The Ware for July 2014 is shown below.
Sorry that posts and updates have been infrequent the past few months — been really busy!
This entry was posted on Wednesday, July 30th, 2014 at 5:07 pm and is filed under Hacking. You can follow any responses to this entry through the RSS 2.0 feed.
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Looks like some kind of bidirectional RF amplifier. Signal path starts small transistor and ends up big transistor, left to right at the bottom and right to left at the top.
Will have to be at two frequencies, obviously.
Cellphone booster?
amplifier
Looks like an RF diplexor of some sort – signals at different frequencies going in different directions
Two similar RF paths back to back, MMICs and SAW in the way. That is a narrow band preamplifier, for a bidirectionnal RF signal, probably high in frequency, something like 1-3 GHz range.
Not higher than ~4 GHz, otherwise PTFE (rogers) PCB would have been used instead of FR4+green varnish.
There is a copper-colored block in the middle and visible signs of thermal paste – or is that reflections from the machined zones? It does not seem to be a high power device. The metal in the middle might just be for shielding both paths, and the orange color is anodizing.
I would have said a switch, but both paths are powered at the same time, there is no power switching on each branch. BTW, notice the nice effort in the decoupling network, caps are very close to where they are needed, and there are additional caps on the long traces. DC is coupled to the RF traces via chip inductors.
That tells me that the smd xtal like parts that seem to “split” the signal are directional couplers, and that each branch amplifies signal travelling in a single direction.
I have no exact idea of what this device could be, maybe a wifi/bluetooth/something microwave range extender? Each (BNC? TNC?) plug gets an antenna over a long cable, and the device amplifies signals in both directions.
However the “custom” bottom left screw looks like it could be an amateur device, not a commercial one.
I can’t read what’s written on the filters, but each branch probably deals with different frequencies, however close.
If not, then each branch would pick up the output of the other, and that would be a ring oscillator :)
It is clear that:
-each branch deals with only one direction (MMIC gets DC bias on the output lines)
-3-way devices are directional couplers
-these signals are close in frequency, since the couplers only have limited badwidths
-xtal-kile with two ports are SAW filters; each line will probably be centered on a different frequencie, and have strong rejection for the frequency of the other branch.
So it could also be a low power GSM test repeater, where both uplink and downlink are amplified, for test or indoor use.
What appears to you as thermal paste on that block in the middle is just an area that isn’t anodized. Either the holes are where they held the part when it was getting anodized, or the anodizing came off when they drilled the two holes.
Yep, I got that later but did not post again for this minor fact :) Now it’s done, the anodizing was removed where the box was machined.
I’m guessing it is a jammer for cell phones and/or gps.
GSM indoor amp. The filter in the upper right is the right frequency, and the power range seems about right for that application.
yes GSM (of cell amp of some sort) – the NDF8977s duplexors on either end are at around 900/947MHz and designed for just that
Looks like this one:
http://tinyurl.com/ng2ml5h
Here it is, this one “Booster Mini 980”, all the right frequencies and the LEDs in the right place:
http://www.aliexpress.com/store/product/10m-Cable-Antenna-GSM-Repeater-Booster-Amplifier-Receivers-900Mhz-Cell-Phone-Mobile-Signal-booster-amplifier-repeater/630939_1671624334.html
yay \o/
No name gsm repeater
http://m.aliexpress.com/item-desc/566235711.html
I’m curious about the unpopulated parts like LB10, where the signal trace continues under the footprint of the LB part. If LB10 were to be populated, would the trace under it be cut?
I also note some signs of rework, e.g., at the lower right, C26 looks like something I might have soldered myself. And just why are the LEDs so oddly placed?
FWIW I assume Jonathan is on the right track. “GSM RF Repeater” produces a lot of pictures of brass/copper-colored boxes in a similar size range with a pair of antenna connectors, a power connector, and red/green LEDs for power and signal. so while that’s not real strong evidence, it doesn’t disconfirm anything about the theory.
Also the blurred section of the silkscreen is pretty obviously saying “GSM” if you look at the thumbnail and squint a bit :)
At the factory they will often start omitting parts until a large segment of the production run no longer passes functional testing. The ones that fail the test get some of the omitted parts added to it until it does pass.
The fewer parts, the more money they make, even after paying someone to rework the failing devices. ( They pay the person anyway, might as well have them doing something. )
I once fixed an LCD monitor by adding an omitted resistor from an RC circuit that was part of some safety mechanism. After years of operation the value of the capacitor changed enough that the safety circuitry started detecting faults that didn’t exist. I would like to point out that at the time it was already old enough that it would have been worth replacing; so even with a missing part it still worked for a significant period of time.
This isn’t a China-only thing either, it started in the US! http://en.wikipedia.org/wiki/Muntzing
It’s one of the variants of the “AT980” cell phone amps.
Eg: http://www.dx.com/p/twp-at980-500mw-900mhz-890-915mhz-935-960mhz-gsm-cell-phone-signal-amplifier-booster-golden-318662
That looks like it’s the right board layout (RF on a central axis, barrel jack with two LEDs equally spaced between the jack and the RF input), but the RF connectors seem wrong: most of the AT980s use type F, which this looks like, except that it appears to be panel mount. A bunch of the other GSM amplifiers use type-N connectors, which is what you really should use for GSM.
It is definitely GSM, though: the upper path ends in an NDF9296, which is easy enough to find: 935-960MHz saw filter (http://www.winnsky.com/res/winn-sky/pdres/201211/20121108093322777.pdf).
The duplexers are NDF8977s (http://www.winnsky.com/res/winn-sky/pdres/201309/20130928115939378.pdf), which are good for both the 850 and 900MHz bands, which suggests that this is an 850+900 GSM amp.
Add to this that a lot of the AT980s are “935-960MHz” amplifiers, and it’s a pretty strong case for it.
Err, that should say that the upper path “begins” in an NDF9296, since the right hand side of the board is the outdoor antenna.
My guess is its one of those bidirectional Wifi signal amplifiers. The green LED is for power and the red is probably a IO activity LED.
Is this a prototype? Its got self tapping screws on the connector on the left side. The rest look like machine screws. There looks like a few (poor) hand solder jobs. Bits of solder left on vias too.
cannot work, with wifi, tx and rx are on the same frequency, so each branch of the amplifier would bite the tail of the other branch :)
Great. Thank You for sharing!
Its the continuum transfunctioner. I knew bunnie had it.
IMEI (International Mobile Equipment Identity) is a unique 15-17 digit
number given to GSM as well as iDEN wireless phones.
Usually this is normally created to help recognise each wireless phone
and also in situation the cellphone is missing.
Primarily it is actually created to find each mobile phone
and whenever it has been lost or stolen,
to block the cell phone from being utilized simply by a different inividual.
When a the device user sees that his or her device
has been snatched, it could possibly blacklist the International Mobile Equipment Identity code and
then lock it away of the network. For those who have a dual-SIM phone, you are
going to notice a pair of IMEI digit numbers, one for each SIM slot.
Besides cellphones, this particular IMEI codes are usually marked in netbooks along with wireless
internet cards, 3G or 4G tables. Today, along with IMEI, a number of devices include MEID too,
(Mobile Equipment ID, a super set of IMEI).
There are numerous approaches to find out the IMEI digits.
One approach may not effectively function with almost all kinds of
products. Let’s take a look into the various technique of determining this unique IMEI/MEID code.
This digit codes is located on each and every cell device.
To help locate this number, switch off you cellular phone ,
take out the cell battery, and then take a look around the empty cell battery
slot just for a whitened label noting the particular IMEI
digits which is 15 or perhaps 17 digits.
The other typical means for you to find is usually simply by dialing 5-digit number *#06#.
By the time you type the last digit, the IMEI number will be shown on your cellular.
However, it may not perform for other sorts of mobile handsets.
For instance, an apple iphone together with the Verizon network
dials the particular digits as a calling number, and then will not necessarily return the IMEI
digit number. In case your cell device is missing or perhaps
stolen, all you ought to do is to find the original packaging for your cell phone gadget and
identify the particular barcode label attached on box.
IMEI is typically placed along with the barcode and serial number on the cover of your box.
Different cell phone devices may have different
options for retrieving the particular IMEI digit number. Why don’t we look at some of them.
For Samsung mobile units, the person who has installed
the Samsung KIES app in his or her computer’s desktop to synchronize their own device
with the computer, they can get the IMEI digit codes from the details stored on the Laptop.
To actually implement that, simply just open the Windows registry through ‘regedit’ and navigate: HKEY_CURRENT_USER\Software\Samsung\Kies\DeviceDB\.
In the entry, you will definitely obtain the particular IMEINUM and also DEVCONINFO keys.
The keys carry the IMEI number of the phone.
For individuals who use Nokia cell phone devices, the OVI (Nokia
PC Suite) Desktop application can certainly help acquire the actual IMEI digit codes.
Through the Nokia PC Suite app, navigate: My Computer->C Drive->Users->(Your user Name)->Application Data->Local->Nokia->Nokia Suite.
After you open any of the folders you are going
to observe folder names which would have IMEI digit codes. Motorola devices ; The moment you switch on your phone,
press the following key set in quick sequence: # * [menu] [right arrow].
And then scroll down till you see IMEI/SIM ID.
IMEI (International Mobile Equipment Identity) digit number monitoring using Android
cell phones: this can certainly make use of Google’s Dashboard application to help you get this unique digit number.
First login to the Google account, once in the Dashboard,
broaden the Android item list which generally is 4th on your listing.
After that, take a look for your phone model on the list.
It’s IMEI digit codes are going to be shown right next to it.
For individuals who are using iPhone or maybe iPad, this is exactly how you could
do: from the home screen press ‘Menu’, then simply
open the ‘Settings’ window, move to ‘General’ move to ‘About’
field, right there you will observe MEID and then to
the right of that code, a 14-digit number which is
certainly your IMEI number.
Good details you have shared and this kind of circuit board.