VK4ZXI

  Rigol RSA-3015N 9kHz TO 1.5GHz REAL-TIME spectrum analyser WITH VNA https://emona.com.au/products/electronic-test-measure/rf-test-equipment/rsa-3015n.html GCARS repeater UHF Band Pass / Band Reject Duplexer for CB repeaters https://www.rfi.com.au/core/media/media.nl?id=3987315&c=3389566&h=7HxM371SKCIoQI4SUAQLjS9xWxD_rP8Cc1u2S02y8vj3Fszl Understanding Hybrid-Filter Transmitter Combiners https://emrcorp.com/understanding-hybrid-filter-transmitter-combiners/ https://emrcorp.com/wp-content/uploads/2022/07/EMR-hybrid-combiner-manual.pdf RFI Hybrid Coupler, 4 Port ,3dB 380-550MHz ,200W; N(F) https://www.rfi.com.au/SP3855-2203-11 https://www.repeater-builder.com/antenna/ant-sys-index.html#combiner RFI Single Circulator 440-480MHz; Symmetry, N(F) https://www.rfi.com.au/SP4448-3100-11 Ferrite Isolators or Circulators Characteristics and Uses https://www.youtube.com/watch?v=-J8eDdwHf-0 LNA for use with splitters https://www.minikits.com.au/electronic-kits/rf-amplifiers/rf-low-noise...

  Why otherwise good HDMI cables won't always work with modern devices and how to test them. A friend had trouble connecting a modern 4K TV streaming dongle, Chromecast with Google TV, to an older 4K TV. The problem lay with the HDMI cable. It had worked with the previous device, a DVD player, I think, but not the newer 4K dongle. I was mystified by how the cable did not work, so chased it up. HDMI cables are very high-tech and work at very high data rates and bandwidths. As such, the possible length of a cable has always been an issue, something I discovered trying to run long leads to home cinema projectors. The physical construction of the cable has a big impact on the data rate it can handle. Like network cables, HDMI cables use shielded twisted pairs of wires, including a shield ground for each pair. There are three signal pairs and a clock pair. As well there are other wires for digital control signals. There are, or should be, nineteen wires in total. The HDMI standard has b...

  To access movies and TV shows. 1 Need USA VPN to access blocked torrent sites. Either expressvpn or nordvpn. Nordvpn is best for UK TV. They are both about $100 per year. You can use them for streaming. However, you can use a free one just to access torrent sites. 2 Install utorrent.  3 Check the torrent sites Magnetdl (check movies or the shows for the latest or search for old ones), YTS and Torrentgallery for current movies. 4 Click the Magnet link to download the file. Utorrent handles it auto. Files are in downloads. If you move the file while utorrent is running, right-click in utorrent and click "remove" to cut file link to utorrent. 5 Plex is an excellent way to access stored movies. But it takes a bit of setting up. There are Plex apps on all streaming boxes that can be linked to Plex on your own computer. Just run the Plex server program. There are lots of tutorials for Plex on the web. 6 Without Plex, just click on the file using file explorer. 7 If you have probl...

 Transients and dynamics in power supplies for SSB or CW transceivers How to estimate control loop bandwidth from the transient response time? https://www.youtube.com/watch?v=6CdA40ixBkA Richtek Load Transient Tool RD0004 is available at Element14 for about $50. https://www.richtek.com/en/Design%20Support/Reference%20Design/RD0004?utm_source=Social&utm_medium=Youtube&utm_campaign=Video025

Starlink Satellite Internet Gold Coast Queensland Australia My Starlink satellite internet order arrived a couple of days ago, February 2022, after a wait of about nine months. I think the wait was due to my location being serviced by Starlink. I set it up in the driveway temporarily and it worked very well, up to 250 Mb/s downloads. The antenna is now installed with a view of the sky above the house roof and connected as the main internet, replacing the slow NBN FTTN (Fibre to the node, VDSL). Cost The cost in Australia is about $800 for the hardware, then $139 per month. The monthly cost is reasonable given that we pay $100 for Telstra NBN FTTN. I will continue the NBN for a month or so, to make sure the Skylink is reliable enough. Mounting The Skylink antenna needs a clear view of the sky as the low earth orbit satellites can be anywhere in the sky. While the antenna is a circle and looks like a dish, it is made up of about 1000 small electronically steerable antennas using beamform...

  A description of the RX888 Mk II in the I/O group for the devices (join if interested) https://groups.io/g/NextGenSDRs/message/431 How to set up and use an RX888 MkI or II https://drive.google.com/file/d/1KvtYzBKuLva9Ha0x0S67w59G_Nu8qDeC/view Location of latest libraries to use with HDSDR or earlier versions of SDR#. https://github.com/ik1xpv/ExtIO_sddc SDR Console needs release 27 or higher for the MK II. Not available at 2/3/2021.

 Low-cost duplexer for 6m, 2m or 70cm I am proposing a conceptual design for a low-cost, home-made duplexer for 6m, 2m, or 70 cm. I have not built one to this design but it combines ideas from duplexers I have made or from commercial duplexers. It is worth reading this post in conjunction with my other posts on cavity filters and duplexers; just search the terms. I have written a guide to how duplexers work and have a list of resources on the building and testing of them. https://vk4zxi.blogspot.com/2018/05/the-black-art-of-duplexers-demystifying.html General arrangement The basic design of a single cavity filter is a large diameter aluminium pipe for the cavity and a 1/3 diameter aluminium pipe welded to a top plate. The coupling is mounted on the same plate. The other end of the large pipe is held to another plate by bolts for access. A capacitive hat on a threaded rod is mounted on the bottom plate to tune the cavity. The main pipe is as large as possible to increase the Q of th...