Seeed KiwiSDR metal enclosure finally available!

edited December 2017 in KiwiSDR Discussion
Shipping December 15 it appears:
Preview the assembly instructions here:

1024 x 299 - 118K


  • Looks fine, are they EMC tested?

    Thinking about shielding the VHF (145MHz) spurs




  • jksjks
    edited December 2017
    I did some preliminary tests which showed a big improvement using the enclosure. But I don't have a "typical" 2m rx setup here to observe the real-world effect (i.e. with an actual 2m antenna and feed line). All I can do is relative E-field measurements with the spectrum analyzer. A lot of the problem was observed to be RF conducted on the DC power cable and re-radiated, despite the filtering on the Kiwi board.

    I still need to try things like putting ferrite beads on the SPI clock and data lines. But I believe the problem is more complicated than that. I think it has to do with the fact the ground return path between the Kiwi and Beagle travels over just a few pins of the header connector between the boards. This is an unfortunate limitation of the design where the Kiwi is an add-on board to the Beagle.

    The two boards themselves have good multiple ground planes. Once you get past the Ethernet noise problem (not easy it seems) the Kiwi received spectrum is very quiet. There is little self-interference from the Kiwi or Beagle. There are several examples on of excellent RFI/EMI-free reception. So except for the SPI spur problem the Kiwi works as planned. Remember that you can move the spurs away from 2m by changing the SPI clock frequency setting on the admin page.

  • I should have taken a before and after, but the 8074 KiwiSDR using a 210' top dipole lost most of the noise after installing the enclosure. The 8073 KiwiSDR using the W6LVP loop did not show as much noise reduction, although it did drop most noise by about 6dB, as I observed it. I do not know the exact frequency where the 2 meter spur is located, but I do not find it on an FM radio at 145.000MHz on an outdoor antenna. Perhaps if I set an antenna in the shack I'd find it?

    Anyway very nice enclosure.
    1359 x 922 - 1M
    1359 x 922 - 1M
  • edited December 2017
    OK on 144 MHz. I track it roughly with an FM transceiver and an outdoor antenna, breaking a tight squelch from 144.000-144.010 MHz. It would never matter in my use of 2 meters. If it became a problem a 1/4 wave coax stub on a T connector, trimmed to attenuate the spur might greatly reduce the signal going to the antenna.
  • Collected my enclosure today and will assemble tomorrow. It is now out of stock at Seeed. 

    Bjarne Mjelde
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