A Quick Look at SAMART Strong Black “Free” DVB-T2 Receiver in Thailand

Thai government has made digital television a priority, so they’ve launched a program to give a 690 Baht voucher ($21) to all households in Thailand. The voucher is send by registered mail to your home, and delivery has to be signed by a Thai person. Then you can go to a shop equipped with a Thai ID card and house registration book copy, present this voucher, and get a free (except for tax payers of course) DVB-T2 receiver, or use it to buy something a more advanced set-top box or digital TV package with 690 Baht discount.

690 Baht Voucher for Digital TV
690 Baht Voucher for Digital TV

We decided to get a free DVB-T2 receiver, and ended up with a box called SAMART Strong Black supporting SD and 1080p video streams over DVB-T2, EPG (Electronic Program Guide), and with a USB port to connect devices for recording programs or time-shifting. SAMART is a Thai company whose name means “can” (formal) as in “we can”, not as in “beer can”… So I decided to have a closer look at the device, and report what kind of features and hardware a $21 DVB-T2 may have.

SAMART Strong Black Specifications & Features

Specifications listed on the user’s manual:

  • Processor – 32-bit RISC processor @ 550 MHz
  • System Memory – 64 MB DDR
  • Storage – 8MB Flash for firmware
  • Video Output – HDMI up to 1080p60 or AV
  • Tuner
    • System – DVB-T2 (ETSI EN 302 755)
    • Receiving Channels – 470 – 862 MHz
    • RF Input/Output Impedance: 75 Ohm
    • Active Antenna – 5V, 150 mA
    • Demodulation – QPSK, 16-QAM, 64-QAM, 256-QAM
    • In and Out Antenna connectors
  • Video Codec – [email protected] and [email protected], MPEG-4 P2 ASP, H.264 MP & HP
  • Video Containers – MKV, AVI, MPG, MP4, TS, DAT, VOB, FLV, MPEG
  • Audio – Codec: MPEG-4 HE-AAC v1/2; Sampling freq: 22.1 kHz, 32 kHz, 44.1 kHz, and 48 kHz
  • USB – 1x USB 2.0 host port
  • Misc – Power LED, IR receiver, 3.5mm jack for IR extension, 4 buttons on front panel (power. vol/ch- +, vol/ch -, and exit/menu)
  • Power Supply – 100-240V 50/60Hz in to 5V/1.2A out
  • Power Consumption – Active: <= 6W, standby: <= 0.5W
  • Dimensions – 175 x 185 x 55 mm
  • Weight – 550 grams

Other features include 3D display support, picture adjustment (color/brightness/contrast), 7-day EPG function, USB hard drive for PVR, time-shifting, and firmware update functions, multiple audio and subtitles, automatic and manual channel scanning and so on.

SAMART Strong Black Unboxing

That’s the pretty package for this DVB-T2 receiver box.

The box comes with HDMI and AV cables, a 5V/1.2A power supply, an IR remote control with two AAA batteries. a warranty card, a user’s manual (strangely in English only), and some promotional brochure.

SAMART_Strong_Black_Package_Content
DVB-T2 Receiver and Accessories

I’m not exactly sure that 5V/1.2A will be able to handle an external 2.5″ HDD, we’ll have to see another day. Let’s have a closer look at the device itself.

SAMART Strong Black (Click to Enlarge)
SAMART Strong Black (Click to Enlarge)

There’s a government sticker on the top of the box to make it clear that box was “sold’ as part of the program. Four buttons are on the front pane: power, Ch+/Vol-, Ch+/Vol+, and Exit/Menu, as well as the power LED, and a window for the IR receiver. The USB port is on the right side of the box. The rear panel comes with the following port from left to right:  RF antenna connector, RF loop, jack for optional IR extension cable, HDMI output, 3.5,mm jack for composite and L/R audio, and power jack.

SAMART Strong Black Board Pictures

There’s a two year warranty with the device, which I may have well lost, since as usual, I open the enclosure. There aren’t any screws, so you have to pull the top of the box with some tools.

SAMART Strong Black PCBA (Click to Enlarge)
SAMART Strong Black PCBA (Click to Enlarge)

The board name is SAMART-G v.1, so it looks like it’s really a locally designed and manufactured product. The processor has a small heatsink on top, but I failed to remove it because the thermal paste would have to be softened with heat, and I don’t have the right equipment for that. But we can still check the other components: ESMT M14D5121632A is a 64GB DDRII RAM, and Mstar MSB1236C must be the demodulator.

Close up on Tuner (Click to Enlarge)
Close up on Tuner (Click to Enlarge)

I’ve also open the shield on top of the tuner to find out the device uses MaxLinear MxL608 tuner, which appears to be quite popular, as over 10 million STBs feature this tuner.

Since I did not have full details about the processor, and the operating systems, I decidd to connect a USB debug board to the 4-pin connector on the board. The left and right are respectively ground and 3.3V pin, so I played with the two other pins, and selected various baud rate, but all I got on my minicom terminal was gibberish.

A Google search for 550 MHz processor used in STBs points to Mstar or Novatek processor, but since neither company list their products lists on their respective website, it’s still unclear which exact processor might be used. I could only find one STB with star 550 MHz processor, and another one with Novatek 550 MHz processor. My guess goes towards Mstar since they’ve used an Mstar demodulator in their design.

We tried it at the shop, and it worked fine, but my indoor antenna at home must be too old, as the signal was 0% even though I live close to the broadcasting antenna. I tried to get a 300 Ohm to 75 Ohm matching adapter to make my own antenna, but I was told they don’t do this in Thailand, it’s old tech. maybe a language problem. So instead I purchased the matching adapter on Ebay, together with a cheap Digital TV indoor antenna.

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onebir
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onebir

Yes beer can!

Alfred Braithewaite
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Alfred Braithewaite

“Digital TV indoor antenna”

There is no such thing as a “digital TV antenna” — all electromagnetic waves are analog.

It is the transmission mode (helpful summary of modulation types at https://en.wikipedia.org/wiki/Modulation) which differs between “analog tv” (vestigial sideband modulation, a type of AM, for video, usually FM for audio) and “digital tv” (COFDM for DVB).

The antenna just picks up the electromagnetic waves and has no awareness of the type of modulation, monochrome or color, picture definition, or whatever.

The important thing is that the antenna is suitable for the frequency of the transmission eg “rabbit ears” style for VHF transmissions, and a mini log periodic or dipole plus reflector for UHF transmissions.

The branding of TV antennas as being “digital” is just a marketing ploy. Some even go so far as to label their antennas as not just “digital” but “HD digital”.

More technical details at

Alfred Braithewaite
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Alfred Braithewaite
ohmohm
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I can’t buy 300 Ohm to 75 Ohm (4:1) matching adaptor in Thailand too. So, I take it from old TV antenna.

In Chiangmai, biloop antenna with reflector should work fine (http://pantip.com/topic/32813757#). It cloud be made DIY easily. One loop has impedance approximately 133 Ohm. Parallel of two loops for half impedance (133/2=66). Connecting to 75 Ohm may work without 4:1 balun matching adaptor but we need 1:1 balun. Just winding coax cable.

Alfred Braithewaite
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Alfred Braithewaite

@cnxsoft

Well looking at the photograph of the antenna which you have bought, it is not something I would have recommended, and would be surprised if it picks up an adequate signal unless in a location of reasonably high signal strength close to the transmitter.

Of course with digital TV, it is the signal to noise ratio which is important, because generally digital tv is an either you get enough signal or your do not, or if just on the borderline (or too many errors due to local electrical interference eg unsuppressed motor) then a pixellated mess.

For UHF signals something like this approaches the best design

http://www.ebay.com/itm/Indoor-TV-Aerial-Antenna-Fully-Flexible-Caravan-Motorhome-Log-Periodic-Digital-/360648671336?pt=UK_ConElec_TVAerials_RL&hash=item53f8560068

and for VHF something with rabbit ears.

A combination of VHF and UHF would be something like this design —

http://www.ebay.com/itm/indoor-Zimmer-Antenne-HAMA-UHF-VHF-FM-Amplified-Antenna-36dB-230V-12

http://www.ebay.com/itm/LUXTRONIC-DT2000-DISH-INDOOR-TV-BOOSTER-ANTENNA-HDTV-COMPATIBLE-VHF-UHF-FM-/381092016152?pt=US_Cable_TV_Boxes&hash=item58badab018

Remember for optimal signal pickup the size of the active dipole needs to be related to the wavelength of the transmission — hence the long rods of rabbit ears for the longer wavelenght VHF and the short “bow tie” style dipole for the shorter wavelength UHF. So a flat rectangular “plate” antenna approximates to neither.

As Scotty the Engineer would says “”Ye cannae change the laws of physics!” even with lots of electronic amplification which often makes things worse.

Of course these indoor antennas are poor substitutes for “proper” fully size antennas which are to be mounted outside or in sometimes where signal is sufficient in the attic/loft space (obviously not where there is a metal roof or where there is lots of metal objects or pipework).

dhead666
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dhead666

I looks like MStar MSD7802 is usually paired with the MStar MSB1236C so I guess it’s the case with this receiver, I have DVD-T2 receiver which got both of the chips (I decided to not solder off the shielding box and checkout the tuner).

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[…] hub with two RF dongles, a USB flash drive, and a webcam, HDMI and Ethernet cables, as well as a DVB-T2 set-top box to the HDMI input port. Boot time takes about 35 seconds. The LCD display ion the front panel shows […]

Murat
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Murat

I bought a mygica dvb-t2 usb stick but I can’t get any signal with bundled very small passive antenna in Bangkok. Did you managed to get signal with indoor antenna in Chaing Mai?

mansor
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mansor

samart strong disposable non malay channel.

tony
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tony

anyone here know where to purchase this item online and able to ship oversea?