KiwiSDR 2 Pre-Announcement

KiwiSDR is a 14-bit wideband RX only HF software defined radio created by John Seamons (ZL/KF6VO). The KiwiSDR has up to 32 MHz of bandwidth, so it can receive the entire 10 kHz - 30 MHz VLF/LF/MW/HF spectrum all at once. Other than the specifications, the main interesting feature about the KiwiSDR is that it is designed to be operated entirely as an online web based SDR which is accessed over a network connection. Owners can optionally share their KiwiSDRs online with anyone who wants to access it, which also allows for interesting distributed applications, such as TDoA direction finding, which allows users to pinpoint the location of unknown HF transmissions such as numbers stations.

KiwiSDR 2 has recently been "pre-announced" by creator John Seamons on the KiwiSDR forums. The changes to the design are not huge, but they bring a few iterative improvements. He writes:

KiwiSDR 2 Goals:

Minimal changes. Fastest time-to-market with lowest possible risk. BUT since the PCB is going to be re-spun fix some of the known limitations that don't add too much risk:

  • New RF front-end:
  • Balanced input via balun transformer
  • Digital attenuator (per the advisory group: pSemi PE4312, 0 - 31.5 dB, 0.5 dB steps)
  • Gas discharge tube (GDT) across input in addition to TVS diodes
  • Static drain resistors (100K) from input connections to ground
  • External ADC clock brought out on third SMA connector
  • Self test loopback mode using a short cable between this SMA and antenna input
  • New GPS chip to replace current one which is now EOL
  • Reverse polarity protection (via P-FET) on 5V DC input
  • TVS diode across 5V input
KiwiSDR 2 PCB Design
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