The hardware required to add video to digital voice
Hardware Setup for FreeDV plus Video in Two Easy StepsClick the link below to open the legacy hardware setup page (recommended for older PC's with limited processor capability -- requires an additional USB sound card).
Legacy hardware setup page
When a higher-performance PC is available, the Video TX, FreeDV, and Video RX software are installed on the same PC. Otherwise, two PC's are used: one for Video TX/FreeDV, and the other for Video RX (as shown in the diagram below).
You might want to set up and operate with digital voice first before adding video. Connect the hardware as shown in the diagram below. See the "Software" page for the software required to run FreeDV plus Video.
Step 1: Setup for FreeDV Digital Voice (without Video)
HF Transceiver: You'll need an HF transceiver with 3.5 kHz TX and RX bandwidth minimum, 1 Hz frequency resolution, and independent TX and RX tuning. The author uses an Apache Labs ANAN-10E SDR transceiver. Click on the links below for NU9N's lists of transceivers, most of which have bandwidth and frequency resolution suitable for FreeDV plus Video. However, the intermodulation distortion (IMD) specs for most HF transceivers make them unsuitable for use with FreeDV plus Video, as splatter will affect adjacent frequencies.
Splatter on adjacent frequencies can be greatly reduced by using an HF transceiver with a Class-A output amplifier. There are several Yaesu transceivers with this option (FT-1000MP Mark-V Field, FTdx9000 Contest, FTdx9000D, and FTdx9000MP). However, if an external linear amplifier is used, the IMD (and splatter) will increase.
A technology, new to amateur radio, called adaptive predistortion, can also be used to reduce the overall IMD (by 20 dB or more, including an external linear amplifier, if used). Adaptive predistortion is incorporated into the Apache Labs ANAN-10E SDR transceiver (see link below). For more information on adaptive predistortion, see the "PureSignal" and "Technical" pages (links at the top of this page).
NU9N HF Transceiver Link 1 - - NU9N HF Transceiver Link 2 - - ANAN-10E Link
Sound Card Interface: The author uses a sound card interface similar to the W1ZE design described in the May 2007 issue of the Yavapai Signal newsletter, pp. 10-11. Substitute Triad TY-145P transformers (Jameco P/N 630459) for the Radio Shack units specified in the article. A VOX-operated sound card interface cannot be used with FreeDV plus Video, unless the VOX feature is disabled (the TXfftCO5L application provides an output from the sound card regardless of PTT status). Click on the link below for the W1ZE article, and go to pp. 10-11.
W1ZE Article Link
USB-to-Serial Cable: Required if the sound card interface uses a serial port for TX/RX (PTT) control, and if the Video TX/FreeDV PC has no serial port (connects between the sound card interface and the PC or hub USB port for TX/RX control). The author has used a Gigaware cable (Radio Shack P/N 26-949) with good results. Many amateurs report better performance with USB-to-Serial cables using the FTDI chipset (instead of the Prolific chipset).
USB Sound Card: The author uses a Manhattan Model 151429 USB sound card. A USB sound card with an "input monitoring" feature (such as the Turtle Beach Amigo II) can be used, but will allow undecoded receiver audio to appear at the speakers along with the decoded FreeDV audio (adding noise to the decoded FreeDV audio).
USB Hub: A USB hub is not required if the Video TX/FreeDV PC has 2 or more USB ports. The author has used an older Belkin FSU237 USB hub with good results.
Amplified Speakers: The author uses amplified speakers similar to Cyber Acoustics CA-2014RB speakers
Computer Mic: Almost any electret computer mic will be suitable. The author uses a mic similar to the Cyber Acoustics CVL-1064RB.
Laptop PC: When a higher-performance PC is available, the Video TX, FreeDV, and Video RX software are installed on the same PC. Otherwise, two PC's are used: one for Video TX/FreeDV, and the other for Video RX. A clock speed of 2 GHz or greater is recommended. The author uses an HP 8540w laptop running Windows 7.
Step 2: Setup for FreeDV plus Video (video added to FreeDV)USB Webcam: The author uses the built-in camera on his HP8540w laptop PC (an older Logitech E3560 webcam has also been used with good results).
Laptop PC: If separate PC's are required, the second PC will be used for Video RX. A clock speed of 1.5 GHz or greater is recommended. The author used an Acer Aspire 5516, running Windows Vista, before acquiring his HP8540w laptop.
- 5 July 2013 -
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