Over on YouTubem channel NotaRubicon Productions has uploaded a video describing how a KrakenSDR was used to find the location of a person jamming a repeater site. Amateur radio enthusiasts can utilize VHF or UHF repeater towers, which receive signals from lower power handheld or other radios, and retransmit that signal at high power on a slightly different frequency over a much wider area. Unfortunately malicious people can jam these repeaters by transmitting at the same time as other users, effectively denying use of the repeater by legitimate users.
If you weren't already aware, KrakenSDR is our 5-channel coherent radio based on RTL-SDRs, and it can be used for applications like radio direction finding. We successfully crowd funded the device on Crowd Supply, and the device is currently available for sale on Crowd Supply, Mouser and direct from our website krakenrf.com.
In this video I read the story of how we caught the jammer that had been jamming our GMRS repeater for months, and how by using the KrakenSDR Radio Direction Finder (RF locator), we were at his house in 1 hour.
The KrakenSDR can track a signal being transmitted from 100Mhz to 1Ghz - so I can track ham repeater jammers, GMRS repeater jammers, ham-radio transmitters, GMRS radios - pretty much any transmitter with a signal strong enough for you to receive.
Over on YouTube user Goat Industries has uploaded a video that shows him successfully using his LimeSDR as a 4G repeater. More information about his project to build a cell phone signal repeater can be found on his hackaday.io page, and he describes the project as follows:
In more remote areas it is often not financially viable for the cell network operator to build extra base stations for a small number of people and their phones/modems etc. Fortunately, this is not the end of the road as we can, in theory, build our own base stations and even create our own cells.
There are currently available two groups of devices that already claim to do this, one of which is reassuringly expensive and the other is just plain illegal! This project aims to democratise the situation enabling cost effective, hackable devices to be built that not only work properly but also conform to the telecoms regulations.
In his video he shows the repeater running on his LimeSDR. For software he uses Pothos to create the receiver and LimeSuite to control the LimeSDR settings.
The LimeSDR is advertised as a full duplex RX/TX capable SDR with a 100 kHz – 3.8 GHz frequency range, 12-bit ADC and up to 80 MHz of bandwidth. Back in June 2016 they surpassed their $500k goal, raising over $800k on the crowdfunding site Crowdsupply, and today it’s now up to over $1.1 million. Most crowdfunding backers have now received their units in the mail, but some are still waiting. We paid $199 USD for an early bird unit, and currently a preorder unit costs $289 USD on Crowd Supply.
SvxLink is an EchoLink and general purpose voice services system for controlling ham radio repeaters. A repeater is a radio tower that receives a weak transmission from a handheld or remote radio and then repeats the same message with greater power over a wide area. With repeaters radio communications can cover a much further distance.
Ham radio enthusiasts often set up repeaters for their own frequencies, so that they can be heard over a wider range. To control the repeater software like SvxLink is required. In the latest software update of SvxLink they added RTL-SDR support. They write:
The biggest news in this release is the support for RTL2832U based DVB-T USB dongles. This make it possible to use such USB dongles as cheap SDR (Software Defined Radio) receivers. This will open up the world of cheap receiver hardware to all SvxLink users. It will for example be very cheap to set up an extra receiver with local coverage for a SvxLink based repeater, as long as there is a network connection to the repeater. The modulation forms supported are: FM, FM narrow, AM, AM narrow, USB, LSB, CW, CW wide and wideband FM (broadcast). Running multiple receivers on the same dongle is supported as well as using multiple dongles.