Author Topic: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)  (Read 7272 times)

Offline Mads Barnkob

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The RRU3928 is an outdoor remote radio unit. It processes baseband and RF signal data. With the Software Defined Radio (SDR)technology, the RRU3928 supports the dual-mode operation of any two modes of GSM, UMTS, and LTE through software configuration modification. RRU3928 has a dual-transmitter and dual-receiver structure, which supports higher output power and carrier capacity.

It can f.ex. do 6x GSM carriers at each 10 Watt and 1x LTE carrier at 2x10 Watt or 4x GSM carrier at each 10 Watt and 2x UMTS carriers at 2x20 Watt.

This is the initial teardown and later on I will release part 2 which is the circuit analysis video.

« Last Edit: January 08, 2019, 08:25:55 AM by Mads Barnkob »
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Offline Mads Barnkob

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 of 2)
« Reply #1 on: January 08, 2019, 08:25:08 AM »
/>


Above pictures shows the coaxial cavity band pass filter which in popular speech is called a duplexer or diplexer. Duplexer band pass filter explained: https://www.youtube.com/watch?v=HNaAQ3a7Duc



The power amplifier consists of a series of low noise amplifiers, general purpose amplifiers and power amplifiers. The first amplifier IC is not able to be identified. First identifiable IC is a NXP BLF6G22LS-40P 1.8-2.1 GHz 5-15 Watt dual amplifier that feeds the Infineon PTFB182012FC which is a dual power amplifier rated for 2x 10 Watt dissipation at 1.8 GHz. Anaren Xinger 1P503S, Anaren Xinger II XC1900A-03S and Anaren Xinger III X3C19P1-05S hybrid and direct couplers are used. One output circulator is used for double protection against reflected energy from the duplexer and antenna array.



The system boards 4 ADC/DAC main processors are unknown HI FPGAs that has a generic part number which is not identifiable. A Altera Arria II GX EP2AGX260 FPGA seems to be the heart of the unit and does all system control and communication with other units of the system. It has 16 transceivers that can run up to 550 MHz. 102600 Adaptive Logic Modules and 244188 Logic Elements available.



The digital to analog signal path starts with one of the HI FPGA ICs that sends a single highspeed bitstream to the Analog Devices TxDAC AD9122. It is a dual 16-bit DAC with a capability of 1230 MSPS. Analog Devices ADF4902 PLL and Analog Devices ADL5372 1.5-2.5 GHz Quad Modulators seems to be the next part of the path before the output power adjusting TriQuint TQM879005A which is a 1.4-2.7 GHz Variable Gain Amplifier. It can adjust 0.5 dB amplification at a 6-bit scale input.



The analog to digital signal path starts with 6 NEDITEK NDF9117 1747.5 MHz SAW filters (explained here: https://youtu.be/qO127zY3voE?t=963 ) which feed into a Skyworks SKY64341-11 1.7-2.0 GHz RF frontend. This has by other parts a downconversion mixer (explained here: https://youtu.be/qO127zY3voE?t=865 ) which by the use of a local oscillator can bring down the carrier frequency of the signal to something lower that is easier to work with.

The two separate lines now go through the Analog Devices AD8376 dual Variable Gain Amplifiers that has a bandwidth of 700 MHz at -4dB to 20 dB. The last stage is the Texas Instruments ADS58C20 which is a dual IF multimode receiver capable of working with both GSM / 3G / LTE. If this is the final analog to digital conversion IC or it is one of the HI FPGAs is hard to tell.



Good power supply layout with a lot of transient protection at the input. A single full-bridge of PSMN4R8-100BSE 100V MOSFETs is used for first stage voltage stabilization before the smaller high current planar transformers are driven by D70N1045 MOSFETs.
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Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #2 on: March 01, 2020, 06:22:28 PM »
So after having the amplifier board on my desk for the past year, I decided it was about time to do something with it.

I started as usual to identify all the components on the board.
This is what I came up with.



The first, pretty obvious thing is that the amplifier part of the board is basically symmetrical around the center.
Each of the halves has its own power contacts. The two outer contacts are for GND, the middle one of each side delivers the 27V Drain voltage for the LDMOS devices.

The power supply for the logic portion of the board is not symmetrical and supplies both halves. The big connector on the ground has some more GND pins, as well as one pin for what I call the digital supply.
This pin feeds some kind of LDO regulator.
I was not able to find the actual part that was used, however the drop out voltage is only around .6V and there is no switching component or Coil around, so I guess it must be a LDO.

The output of this LDO is +5V.
The regulator works with input voltages between ~5.6V up to around 9V. If you supply it with more than 9V the output goes away so I guess it has some overvoltage protection.

The 5V rail feeds all the OP484E quad operational amplifiers at the top as well as the AMC7812 devices.

Additional there are two LP2980 LDOs that produce two 3.3V rails.
One of them is used on the AMC7812 ICs. The other one feeds some mystery ICs which I believe are propably some RF amplifiers, since they are in the coupled path from the output.

I also managed to check all the SOT-23 devices for their type.
There are only two types used, some NPN transistors, as well as some P-MOS FETs.

The next step will be to figure out, which circuit was used for the gate biasing of each transistor.
Therefore I guess it would be interesting to find which ADC and DAC channels of the LMC7812 feeds which gate.
Knowing that might enable me to actually communicate with the LMC7812s.

saurabh

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #3 on: April 27, 2021, 01:34:37 PM »
So after having the amplifier board on my desk for the past year, I decided it was about time to do something with it.

I started as usual to identify all the components on the board.
This is what I came up with.



The first, pretty obvious thing is that the amplifier part of the board is basically symmetrical around the center.
Each of the halves has its own power contacts. The two outer contacts are for GND, the middle one of each side delivers the 27V Drain voltage for the LDMOS devices.

The power supply for the logic portion of the board is not symmetrical and supplies both halves. The big connector on the ground has some more GND pins, as well as one pin for what I call the digital supply.
This pin feeds some kind of LDO regulator.
I was not able to find the actual part that was used, however the drop out voltage is only around .6V and there is no switching component or Coil around, so I guess it must be a LDO.

The output of this LDO is +5V.
The regulator works with input voltages between ~5.6V up to around 9V. If you supply it with more than 9V the output goes away so I guess it has some overvoltage protection.

The 5V rail feeds all the OP484E quad operational amplifiers at the top as well as the AMC7812 devices.

Additional there are two LP2980 LDOs that produce two 3.3V rails.
One of them is used on the AMC7812 ICs. The other one feeds some mystery ICs which I believe are propably some RF amplifiers, since they are in the coupled path from the output.

I also managed to check all the SOT-23 devices for their type.
There are only two types used, some NPN transistors, as well as some P-MOS FETs.

The next step will be to figure out, which circuit was used for the gate biasing of each transistor.
Therefore I guess it would be interesting to find which ADC and DAC channels of the LMC7812 feeds which gate.
Knowing that might enable me to actually communicate with the LMC7812s.

Hi Da_Stier,
is the routing of the transmitter section done on a 2 layer board or a 4 layer board. I'm currently working on a design and the amplifiers provided by NxP don't provide enough room for a thicker board. so was curious to know how the stack up of these boards were

Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #4 on: April 27, 2021, 04:28:52 PM »
Hi saurabh and welcome (I think this was your first post, right?)


Most of the amplifiers, especially the simpler ones, like for example:
https://highvoltageforum.net/index.php?topic=1113.0
https://highvoltageforum.net/index.php?topic=765.0
have a double layer rogers PCB.
It is between 0.8 and 1mm thick.
The bottom layer is completly flooded with a GND polygon and soldered to the heatspreader.
Sometimes there are a few single control signal traces on the bottom as well.
The RF layout is done comoletely on the top layer.

Here is a side view of one of the "wet amplifiers":



The more complex boards use a combined PCB stackup most of the times.
They have a top portion of Rogers RF substrate, followed by a GND plane, followed by a few layers of conventional FR4 for all the signalling and stuff.
This is the side view of an Ericsson board.



You can see the white layer on the bottom (this is the top of the PCB with the RF stuff)
and the brown layers on top of that.
The boards of this kind, that I have seen have the double Layer Rogers and between 4 and 6 normal FR4 layers.

The Huawei board from this tread actually has a two layer Rogers board.
(which surprised me to be honest)
However the bottom layer is used for signalling in a few places, where no GND plane is needed.
(mostly underneath the DAC and control ICs in the middle)
Here is a side view of the Huawei board:



Let me know if you need anything else, I'm happy to help.  :)
And out of curiosity, can you share more details on your build, it sounds very interesting.



Greetings,
Michael

saurabh

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #5 on: April 29, 2021, 12:44:57 PM »
Hi,

You mentioned that the Huawei board in this thread uses a two layer Rogers board, and that the routing in certain regions was done below the board. An immediate question that popped up in my mind was, the heat sink is present underneath the entire board, if there is routing as well as ground lines below the board wouldn't they be shorted. or am i missing something here.

Thanks
« Last Edit: April 29, 2021, 12:50:00 PM by saurabh »

Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #6 on: April 29, 2021, 03:12:54 PM »
Hi,

your concerns are right of course.
If some of the bottom layer is used for signal routing, this section has solder mask over it, so it is protected.
In addition, the heatsink plate has pockets milled out in these places to provide another layer of safety.

As an example, you can take a look at this teardown, that Mads Barnkob did:
/>At 4:11 you can see how the typical interface between the heatsink and the PCB looks.  :D

Greetings,
Michael

saurabh

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #7 on: April 29, 2021, 03:44:33 PM »
Ahh that's a nice way to provide room for routing. Thanks.

Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #8 on: April 29, 2021, 08:00:18 PM »
I went ahead and searched the Huawei board (or what is left of it, I did a few experiments with it).
You can see the milled pockets and channels quite clearly.
You can also kind of see the green soldermask on the bottom, where the pockets are.
(not sure how much of it is visible on the picture)











Greetings,
Michael

Offline niko99

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #9 on: August 15, 2022, 12:42:36 AM »
I found such boards - for 2.1 - 2.2GHz band and 2.6-2.7GHz band.

How can I split PCB from metal board? I would like to do reverse engineering, and modify the amplifiers.

Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #10 on: August 15, 2022, 12:18:27 PM »
Hi niko99,

you can seperate them by heating the whole thing up.
You can use one of these soldering hotplates for it, it works pretty well.
I have used this model before, to do just that.
https://www.ebay.de/itm/113566952618?hash=item1a711e2caa:g:OSIAAOSwjthcQFSC
I usually set it to around 300 °C and just wait.
Make sure to do this outside, the flux will gas out quite a bit.

HOWEVER:
Why do you want to seperate the board?
There really isn't anything on the bottom to make this necessary.
If you do remove the board, you will damage it, which will make it hard to reuse.
If you want to reuse the amps, just work from the top.
Atleast from my experience, it won't help to take the board off, except if you just want to desolder the parts to reuse them seperately.

Other than that, feel free to post some picutres of your parts or start a new thread, I would enjoy to see someone else working on this sutff. :)




Greetings,
Stier

Offline niko99

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #11 on: August 15, 2022, 06:11:41 PM »
Hi niko99,

you can seperate them by heating the whole thing up.
You can use one of these soldering hotplates for it, it works pretty well.
I have used this model before, to do just that.
https://www.ebay.de/itm/113566952618?hash=item1a711e2caa:g:OSIAAOSwjthcQFSC
I usually set it to around 300 °C and just wait.
Make sure to do this outside, the flux will gas out quite a bit.

HOWEVER:
Why do you want to seperate the board?
There really isn't anything on the bottom to make this necessary.
If you do remove the board, you will damage it, which will make it hard to reuse.
If you want to reuse the amps, just work from the top.
Atleast from my experience, it won't help to take the board off, except if you just want to desolder the parts to reuse them seperately.

Other than that, feel free to post some picutres of your parts or start a new thread, I would enjoy to see someone else working on this sutff. :)




Greetings,
Stier

Thanks for Your reply.
I would like to use this boards as an amplifier - on amateur bands. Before retuning input and output matching networks, I just want to transmit within it's original frequency band - just to test it's performance.
But to use AMC7812 I need to find how it measures Drain current of every transistor. That was a reason why I wanted to get inside.
Do You have a better idea? should i rather do my own biasing, and not reuse AMC7812 circuit?

I tried to heat it up using my 853a yihua preheater, but it is probably too weak - after 20 minutes, pcb barely heats up to 60 degrees.
This is not enough to desolder anything bigger on the pcb - power divider, or power transistor.
I'm charging my camera right now - it makes high quality photos, so I will post them soon.

Niko

Offline niko99

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #12 on: August 15, 2022, 06:55:43 PM »
These are photos of my amplifiers.

Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #13 on: August 16, 2022, 02:49:48 PM »
Hi Niko,

sorry I didn't find the time to answer you yesterday.
So I will try to go through all your points now.  :)

I would like to use this boards as an amplifier - on amateur bands. Before retuning input and output matching networks, I just want to transmit within it's original frequency band - just to test it's performance.

Makes sense, I guess you want to use them in the 13cm Band then?
It will be interesting to see what works better, to get the 2.1GHz ones up or the 2.6GHz ones down.
In my experience, the 2.1GHz ones tuned better, however I have way less 2.6GHz samples so the comparison isn't quite fair.
It makes sense to test the amplifiers as they are, since I found some of them already work pretty well in the 13cm band and don't need any mods.


But to use AMC7812 I need to find how it measures Drain current of every transistor. That was a reason why I wanted to get inside.
Do You have a better idea? should i rather do my own biasing, and not reuse AMC7812 circuit?

I did some work for the AMC7812 as well, if I remember correctly. For me the problem was mainly time and that there was quite a bit of buffering, amplifying and voltage dividing, making it hard to get the actual gate voltage without A LOT of tracing.
In my opinion the bias circuit as is is propably one of the best if not the best option for a specific design, simply because it was made by someone who does it for a living.
So if you can reuse it, go for it.
However especially for testing or a very static HAM application, you are totally fine by just connecting a trimpot to every gate.
For the narrow band HAM applications, you won't need all the dynamic bias adjustments, that the many MHz wide LTE carriers need.


But to use AMC7812 I need to find how it measures Drain current of every transistor.

This would be my prefered order of options:
1: some amps have the drain of each transistor supplied by seperate VDD pins
(This is of course not really affectable by you and I think Huawei doesn't do this)
2: set all the bias to a known low value like 1V so you can check your gate channel mapping.
Then you can bias each gate individually and measure only this current
3: if none of the above work, just disconnect the gate bias and put a pulldown on the floating gate.
This way you can connect them one by one and measure each current by itself (or the difference for each added bias)

If you choose to disconnect somehting, always make sure to disconnect it after the first capacitors - seen from the transistor.
The striplines that connect drain and gate voltage to the transistors are calculated transmission lines, that transform the RF short of the capacitors to a RF open.
Therefore it is important, that they are nice Lambda/4 transmission lines.
If you cut them and bodge them back together, you can get some impressive RF flames / arcs.  ;)
So make sure to cut behind the red line.




I tried to heat it up using my 853a yihua preheater, but it is probably too weak - after 20 minutes, pcb barely heats up to 60 degrees.
This is not enough to desolder anything bigger on the pcb - power divider, or power transistor.

Yeah, I tried this as well.
I also tried a hot air rework station but you need closer to a kW of heat to get it hot enough, which makes sense if you think about how much heat these amps
are designed to get out of the carrier plate.


The finals on one of your amps look very intersting, I haven't seen this package before.
Looks like the left two ones are used in parallel and propably biased to operate in class A or maybe AB with the right one being the peeking amp for a doherty configuration,
biased in class C.




I found these small predriver transistors to be pretty fragile.
They die pretty quick by having to much bias current (max. 150mA !) or by being mismatched.
Especially if you drive them hard and the  next stage reflects a lot of power, they die instantly, keep this in mind.




One last thought for now, keep in mind, that your transistors need to be soldered to a backplate anyway, since the GND connection is made by the backplate.
So if you do choose to desolder the PCB from the heatspreader, you will need to solder everything back together before you can do any further testing.
This is one more reason, not to desolder it in my opinion.




Greetings and keep us updated,
Michael



Offline niko99

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #14 on: August 17, 2022, 02:47:49 PM »
Makes sense, I guess you want to use them in the 13cm Band then?
It will be interesting to see what works better, to get the 2.1GHz ones up or the 2.6GHz ones down.
In my experience, the 2.1GHz ones tuned better, however I have way less 2.6GHz samples so the comparison isn't quite fair.
It makes sense to test the amplifiers as they are, since I found some of them already work pretty well in the 13cm band and don't need any mods.

Yes and no. 13cm band is interesting, and I would like to reuse all amplifiers on this band,
but if some amplifier can't be retuned efficiently to this band, I still want to make it work on original band - just for fun and non-profit.


I did some work for the AMC7812 as well, if I remember correctly. For me the problem was mainly time and that there was quite a bit of buffering, amplifying and voltage dividing, making it hard to get the actual gate voltage without A LOT of tracing.
In my opinion the bias circuit as is is propably one of the best if not the best option for a specific design, simply because it was made by someone who does it for a living.
So if you can reuse it, go for it.
However especially for testing or a very static HAM application, you are totally fine by just connecting a trimpot to every gate.
For the narrow band HAM applications, you won't need all the dynamic bias adjustments, that the many MHz wide LTE carriers need.

You mean You didn't had time to make AMC7812 controller from MCU?
I would like to reuse board as much as I can - so I would like to avoid manual biasing of the amplifier.
Yesterday I found a mapping between DACs in AMC7812 and biasing circuits of each individual transistor device.
I also found, that small preamp transistor and medium amp transistors drains are connected.

Also, final transistors, have drain shorted to ground, and that really confuses me. I can't find any documentation about SGN26H181. I'm afraid, that datasheet is classified.
I suspect that  this may be GaAs pHEMT MMIC, which are seen between drain and source as short, when It's unbiased...
I think about skiping the final transistors, and try to run medium power section. Can I cut traces caming after circulator from medium power mosfet, just to solder there RF connector?


This would be my prefered order of options:
1: some amps have the drain of each transistor supplied by seperate VDD pins
(This is of course not really affectable by you and I think Huawei doesn't do this)
2: set all the bias to a known low value like 1V so you can check your gate channel mapping.
Then you can bias each gate individually and measure only this current
3: if none of the above work, just disconnect the gate bias and put a pulldown on the floating gate.
This way you can connect them one by one and measure each current by itself (or the difference for each added bias)

I will do it that way, but I'm curious, can I use 24V instead of 28V as drain voltage ?

If you choose to disconnect somehting, always make sure to disconnect it after the first capacitors - seen from the transistor.
The striplines that connect drain and gate voltage to the transistors are calculated transmission lines, that transform the RF short of the capacitors to a RF open.
Therefore it is important, that they are nice Lambda/4 transmission lines.
If you cut them and bodge them back together, you can get some impressive RF flames / arcs.  ;)
So make sure to cut behind the red line.

Fortunately I haven't made any cut so far.

One last thought for now, keep in mind, that your transistors need to be soldered to a backplate anyway, since the GND connection is made by the backplate.
So if you do choose to desolder the PCB from the heatspreader, you will need to solder everything back together before you can do any further testing.
This is one more reason, not to desolder it in my opinion.
Okk, You are right, It's no sense to destroy it.

Thanks for help, and Your attention.
When I will be done, I think about posting modifications on Github, so anyone will be able to make use from this amplifier( i have different ones for different bands, so let's reverse them all!! )
Niko

Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #15 on: August 21, 2022, 05:24:11 PM »
Hi Niko,

You mean You didn't had time to make AMC7812 controller from MCU?
I would like to reuse board as much as I can - so I would like to avoid manual biasing of the amplifier.
Yesterday I found a mapping between DACs in AMC7812 and biasing circuits of each individual transistor device.
I also found, that small preamp transistor and medium amp transistors drains are connected.

I meant that I didn't have enough time to trace out the cirucit completely and I didn't have the time to get the AMC7812 communicating with an Arduino.
(I'm not exactly good at the software side of things so this is the hard part for me most of the time.)
The AMC7812 had so many registers to set that I kind of lost my track, especially since time was an issue.


Also, final transistors, have drain shorted to ground, and that really confuses me. I can't find any documentation about SGN26H181. I'm afraid, that datasheet is classified.
I suspect that  this may be GaAs pHEMT MMIC, which are seen between drain and source as short, when It's unbiased...
I think about skiping the final transistors, and try to run medium power section. Can I cut traces caming after circulator from medium power mosfet, just to solder there RF connector?

That sounds strange yes.
I did take a look as well but I couldn't find anything meaningful either.
I guess you will have to try and see.
Sure you can cut the trace or maybe find an AC coupling cap that you can desolder and use its pads to connect to.
This is something I like to do, since it is pretty much reversible is necessary.


I will do it that way, but I'm curious, can I use 24V instead of 28V as drain voltage ?

Sure, the achivable power will be lower but it will work just fine.
But make sure to set the bias with the correct drain voltage applied.
(If you want to use 24V, set the bias with 24V)


Greetings,
Michael

Offline niko99

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #16 on: August 22, 2022, 11:48:58 AM »

I meant that I didn't have enough time to trace out the cirucit completely and I didn't have the time to get the AMC7812 communicating with an Arduino.
(I'm not exactly good at the software side of things so this is the hard part for me most of the time.)
The AMC7812 had so many registers to set that I kind of lost my track, especially since time was an issue.


I think that document I attached may help You.
* new-capability.pdf
It convinced me, that the fact that AMC has a lot of registers, doesn't mean that You have to write em all.

Greetings,
Niko

Offline Da_Stier

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #17 on: August 24, 2022, 08:06:23 AM »
Hi Niko,

thanks for the document.
It is very interesting.
Do you know what it is supposed to be or what kind of backstory it has?
It somehow feels very "professional" and expensive but the work shown also feels kind of basic and hobby level.

I found a lot of "reverse engineering" companies, that would sell you their results for ericsson stuff.
Their prices were in the range of 3500$ but according to the freely available table of contents, they would sell you all the schematics and software ... who knows.
I found a russian company that did something similar for an old ericsson model ... they also provided rar archives of all the cell site management software, for free, very strange.

I looked a bit into the company that made the document you provided but couldn't gain any deeper understandings.

Non the less, I actually got very interested in working on this stuff again, maybe I will have to so some more reverse engineering again.  :)



Greetings,
Michael

Offline niko99

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Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #18 on: August 25, 2022, 11:58:52 AM »
Do you know what it is supposed to be or what kind of backstory it has?
It somehow feels very "professional" and expensive but the work shown also feels kind of basic and hobby level.

I have no connection with the company or people who did this. I wouldn't have posted this pdf if i had:) . I just found it in scribd.

Yeah, hobbyist can do SPI/I2C sniffing, as well as reverse engineering with contact tester(beeper in multimeter).
I agree, this doc looks very professional. It's a pity that they didn't posted analyzed PCB(but i suspect they did that too).

I'm curious is it legal to post publicly detailed documentation of reverse engineering of that PA, and using it outside original device.

I found a lot of "reverse engineering" companies, that would sell you their results for ericsson stuff.

I'm focusing mainly on H-letter power amplifiers, because they are, and will be easily obtainable - especially when/if H-named mobile equipment will be banned in Europe.

Non the less, I actually got very interested in working on this stuff again, maybe I will have to so some more reverse engineering again.  :)

Good luck, I will also work on that in my spare time. It's better when You know, that someone also cares about it.

Best regards
Niko

High Voltage Forum

Re: Huawei RRU3928 1800MHz radio base station teardown (part 1 and 2)
« Reply #18 on: August 25, 2022, 11:58:52 AM »

 


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