VK4ZXI

Testing a cheap Chinese duplexer as a 70cm DATV DVB-T 7 MHz TX filter- Wow! Introduction In my last post I described a cheap Chinese duplexer re-tuned as 70 cm DATV DVB-T 7 MHz TX filter. The duplexer uses notch cavity filters, six in all. The notch filters have a much sharper edge, compared to a band-pass filter. The sharp notch seems suited to the vertical edges of a DVB-T signal. I initially check the signal source, a HiDes camera with direct DVB-T output at 1080P. I was a little surprised at the spread, but the filter cleaned it up well. This would indicate the need for a filter before the main power amplifier. I pressed on with just one filter and tried it at the output of the amplifier, a 10 W device, from Darko OE7DBH, using a RA60H4047M1 60 W module. Even with the indifferent input, the filter was able to reduce the spread to -60 dB and give a clean 10 W output. The notch duplexer/filter seems to overcome some of the major hurdles with DVB-T amplifiers and warrants ...

My journey in DATV and the future: 4K UHD or internet-linked DATV repeaters; Not that crazy? Draft In this post I want to briefly outline my DATV journey and a quest for Full HD DVB-T. I have achieved this in a relatively short time and out of some of my difficulties, have wondered if first, 4K UHD DATV and, second, network-linked DATV repeaters, are possibly not that distant. In this post I will outline my journey, as the future is path dependent, history matters! In the following two posts I will consider ways to achieve 4K UHD and internet-linked DATV repeaters. My DATV journey: Live Full HD DVB-T Personally, coming late to DATV at the beginning of 2013, with a 40 year break in my amateur radio activities (see my first post), I have not had to put in the extreme effort and expense of either analogue TV or digital TV, particularly over the last decade, such as by the DATV Express team, among many others. Before returning to amateur radio I had spent considerable time and...

HD DVB-T HiDes HV-202E ATEM TV Studio DVB-T DATV all working Finally, I have all the pieces connected for a high-quality, live DVB-T TV studio and TX. My interest has been in establishing a high quality, video and audio, DATV system. This post covers the full working system, albeit small-signal. The details of each of the components are covered in earlier posts. The main components of the system are: HiDes HV-202E, self contained DVB-T TX with HDMI input: http://vk4zxi.blogspot.com.au/2014/07/hides-hv-202e-dvb-t-self-contained.html BlackMagic Designs ATEM TV Studio: http://vk4zxi.blogspot.com.au/2014/06/datv-dvb-t-blackmagic-designs-atem-tv.html High-definition digital SLR and CCTV video cameras: http://vk4zxi.blogspot.com.au/2014/06/dslr-cameras-for-live-tv-not-so-simple.html , http://vk4zxi.blogspot.com.au/2014/06/hd-cctv-cameras-cheap-quality-live.html The front of the operator console. The ATEM TV Studio is PC-based and is mounted in a small stand, just viable behind the...

HiDes HV-202E DVB-T self-contained transmitter: Quality all digital live DATV from DSLR camera at last! The HiDes HV-102E DVB-T self-contained transmitter has arrived at US$660 delivered. I ordered the USB version of this professional HDMI/HD-SDI 4 band (100 MHz - 2.5GHz) DVB-T TX originally, but upgraded to the stand-alone box instead. (see why latter). It works perfectly out of the box and is easily configurable for any modulation or media parameters. I had a good experience with the HiDes DVB-T HD CCTV camera transmitter; see earlier post. As such I thought I would try their HDMI input DVB-T TX. Surprising similar, as will be explained. The impressive specifications per HiDes: There isn't much this box can't do! Any frequency (up to 2.5 GHz!), any band-width, any media modulation parameter. There isn't anything that comes close, at any cost. I set it up on a channel my little 16" TV could receive (by cable with an attenuator) and connected...

DATV DVB-T BlackMagic Design ATEM TV Studio: Proof of concept An objective has been to get high quality video and audio, as well as TV production studio abilities for my DATV DVB-T system. Production studio abilities includes the capacity to switch between multiple live TV cameras, recorded media and overlays, such as my call sign. I originally experimented with software production systems, mainly aimed at network feeds, such as Vidcaster and Open Broadcaster. The commercial Vidcaster software has a virtual camera that can be the input video stream for a HiDes's device, such as the UT-100C via PC2TV. This required a fast PC, a HDMI video capture card from a DSLR camera, the Vidblaster software, the PC2TV software and the UT100C all working properly; a difficult feat many of us have stumbled on. An alternative is to use a hardware production studio. The BlackMagic Design ATEM TV Studio is very suitable and a reasonable price, about $1000, given its capabilities. It is desig...

HiDes CCHDTV camera and DVB-T modulator DC-100 (preliminary) I received a HiDes DC-100 (US$250 for camera, $100 for lens) last week but did not have much time to set it up, other than to verify it works. With a bit more time tonight I have a very nice Full HD image from it. The lighting was bad, but a still a good clear image. The DC-100 transmits both a SD and HD channels as can be seen in the channel list. The camera is running on its default setting of 177 MHz, 6 MHz bandwidth, but over a cable with an attenuator. The image is 1080P 30 FPS. As a result there is some flicker from the 50 Hz lights. I will put up some photos of the device and its internals later. CCHDTV is an emerging standard of DVB-T cameras designed to run on existing coaxial systems in buildings and institutions. The devices all seem to be based on the ITE modulator chips. Google CCHDTV for more information. The DC-100 uses a standard CCTV SDI camera, either 2 or 5 Megapixel, the converts the raw S...