Investigating In-& Outdoor DVB-T2 Antennas
Recently my second outdoor DVB-T2 antenna also refused amplifying the TV channels to my DVB-T2 receiver. So I started examining both antennas trying to find out what was wrong with them. My second now also defect antenna was called MAXIMUM DA-4000 LTE. Its original Box is shown next on the left. Only my old indoor KPN DVB antenna still worked in one spot in my living room. Because my glass living room windows blocked any signal from entering my home.
Above on the right my old first long ago used but also defect KÖNIG ELECTRONIC KN-DVBT-OUT11 active outdoor DVB-T2 antenna is shown.
And when I compared both internal printed active antenna circuit boards they looked very similar. In the meanwhile I already had ordered my now third outdoor antenna. But because they apparently keep going out of order for no obvious reason I wanted to find out what happened to my first 2 antennas that stopped working after just operating for a couple of years.
First E0792-03G board below is of my König antenna. It had some rainwater damage on its connector before but I had fixed that. And it had worked for a couple of months until it failed again.
Previous photos showed both sides of that König antenna pcb.
Next photo shows one side again but now with all the coils and wire connections on the other side drawn in with red ink.
None of the passive components were damaged or out of spec which only leaves the active part being the tiny 6 legged smd IC marked U1 with its top marking 2H5.
I made above clear close-up photo of IC U1 with my Mustool G600 Digital 1-600X LCD Microscope. That was bought on Aliexpress in the past but originally had extremely bad firmware. It often made me crazy! It kept freezing after just taking a photo or a video and afterwards needed to be reset every time over, again and again! And of course no support or upgrade fw from the Chinese seller!
And old fw version 1.0 in bios S25FL208 kept refusing to take photos without freezing afterwards. Luckily I found on a forum an improved v1.1 fw upgrade that fixed all previous issues! It was mentioned as : Mustool G600 LCD Digital Microscope Board KHE-H39G-v1.1 25q80 PN25F08B. [Here is page 2 of the website where the FW download can be found: https://mekatronik.org/forum/threads/mustool-g600-mikroskop-firmware-update.2227/page-2]
But before I was able to flash my original S25FL208 bios I noticed that none of my other universal programmers recognized my eeprom, except my good-old RT809H that had no problem with my bios.
So after I carefully had opened my G600 Microscope and removed my original bios on position U9 I reprogrammed it with my new found v1.1 firmware (also 1MB bin file) which shows as v1.3 in the Menu. I however first had to remove the sticker that blocked any access to the boards on top of the lithium ion battery pack inside my G600. And I carefully disconnected the battery pack and its + and – wires from the board and after that all flexprint cables. This to avoid breaking anything in the process and for better access. After I had improved and reassembled my G600 LCD Microscope, I continued with my DVB-T2 antenna repair investigation. Next 4 photos show more of the inside of this now very handy finally correctly working rechargeable portable Microscope. Many thanks to the person who made this new version and shared it!
Above photo showed the reset button of my G600 LCD Microscope that previously was used many… many times. But now finally was relieved from its heavy duty job!
Back to my previous König antenna with active IC U1 marked 2H5: Nothing was found that explained the used component when searching for that 2H5 smd code. But I did find what chip could replace this HF amplifier by looking at the PCB tracks to U1. Obviously it had to be a 5V chip. And also the chip should have a decent HF bandwidth so it could be used as DVB-T2 amplifier. It appeared that many HF amplifiers made by manufacturer NXP had the same size and the same pin configuration of the here used U1 chip. And it also was the right TSSOP 6 size chip, also called SOT363 chip size package.
So I decided to order a few BGA2851 5V IF wideband DC up to 2.2 GHz amplifiers. Although they were internally matched to 50 Ohm, I still wanted to try if they would work on my probably 70 ohm DVB-T2 receiver. Also because I couldn’t find any other matching amplifier chip like this MMIC amplifier chip. And when I have received and replaced the tiny chip I’ll will know!
Now over to my almost identical second newer but also defect DVB-T2 MAXIMUM DA-4000 LTE outdoor antenna. IC1 looks exactly the same on this DVB-T711 v3.0 marked board in size and in smd pin configuration!
Again my now great working G600 Microscope made a perfect next shown snapshot of IC1.
But this time our again unknown IC1 had smd code 2HF. Also that code gave no useful info whatsoever on what component was used here. However this looked exactly like the same size and pin configuration of our previous mention U1 smd chip used in the König DVB-T2 antenna.
The pin configuration that is used can be checked in the datasheet of this BGA 2851 IF amplifier. In above IC1 photo both connected bottom pins on the left and the middle are ground. The bottom pin on the right is IF input. The top pin above that on the right must be Vcc 5V (5V DC fed in coming from the coax IF DVB-T2 input port of the receiver) , and the top middle pin is ground with the top pin on the left being IF output (back into the receiver).
And previous photo taken with the G600 Microscope revealed both used smd diodes D4 and D1 code A7W being BAV99 diodes. Which must be the same high speed diodes that originally are used in the König DVB-T2 antenna amplifier.
Now over to 2 other also previously defect but brand new DVB-T2 indoor antennas that failed to work until I found and fixed the problem that what was wrong with them. And I examined the circuits that were used. They were also sold on Aliexpress as very large distance amplifiers for indoors. But because they simply never worked in my living room or anywhere else, also because of the ferroconcrete and the HF blocking windows used in my building, I broke open the housing to examine the circuits. Still my original KPN active 5V indoor antennas worked in one spot of my wooden/brick balcony wall but these Taffware named Antennas never did. And if you see next photo it is easy to see why. The coax cables were poorly soldered and the signal wire of the out cable wasn’t even connected. And they also were poorly kept into place by the box the pcb was housed in.
Also the outside shield wiring of the coax was hardly soldered onto the board. Looking at the board marked SAN_AMP_V2.0 it is clear that this time the active component was a HF transistor marked Q1 instead of an IC. The Q1 smd code was AMs as next photo taken with my firmware fixed G600 shows.
Making it an BFP420 transistor that can be used in oscillators upto 10 GHz!
And diode D2 had smd code T4 which makes it likely a simple 1N4148W for providing the 5V DC input.
After I fixed both cheap indoor antennas they finally worked but not better than my good old KPN DVB-T1 active indoor antennas.
And I am almost certain that both my defect outdoor DVB-T2 antennas will work again after I have replaced both U1 ICs with the ordered BGA2851 MMIC chip from NXP. Because this often is the case when no other component fits the bill. And in case the antennas still fail to work afterwards this article hopefully still provides enough information that may be of help in fixing your defect DVB-T2 antennas. Or maybe even better in fixing your also poorly firmware equipped original G600 LCD Microscope too !
Update: After my third new DVB-T2 outdoor antenna was received and tested I could receive DVB-T2 channels again. But because my new outdoor antenna only received the Dutch channels and still not the further away German TV channels it turned out that my outside 75 ohm coax cable was bad. And after the bad coax cable outside was replaced by a brand new cable also my other previously replaced 2 DVB-T2 outdoor antennas worked again!
So the in the meanwhile received BGA2851 MMIC tssop NXP IF amplifier ICs were no longer needed although they probably would work as replacement for the 2HF and 2H5 U1 ICs. But they had another smd code being .MCt. And probably the 3th character in these smd codes only represents where the chip was manufactured. So it is not yet clear what U1 chip exactly was used in these antennas.
See next with my G600 microscope captured last photo of these pin compatible BGA2851 chips.
So in the end nothing needs to be repaired anymore, and only my now perfectly working G600 1 to 600X Portable Rechargeable LCD Microscope desperately needed an upgrade.
I kept looking for that exact same U1 HF amplifier chip with the right smd 2H(5) or 2H(F) code. And after a week or so I unexpectedly found that exact matching component with that code on the webpage of The SMD CODE BOOK.
The 2H* pin compatible chip with SOT363 connections is in fact indeed a low noise 3.5 GHz 5V wide band ABA-52563 RF amplifier ic. And is like the pin compatible BGA2851 used as wide band RF Amplifier but is according to its datasheet also used in all sort of applications. And the tiny tssop chip is also available as 3V ABA-32563 amplifier but in that case with another smd code being 2K*.
I now also found this IC with 2H* code on Aliexpress but 10 of these tiny MMIC ICs cost about 23 Euro/US dollar, which is quite expensive. Luckily they are not needed anymore since all my DVB-T and T2 antennas are fixed and working.
Albert van Bemmelen, Weert, The Netherlands
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