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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Parasuraman S
August 12, 2022 at 9:32 pm
My head is reeling! Such an intricate job with minute explanations!
AdamS
August 12, 2022 at 10:04 pm
Great work, but it seems that the key thing to learn from this article is not to buy cheap rubbish on AliExpress!
Albert van Bemmelen
August 14, 2022 at 12:39 am
You are right. And if I hadn't found that perfect firmware upgrade I never would have enjoyed using my G600 LCD microscope. And I would have ended up with a cheaper but useless product. Still good products are also made in China like the RT809H that I needed to reflash my G600 eeprom with. My GQ4x4, my G540, my Xeltek SP-L, my TL866I & II, they all couldn't read and write to the for them unknown algoritm eeprom chip. And only the GQ4x4 is also capable in only writing to parts of most (e)eproms. Because the other universal programmers are incapable in writing to only a specific part in their memory. Which I am almost sure also the RT809H is capable of but haven't tested yet. Which I noticed when I wanted to write into just a specific part of an 27512 eprom memory with the firmware content of a 27256 eprom for my fixed Commodore 1571 floppydrive.
John Runng
August 13, 2022 at 3:22 am
Thank you for information on SMD Code Book. You gave my hobby a big Boost. Coincidently I was Troubleshooting that same exact SAM AMP preamp and got stumped because I couldn't determine the chip. I thought it was a JFet. This is your best article yet.
Albert van Bemmelen
August 14, 2022 at 12:20 am
Glad that the article helped you John! Those 2000 miles DVB-T2 indoor wall antennas, Taffware or how they are marketed, are in my opinion just rather big flat insensitive antennas compared to my much smaller indoor Dutch KPN antenna. And the fact that they also need an external 5V USB voltage instead simply getting 5V over the coax cable makes using them worse.
Waleed Rishmawi
August 13, 2022 at 2:18 pm
a little bit confusing for me when mixing two repairs in one article but the information you provided were amazing. Ali express is the worst source of buying microscopes... I bought mine from the states, alot more expensive but never gave me a headace..lol have a blessed day
Albert van Bemmelen
August 14, 2022 at 12:06 am
Indeed buying on Aliexpress often gives little warranty in case of receiving bad products. And in China 1 year is all a buyer gets, which in Europe is 2 years. But even getting one year for foreign buyers is questionable when the Aliexpress buyer protection time period is only about 15 days after the product was received. And most problem sellers only refund the already paid in advance money after we also pay for the shipping cost to return the goods which is way too expensive. And in the past sellers even sold products that were already damaged because of a very poorly packed touchscreen needed for fixing an Android tablet that was cracked in transport. And he refused to refund afterwards for the already damaged parcel blaming me for damaging his useless product. Have a blessed day too Waleed!
Paris Azis
August 13, 2022 at 6:58 pm
A “two in one” kind of repair...Complicated a bit, but nicely presented. Good job, Albert!
Albert van Bemmelen
August 14, 2022 at 3:23 pm
It's a bit like ...one for the money, two for the show
Three to get ready, now go, cat, go. (I hope I won't get sued for stealing someones music now... lol)
Anwar Shiekh
August 15, 2022 at 12:45 am
Would have been nice to have separated the two repairs as separate articles
Albert van Bemmelen
August 17, 2022 at 10:04 pm
Yes true, but the articles were made in one go as they happened. And are as you could see related. I even could have made 3 different repairs. One about the G600 LCD Microscope, one about the outside antennas, and one about the inside Taffware repair. But they all did fit in one.
Mikael Hansen
August 17, 2022 at 6:55 am
Why not stay with the old fashioned passive TV antennas?
No build in amplifiers that need power supply.
And DVB-T (and T2) uses the same frequencies as analogue TV did, so there is no need for a new type of antenna.
Albert van Bemmelen
August 17, 2022 at 9:55 pm
You could try if those work although polarization will be different. Probably now Vertical instead of horizontal. I tried the two I had but they just didn't work at all. Plus my amplified outside antennes have extra 4G/LTE filters in them.
Ahmet
August 19, 2022 at 10:16 am
Hi, I am looking for someone who can repair my faulty Gimbal for smartphone
Ahmet
August 19, 2022 at 10:17 am
Location in Malaysia
Yogesh Panchal
August 19, 2022 at 6:39 pm
Good JOB! Albert,
Now a days HD Microscope cameras available which can be connected to BIG Screen TV with HDMI / VGA port.
Albert van Bemmelen
August 21, 2022 at 12:41 am
Yes, they sell others too like stereomicroscopes like my shopowner was very happy with. But I am quite happy with my new firmware fixed G600 LCD microscope and my older Traveler USB microscope.