amp, it could be fixed quite easy, it's > not expensive > http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=MGA-82563-G > <http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=MGA-82563-G> > I only recomend not to replace it "at home", you need some > professional equipment like microscope, soldering station etc. > > Tomas > |