Amateur Digital Television & The Holy Grail

• New Mexico DTV User Group

• October 16, 2014

Presented by: Ray Bahm & Jim Gale

The Holy Grail

How much do you want it?

What will it cost?

DC Power +9VDC-+15 VDC

Status LEDsRF Out 100 MHz- 2.45 GHz

+12 dBm max.

SMA Connector

(Fe)

USB-2 Data In from PC DATV EXPRESS BOARD

Electrical Details:

Required Computer components

Host computer with at least (2) USB2 I/O ports available for DATV-Express

USB interface cable – USB type “A” connector at computer end, USB type “B” connector at DATV-Express end.

Software support requirements – for DVB-S, Pentium 4 running 2.4 GHz or better, 2GB available hard drive

– for DVB-T narrow bandwidths (2 & 3 MHz), dual-core CPU running 2.0 GHz should be adequate – for DVB-T 2K mode to use all of the bandwidths, the CPU needs to be a quad-core

i7

Operating system - 32 bit or 64 bit Ubuntu (Linux) – Version 14.04 LTS (or 12.04 LTS). Download at www.ubuntu.com/download

Hardware video capture card – Hauppauge external USB models HVR-1950, HVR-1900, PVR-USB2

– Hauppauge internal PCI-card models PVR-150, PVR-250, PVR-350, PCR-500

Hauppage HVR-1950

Symbol Rate(MSymbols/sec)

Select SR from 1.00 to 9.99 in 0.01steps. (Design is optimized for 2-6 MS/sec). There are 12 preset

configurable combinations.

Note: Symbol rates >8.00MS/sec show increased 12MHz sidebands on each side and 35 dB down from center carrier because I/Q low pass anti-

aliasing filters are optimized for 2-6 MS/sec. Below 1.5 MS/sec there could be some undesired aliases spurs (also +/- 12 MHz which is the Nyquist

sampling frequency), if an interdigital bandpass filter is not used . Video displays will appear to be normal in either case.

Signal quality data

EVM (Error Vector Magnitude) -

2.4%.

(Measured with Agilent EXA

N9010A Signal analyzer – software

VSA 89600B).

(≤3% is acceptable for commercial

broadcast).

EVM is the percentage away from the ideal symbol landing spot in the signal constellation. This data is normally measured at the receiver and

takes into account the combined effects of transmitter and receiver Carrier or Signal to Noise ratios (CNR or SNR).

EVM (Error Vector Magnitude)

MER (Modulation Error Ratio) -

32dB.

Minimum recommended down stream MER = 12-13dB for QPSK and 27dB for 64QAM including 3-4dB headroom for reliability. It’s calculated as:

10LOG (average symbol power / average error power).

Video

Determined by capture card specs. Hauppauge model HVR1950 will accept 1V P-P 75 ohm NTSC or PAL

Audio – Determined by capture card selection. Compression: MPEG1

Fig 1 - Block Diagram of DVB-S Transmitter for D-ATV

DTV Express MODULATOR Block Diagram

Item Description Manufacturer Model Cost Est Low end Cost Est High end

1 MPEG Encoder BoardSR-Systems MPEG Encoder $290 $360

2 1.2 GHz FEC & IQ Modulator for DVB-S SR-Systems

DVB-S 1xTS MiniMOD$470 $540

3 First RF amp ?? (about 50 mW) $25 $50

4 RF Power Amplifier 30W (very linear)

Down East Microwave

Part Number 2330PA $240 $240

TOTAL $1,025 $1,190

Table 1 - Cost Estimate of DVB-S Transmitter

SR Systems Mini-Mod 2

The MidiMod2 is a small and compact modulator for DVB-S, -S2, -C, -T (2k and 8k mode) or 8VSB. Duo-DVB-C and Duo-DVB-T are also possible. Owing to the I/Q modulator, the signal output is modulated directly on transmission frequency. To build up a complete digital video transmitter with one or two video channels, you only have to connect one (or 2) MPEG2 encoder(s) to the transport stream inputs and, if necessary, a power amplifier to the SMA output.

SR Systems Mini-Mod 2

SR Systems MPEG-2 Encoder

The module encodes an analogue video and audio signal and outputs an MPEG2 transport stream. The encoder is based on the Fujitsu MPEG2 system chip MB86391, a DSP especially developed for real time video compression. The encoder board includes all necessary peripheral components like SDRAMs, audio and video codecs as well as all required power supplies (3,3 and 1,8 V).

The encoder supports the formats SIF (352×288 Pixel), HD1 (352×576 Pixel) and D1 (720×576 Pixel) with netto data rates from 0,5 Mbit/s to 15 Mbit/s. A 20 bit stereo audio channel is already included in this data rate.

SR Systems MPEG-2 Encoder

The encoder board outputs a transport stream (SPI)according to ISO/IEC 13818 to a 8 bit wide TS inter face with clock and frame sync signal.

The video input can be chosen from CVBS and Y/C (S-video). Available optionally: a parallel input according to ITU-656.

Please note: Booting the encoder needs an additional circuit board; all our modulators and multiplexers are able to do so. The encoder cannot be operated autonomously.

SR Systems MPEG-2 Encoder

SR Systems H264-Encoder

The new H.264 Encoder is designed for the transmission of high-resolution picture data, especially for HD-TV applications. The encoder is extremely economical with 3 W power consumption at the maximum.

Supported formats are HD (1920×1080px) and SD (PAL, NTSC) with netto data rates from 1,5 Mbit/s to 31 Mbit/s.

Included in this data rate is a stereo audio channel between 32kbit and 384kbit.

The encoder board outputs a transport stream to a 8 bit wide TS interface with clock and frame sync signal.

The video input can be chosen between YPbPr, CVBS and HDMI; the picture resolution is up to 1080p@60Hz. The H.264 encoder can be operated autonomously.

Power supply is 5V.

SR Systems H264-Encoder (MPEG-4)

Down East Microwave 1.270 -1.300 MHz Pre-Amp

Frequency range: 1270 to 1300 MHz.

Power Out (linear): 30 Watts minimum

Power Out (saturated): >40 Watts typical

Power Input for rated power out: 50 mW typical, 75 mW saturated. Optional input attenuator available.

Power requirements: 13.5 volts dc @ 10.0 amperes MAX.

Connectors: Type-N female

Size with connectors: 5.5" L x 5.5" W x 4.2" H

Active device: Hybrid RA18H1213G

$245

Down East Microwave (Live Oak, FL)

Model PATV-2330

30 Watt Linear Amplifier

Planning a DIGITAL ATV STATION

• Ken W6HH6 Robbie KB6CJZ

• Orange County Amateur Radio Club - June 2009

What Band Should I plan for D-ATV?Robbie explained that the view of ham radio bands for ATV and D-ATV in Southern California looks like this:•440 MHz - very crowded - looks like a difficult band for D-ATV, but RF amps are cheaper•920 MHz - presents a tight fit for D-ATV, plus lots of noise from “part 15” devices.•1,200 MHz - more room for simplex D-ATV, probably no room for a D-ATV repeater-pair. RF amplifiers get more expensive.•2,400 MHz - RF amplifiers get even more ex pensive. But, probably has room for a D-ATV repeater.

The decision we made is to plan for ham home/portable transmitters on the 1.2 GHz band as a good compromise. Later if we can put up a D-ATV repeater...the repeater

will output on 2.4 GHz.

The MiniMod board and will produce about 1 mWatt RF output. I will need a small RF amplifier to get that power up to about

25 mWatts to drive the 10 Watt RF. All Digital RF modulations require very linear Class A power amplifiers. We plan to run a 30W 1.2 GHz linear amp at about 10 watts or so. Note that the SR-Systems datasheets caution that the RF output of the MiniMod board is UNFILTERED. Stefan-DG8FAC of SR-Sys explained this note means that we need to suppress the 2nd harmonic and the third

Harmonic a little. Following the Modulator Board with two

1.2 GHz Amps provided the required harmonic suppression. The DVB-S D-ATV signal will be about 2 MHz wide.

Alternative 5 - Using a Satellite DVB-S STB

Our first approach to receiving DVB-S transmissions uses a DVB-S satellite box (commonly called Free-To-Air or FTA). A “composite RF” output from the STB can go straight into an old analog TV set. The frequency range of the DVB-S STB tuner range for satellites will include the 1.2 GHz ham band, so no down-converter is needed. The Viewsat VS2000 Xtreme is an example of a DVB-S FTA STB that can be purchased new for about $100.

The Digital ATV Receive System

• Yagi Antenna

• LNB (Low Noise Amplifier/ Block Down-Converter

• Low Loss Coaxial Cable

• Power Inserter (to power the LNB)

• DVB-S Satellite Receiver (with Composite & SVideo Outputs)

• CRT Analog Television with Composite & Svideo Inputs

Amateur Digital Television & The Holy Grail

• New Mexico DTV User Group

• October 16, 2014

Presented by: Ray Bahm & Jim Gale

THANK YOU !