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Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
Huawei RRU3908 base station teardown (part 1 of 2) The Huawei RRU3908 is an outdoor Radio Base Station with one to four carriers and one to six sectors at 20/40 Watt RF output power per carrier.
Huawei RRU3908 base station circuit analysis (part 2 of 2) [fixed audio]
Nokia Siemens Flexi BTS base station teardown: Power amplifier (part 1 of 2) Teardown of a Nokia Siemens Networks Flexi WCDMA base station. This have been in service as a 6 antenna GSM system for mobile telecommunications. GSM/EDGE, WCDMA/HSPA and LTE capable. 2x40 Watt output power.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I took apart a wcdma base station a few years ago - fascinating. The LDMOS power transistors were interesting to experiment with, gate bias temperature compensation is definitely required for class-A and class-B linear amplifiers, and driving them also provides a challenge. So if rf interests you, don;t cannibalize the unit too quickly.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
Very nice, Mads, as usual.
Have any of you ever encountered a base station with cryocooler for liquid nitrogen? Please excuse me if that's been discussed here before.
That would be for "high temperature" superconducting materials.
About 15 years ago, a lot of research went into passive microwave filters, using HTS material in thin films on insulating substrates. In this 2003 paper, , the authors say As a result of commonly available test procedures, a de facto standard emerged for surface resistance measured at 10 GHz and 77 K. An HTS film was early on deemed to be of “device quality†if this value fell below 1 milliohm [per square]; modern films typically measure below 250 microohms.
For room temperature copper at the same frequency, I figure the skin depth is 0.66 um, and the resulting sheet resistance is about 30 milliohms per square. That's not counting the penalty for surface roughness, which is sometimes increased on purpose to improve the mechanical bond in circuit boards.
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
I am not going into RF at this point of my life, there is enough to do in regular electronics, so most of the reuseable parts make their way to HAM community.
You are not the first to ask about cryo-coolers, but I have yet to find a unit with it and that is among hundreds of units I have seen thrown out. I guess that must be used in very special applications and not something as normal as "consumer" base stations
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
I finally got the circuit analysis finished and there is a whole lot fo ground trying to be covered in just roughly 20 minutes, so many details are left out only trying to cover some of the basics and let people catch the interest and seek out more information.
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Huawei and Nokia Siemens base station teardowns
