VK4ZXI

Digital Video Processing with HD CCTV: Noise reduction In this post I examine some of the sophisticated technology used in digital high definition CCTV cameras, including a the powerful underlying SOC electronics, and the similarities with audio noise reduction in audio, as used in amateur radio. Noise reduction in HD CCTV I read very widely and like to see or create connections between apparently disparate ideas and technologies. From an earlier post on working with a Pentax lens I have, I read about the image processing abilities of some Pentax lenses.   Pentax/Richo have an award-winning image processing system, PENTAX Atmospheric Interference Reduction (PAIR). http://www.ricoh.com/fa_security/security/pair/  The results are amazing:       From a first reading, the processing seems to be done in the lens itself, something that had me mystified as to how such spectacular results are possible with just optics. However, on closer reading, th...

BlackMagic Design ATEM TV Studio problems with 1080p; a hardware limitation? In this post, I think I have discovered the problem of the ATEM TV Studio not accepting 1080p input, a hardware limitation. Alternatives are then considered. BlackMagic Design ATEM TV Studio As noted in earlier posts, I use BlackMagic Design ATEM TV Studio as the main component of my DATV studio to connect multiple cameras and other video sources. Overall it performs brilliantly well allowing for most features needed in a professional TV switcher, and with nothing else even remotely in the price range; $1000. http://vk4zxi.blogspot.com.au/2014/06/datv-dvb-t-blackmagic-designs-atem-tv.html     No 1080p input, despite being common format for cameras However, it has one very annoying problem, it will only accept 1080i input, not 1080p, which to a point is reasonable as 1080i is the highest resolution for broadcast TV. The big problem is that almost all cameras...

Achieving 4K UHD DATV- very draft Perhaps a little early, but 4K DATV may be more achievable than I first thought. It would be a bit of a technological coup if amateur radio can do 4K before regular free-to-air broadcast TV. 4K video cameras and monitors are already relatively inexpensive. 4K TV capture/switchers are available and not too expensive. The missing link are modulators, transmitters and receivers, but may be possible using inexpensive SDR TRX; they can already do DVB-T/S. As far as I am aware, broadcast TV is still struggling with Full HD digital TV in some countries, notably the USA with a very large number of small TV stations and the not insignificant cost of having to replace virtually everything, other than their antenna. I suspect the same across some of Europe and Asia. For both terrestrial and satellite, while they may have digital TV, most of it is SD (standard definition) or HD (high definition 720p), rather than wide-screen Full HD (1080i; wish it was 1080p...

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...

  Converting CCTV lens from video auto iris to DC auto iris Summary It seems relatively easy to convert a video auto iris CCTV lens to DC auto iris and for a modern camera to control the lens correctly. I was able to convert a sophisticated expensive CCTV lens to DC auto iris, which otherwise was unusable.    However, I give no guarantee that it will work with any other lens, although I think the principle is the same.   If camera control is not possible or desired, it is possible to at least open the lens's iris with a voltage through a series resistor applied to the drive motor with the correct polarity. The problem I had bought a Pentax motorised zoom and focus lens for use in my amateur TV studio with the idea of using it on a remote-controlled tripod as part of a one person operation. Motorised lens are not cheap ($600), but I bought a new, but old stock, lens cheap (<$100).   The main problem was that the lens used video...

DIY aluminium washers for cavity resonator In many cavity resonators, the input and output coils are rotatable to adjust the degree of coupling and/or transmission losses. Most mount the coaxial connector for the coil on a large washer, so it can rotate, then use screws to hold it in position. Sounds so easy, but where do you get the washers?? After wasting a few hours in off-line shopping at bolt and plumbing shops, I found that I would have to make them. Working with thin metal sheet is usually not easy. However, I devised a simple technique to quickly make them. Any metal that can be cut by a hole saw or step drill could be used, aluminium, brass, copper, even thin steel, (per my post on using galvanised steel buckets) The photo shows the process. Using the hole saw, cut the first blank. Subsequent blanks are started with the sheet over the hole in the wood made by the first and drilling from underneath (hands away from hole), then cutting the blank from above. Use thr...

Cheap GPS-disciplined 10 MHz oscillator- updated 5/10/2014 This post is for a c heap GPS-disciplined 10 MHz oscillator . It is a work in progress, while the links are still active; life is a work in progress... I had earlier set up a Trimble reference, but they are a bit stone-age , but work well! http://vk4zxi.blogspot.com.au/2014/02/gps-disciplined-clockoscillator.html . Modern Trimble gear is too expensive for my purposes.   Update 5/10/2014: I have the device described here now and it works well, especially the little active antenna, I can get satellites though our tile roof. There is a temperature controlled crystal oven version available. It can access most other GPS satellite systems as well as the USA system.  ($70) TXCO version: UBLOX NEO-M8N GPS GNSS receiver board with SMA: http://www.csgshop.com/product.php?id_product=170 The datasheet for the NEO-M8N: http://www.u-blox.com/images/downloads/Product_Docs/NEO-M8_DataSheet_(UBX-13003366).pd...

Homebrew cavity resonator/duplexer for 2m repeater There has been some interest in the club establishing another 2m repeater, but lacked a duplexer. A couple of old cavity resonators were discovered in the back shed. We were able to tune these very quickly and easily using the new Chinese KC901H network analyser (more about that in another post). Why and how they work: an antenna in a box! Up to that point I had heard of cavity resonators but had little idea of how they worked or how they were made. Similarly, so was my knowledge of repeater. However, as I started to learn about them, I became quite intrigued with the technical finesse of being able to transmit and receive with the same antenna simultaneously, albeit on different frequencies. Further, as desirable repeater sites are restricted in number, many repeaters share the same site, again on different frequencies and bands. The solution to the repeater problems is in using very selective band-pass and/o...

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...

BladeRF XB-200 transverter working with SDR# on Windows Software to support the BladeRF XB-200 transverter is beginning to emerge, however, the information is spread across a number of sources. In this post I have amalgamated the various bits of information to get the devices working on Windows 8.1. Connecting the cables It is not entirely obvious how the various connectors are used. The information is provided in the BladeRF GitHub:   https://github.com/Nuand/bladeRF/wiki/Getting-Started:-XB200-Transverter-Board For RX only: RXFILT-ANT to RXFILT to bridge "custom" filter. RXIF on transverter to BladeRF RX to connect transverter to BladeRF. Connect antenna to transverter RXANT for use with VHF and above. Connect HF antenna to ADC (be careful, see earlier post- http://vk4zxi.blogspot.com.au/2014/03/bladerf-transverter-and-hf-trx-its-been.html ). Windows SDR# software for BladeRF  SDR# software to support the BladeRF and Transverter is av...