WebSDRs – Remote Web Receivers

Scroll down for some photos of the SDR hardware.

Receiver Links

HF Receiver

The HF receiver is a KiwiSDR coupled with a wide-band WellGood Loop receiving antenna. It covers from DC (well, around 5 kHz) to 32 MHz.

VHF-SHF Receiver

The VHF, UHF and SHF receivers, commonly just the VHF SDR, is a custom made RF front end with helical bandpass filtering for each amateur band listed below. A low-noise front end preamp (based around the MiniCircuits PGA-103+) is employed which does its best to recover weaker signals. Helical filtering tries to keep out-of-band strong signals (of which there are many) from causing issues with the five RTL-SDR V3 dongles used on each band. The antenna is currently a Diamond V2000A at 45m above ground (~135m above sea). The bands and frequencies covered are listed below; bands marked with an asterisk (*) may later be configured to have switchable segments within the band.

  • 6m (50 – 52 MHz)
  • 4m (70 – 72 MHz)
  • 2m (144 – 146 MHz)
  • 70cm (432 – 434 MHz filtered)
  • W70cm (430 – 430 MHz wideband)
  • 23cm (1296 – 1298 MHz)*

Bands are run simultaneously so any changes you make do not affect other users.

Photos of the SDRs

Below is a picture of the HF SDR chassis in the equipment rack.

Below is a picture of the HF SDR enclosure, featuring the KiwiSDR, homebrew PSU PCB, antenna control relays, antenna power bias-tee and other associated parts.

The VHF SDR photo can be seen below. The left PCB is the front-end board with a low noise amplifier, power splitter, and helical filters per band. The SDR receiver modules are under the cooling fan. On top of the cooling fan is a vast amount of dust!

To enable the decoding of digital modes based on the DVSI AMBE Codec, a custom quad AMBE-3000R PCB has been created that enables up to 4 separate concurrent DMR, D-Star, YSF, NXDN, P25 receive streams.