Recently, I embarked on an adventure to scan the C-band satellites in the sky. Unfortunately for me, my TBS 6925 tuners are both rather unwell and my Prof Revolution S2 8000’s are not doing much better by showing similar “bursts” of errors on DVB-S2/8PSK transmissions. I thought it was probably time to replace my tuners, since they’ve both based on the ST STV090X tuners which seem to be problematic as they age.
Rather sadly, it seems my only option for a comparable card is to go with a TBS6903 (US$299.99 PCIe dual tuner), TBS6908 (US$399.99 PCIe quad tuner) or TBS5927 (US$229.99 USB single tuner). All three options are based on the STV091X tuners supporting 16/32APSK, MIS, ACM/VCM and CrazyScan features. Unfortunately, for me, they’re also more expensive than my TBS 6925 and I didn’t quite feel like splurging right at this moment.
Instead, I turned my eyes to the TBS 5220SE, which seems to be a rather capable USB tuner. It’s a rather unique multi-standard tuner which supports DVB-S2X/S2/S/T2/T/C2/C and ISDB-T, making it both useful for satellite TV and terrestrial TV across the majority of the world. If I had known about it, I would have probably bought one prior to my trip around Asia. Best of all, for DVB-S/S2/S2X, it supports the APSK modes as well. The only thing missing seems to be DTMB/DMB-T standard support and VCM/ACM support. It’s also noted that ISDB-T wouldn’t be quite that useful in Japan as they also have a conditional access (CA) system on top of it. It would also be one of the first devices supporting DVB-S2X that I’ve come across.
Best of all, it’s USB powered and lists at US$89.99, using an Si2183 tuner for satellite and Si2168 tuner for terrestrial, both of which are supported by CrazyScan. It looks like just what I’m after!
The unit arrived in a slightly crushed cardboard box with a square footprint. It’s pretty interesting to see the colour print and their slogan of “The Best Solutions for Digital TV and More”, even though TBS stands for Shenzhen Turbosight Technology Ltd. The type of tuner is noted on the label as a Multi Standard, with a QR code to lead to the driver software.
The first thing you see upon opening the box is a foam layer with the tuner in it. Conveniently, there are cut-outs for your fingers so you can easily extract the tuner.
The tuner itself is a fairly compact, palm-sized, robust-feeling aluminium-encased unit.
It’s fairly simple, with two LEDs on the front indicating power and tuner lock.
On the rear, there is an F-connector for satellite LNB connection, a PAL type connector for terrestrial aerial connection and a USB 2.0 connection which supplies the power and data. This is about as much as can be fit on the rear of such a small unit, but like many contemporary units, it lacks a loop-out port, precluding easy daisy chaining receivers or spectrum analyzers off the one LNB output.
The underside has a label containing the serial number and MAC address of the unit (in case it is used for one-way satellite data reception).
The only other inclusions in the box are a F-to-PAL adapter, in case you use F-connectors for your terrestrial aerials and a double-headed Y-type USB cable to allow for extra power, similar to early external bus-powered hard drives. The pink connector is power-only, when combined with the power-and-data black connector, it allows for a total of 5V/1A (or 5W maximum power) to be delivered. This seems a little low to operate a satellite tuner, especially since the LNB and switches need to be powered from the tuner, so there could be some difficulties especially for installations needing motor control. However, in the case of simple LNB+switch installations, it could be enough (e.g. 200mA at 18V is 3.6W) and is very convenient.
I downloaded the latest drivers and tools at the time from TBS’s Download area. I tried the unit under Windows 10 on my main workstation, as it’s the one I use most.
Installation was trouble-free on and the unit was immediately recognized.
The driver version was 188.8.131.52, and is signed. It didn’t seem to cause any instabilities – there were no crashes while testing despite trying to lock a number of different sorts of signals.
One of the tools you will definitely need to have is the 5520SE Change Mode Tool.
Then, after a short wait, the tuner can be used under the new mode. Note that the tuner cannot be used simultaneously to receive terrestrial and satellite signals. It can only demodulate one at a time! The two connectors are provided as a convenience to avoid the need of constant cable swapping, as well as due to the fact that the front-end chips are different and that terrestrial antennas are generally unpowered compared with satellite LNBs.
As I rarely use my satellite cards to watch TV directly, I spent most of my time testing the card with CrazyScan and comparing it with the older TBS 6925 (that’s somewhat sick). That being said, the card did work well with ProgDVB as well, with TBS drivers being mostly top-notch for compatibility.
When it comes to satellite, CrazyScan on the TBS 5520SE definitely works, but the RF signal strength values returned have quite low resolution (1dBm steps) resulting in a very “stepped” appearance. The scan is also slightly slower with the same step size setting. For initial testing, I used Optus D2 which I had a good signal from, but unfortunately, does not carry DVB-S2/8PSK nor APSK style services.
For comparison, that’s the same satellite as scanned with the TBS 6925, although slightly differing in time resulting in a slight difference around the feed area of Optus D2 where they come on and off. The trace is much smoother, but to the TBS 5520SE’s credit, the results are quite similar for shape with the TBS 5520SE reporting a higher signal level.
When it came to blind-scan locking, the TBS 5520SE was slightly frustrating, as its blind-scanning was quite slow resulting in the application waiting for a response from the tuner over almost half a minute before giving up in some instances. The tuner could lock most regular services, although had no success with ACM/VCM as expected. It did, however, have difficulty with locking <1000kS/s services as well and returned a “phantom” lock on a non-existent carrier instead.
The comparison from the TBS 6925 – the majority of the remaining carriers are non DVB type, or are not received with enough SNR to lock. Of course, the 6925 is more comprehensive, being the more capable and expensive card, but the 5520SE is not bad.
Just like the Prof 8000 which cannot do ACM/VCM, the I-Q constellation plot does give you a good clue as to the state of the service – in this case, it seems that this link runs both QPSK and 8PSK modes.
In the case of an unlockable service, the tuner sometimes returns a rather strange constellation plot that resembles a very high QAM transmission at an unrealistically high SNR.
Blind-scanning a relatively weak DVB-S/QPSK feed transmission was also successful for lock even where BER rates are too high to successfully watch. This is quite decent performance, similar to that of the TBS 6925.
Moving over to Optus C1/D3, it had no problems handling Optus’ trial transmissions with DVB-S2/8PSK and FEC 9/10 as well as standard Foxtel DVB-S2/8PSK FEC 3/5 transmissions.
There is, however, an issue with BLscan. While it does work, attempting to blind scan regions with no signal results in a very slow time-out, resulting in a very slow BLscan that can take 12 hours or longer. At other times, it can “lock up” mid-way and never recover even when left for some time.
I also found another issue, which is probably limited to a fault in my unit – namely that I couldn’t get any DiSEqC to work. See the next section for my experiments.
Another attraction is being able to use CrazyScan2 on terrestrial signals for the first time.
The same signal strength granularity rears its head here as well. With the AirScan, it is possible to blind scan for DVB-T transmissions – in my new location, this comes mainly from a fill-in.
While successful, it seems on some marginal signals, it can miss out on a carrier. Manually selecting it and forcing a blind-scan works just fine.
However, it seems that if you get the bandwidth wrong (e.g. selecting 8Mhz instead of 7Mhz), the tuner takes so long to decide there is no signal that the program crashes.
At least now, I can get some nice constellation plots for terrestrial signals as well. Signals here are a bit hard to get reliably, but that doesn’t look too bad. A 29dB SNR is a bit low for comfort, but at least I can get some TV.
Teardown & Troubleshooting
Unfortunately, as I did have DiSEqC problems with my unit, I decided to tear it apart and see if I could fix it myself. Postage back to the manufacturer would cost about half the cost of the unit and would take months to turn-around, so I just couldn’t be bothered. It works perfectly fine otherwise.
The first step is to remove the locking nut and washer from the F-connector, thus allowing the inside board to be free of connection to the case.
After that, it’s as simple as removing the two screws on either front or rear panels, taking out the panel and sliding out the PCB.
The PCB is a bright red colour, with this particular PCB dated Week 29 of 2017, version 1.2 (?). There seems to be a provision for an external DC power supply jack, but it was not installed. On the top, there’s a number of 3.3V linear LDO voltage regulators, a number of inductors and solid capacitors for switching converters (with chips on the underside). The main chip on this side is a Silicon Labs Si21832 Dual ISDB-T and DVB-T2/C2/S2/S2X/T/C/S Digital TV Demodulator. The front-end chips are under a soldered-down shield.
The underside has a good number of ICs, including:
- Cypress Semiconductor CY7C68013A EZ-USB FX2LP USB Microcontroller/High-Speed USB Peripheral Controller for USB connectivity
- NXP LVC574A Octal Edge-Triggered D-type Flip-Flops
- NXP 74LVC74AD Dual D-type Flip-Flop with Set and Reset
- TI 545?6 (?)
- T24C02A EEPROM
- 05GA Transistor (?)
- LY Transistor (?)
- AX5201 Step-Up PWM DC-DC Controller
- PZT2222A NPN Bipolar Transistor
- SS14 Schottky Diode
- 24Mhz Oscillator
After some rather harsh desoldering, I managed to get the shield off as well, for a peek underneath.
There are two oscillators – a 24Mhz for the terrestrial side and a 27Mhz for the satellite side. The terrestrial side chip is marked 215730 A00MUN 1653 and the satellite side chip is marked V2018 Q38HC 731D.
As for the DiSEqC issue, I looked at the output power to the LNB in AC coupling with no load. The DiSEqC command was sent with the oscilloscope triggered, and the amplitude of any data is well below the expected level of about 0.65V, being closer to 0.15V.
This is shown with the power routed through an external DC-blocker. In-between DiSEqC bursts, the unit issues a constant 22khz tone – this may be a peculiarity with my CrazyScan LNB configuration.
I traced the board to find that the signal before D2 (Schottky Diode) seemed just fine, but after the diode, the amplitude was severely reduced. I tried replacing the diode to no effect – the diode itself was just fine. I tried examining for shorts, but couldn’t find any. Due to the multi-layered construction of the board, I couldn’t exactly follow the traces inside, but ultimately, I never ended up fixing the problem. Oh well. At least I didn’t make it any worse.
The TBS 5520SE is a rather inexpensive unit that is rather interesting. It’s capable of decoding almost all standards used for digital television in both terrestrial and satellite forms (with the exception of DTMB/DMB-T) and is rather inexpensive, as well as being USB bus powered. This is a unique combination that makes it quite a good unit for travellers, but also equally appealing to those who “just want a tuner”. The drivers work well and the CrazyScan/CrazyScan2 support makes the tuner valuable for diagnosing signal problems and aligning antennas.
It does have a few downsides, notably a lack of support for ACM/VCM signals, slow time-out in case of a non-existent or unlockable signal, limited signal strength granularity, lack of a loop-out port and limited LNB power due to USB power constraints. In the case of my unit, it seems that DiSEqC is not functional either. However, given the price, it’s still very attractive and the support for DVB-C/C2 and DVB-S2X could also prove useful in some cases.
Sadly, it’s no replacement for a TBS 6925, but it’s still a pretty handy unit to have around. I definitely like mine!