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Portsdown DATV
Amateur TV GB3HV

 


 

The Portsdown
Digital Amateur Television Project


The Portsdown DATV project provides an easy way to “get on air” with Digital ATV at relatively low cost. The Portsdown system enables amateur radio operators with little or no
knowledge of Digital ATV to construct the hardware elements,load and configure the software and use the system to send live Digital ATV signals across town on their existing aerials. It
includes the new Reduced Bandwidth modes and the ability to receive and transmit to local repeaters using the more traditional 2 and 4 Msymbol DATV modes.
 

  • Symbol rates to include the Reduced Bandwidth (RB-TV) modes and “normal”  DATV modes
     

  • Frequency coverage of 146 MHz, 437 MHz and 1.2 GHz bands
     

  • Cost-effective stand-alone (not PC based) Digital TV Transmit solution
     

  • Analogue video input to allow use of camcorders and mixing desks
     

  • Use of commonly available components and modules
     

  • Modular construction enabling a step-by-step system build and easy trouble-shooting
     

  • Designed to encourage home construction
     

  • Fully documented and supported including easy software
    installation and upgrades

  • Flexible receive solution based around readily available
    software and hardware
     

At the heart of the Portsdown transmitter is a Raspberry Pi 3 (RPi) computer running a BATC
customised version of the F5OEO rpidatv software. The RPi 3 was chosen because it is relatively low cost, has an on-board MPEG-4 (H264) encoder and versatile hardware interface
(GPIO) capabilities. The system is controlled using a simple touch screen interface; no keyboard, mouse or monitor are required. If the touch screen is not available, the system can
be controlled using an external PC connected over a wired or wi-fi network.

The Portsdown filter modulator board is available as a ready built unit or a blank PCB from the BATC shop. The Portsdown RPi software is capable of controlling an external ADF4351 synthesizer module to give outputs on 146 MHz, 437MHz and 1.2 GHz amateur bands.
Just like any other DATV transmitter, the Portsdown has a relatively low output power (10 milliwatts maximum) and will need bandpass filters and drivers / amplifiers on the output - there’s lot of designs around for sale or easy home construction and more details can be
found on the BATC wiki.The Portsdown receiver is based around the Tutioune receive software
from F6DZP and the BATC USB minituner hardware project. Components are available from the BATC shop, including the new tuner module from Serit which enables continuous coverage from 146 to 2650 MHz without the need for external receive converters.

The Portsdown project aims to condense many recent RB-TV and DATV initiatives into one, easy-to-build and geton-air project. It brings DATV and RB-TV within the grasp of the average ATV operator who still values some basic hands-on construction and is looking for a project which will deliver the capability to operate on all the commonly used DATV and RB-TV modes at a reasonable cost.



Portsdown ATV Transmitter Specifications

Frequency coverage: 140 - 1325 MHz

DATV Modes: DVB-S QPSK at 1/2, 2/3. 3/4, 5/6 and 7/8 FEC

Symbol rate: 125 Ks to 4 Msymbols

Typical RF output: +10dBm @ 146 and 437 Mhz, +6dBm @ 1255 Mhz

Typical MER (with LO filters): 26db measured with Tutioune Version 5

Video input: Rapberry Pi camera, Analogue input via EasyCap USB device

Video Encoding: MPEG-2 and H264

Audio input: Via USB audio capture device

Control: LCD touchscreen or console menu via SSH


Receiving Portsdown Digital ATV

To be able to receive Portsdown Digital ATV a Satellite receiver is used.
The most economical Satellite Reciver to use is the FreeSat V7 Comba which is for sale on Ebay for around $55 - $70.


The FreeSat V7 Combo Satellite Receiver

1080P Full HD DVB-S2+DVB-T2.
Support USB PVR Ready and USB wifi to Network Sharing.
Support Full speed USB 3G dongle.
Support YouTube via USB Wifi dongle.

Specifications:
Plug Type:US, EU
Standard: DVB-S/S2;DVB-T/T2 Complian  
RF Modulator:PAL/BG(209.00MHZ/11CH)  
Power Supply:Input DC 12V/2A  
Video Decode: AC-3,MPEG-2 MP@HL;H.264 BP MP&HP@L4.1  
PAL/NTSC:Automatic PAL/NTSC conversion  
Channels Number:6000 channels TV and Radio programmable  
OSD Language:English German French Portuguese Spanish Italian Russian Turkish Polish Arabic Farsi  
Picture: JPEG,BMP,PNG,GIF Supported  
OSD Color:16-bit OSD with anti-flickering  
Save Channel :Automatic save for last channel
 


Test Screen using Portsdown
 


Controlling Software

 

 

 Westlakes Club News  VK2ATZ broadcast Sunday's 9.00hrs on the VK2RTZ Repeater on 146.775MHz
Westlakes Amateur Radio Club Inc. York Street, Teralba NSW