Emphasis for this run was to assess whether the Raspberry Pi 3B+/RSP1a SDR/Cubic SDR/WSJT-X system, which does away with the need for a conventional 12V-powered rig as receiver, works properly.
Three WSPR RX systems running at 14MHz last evening:
(1) Home: FT450, HP laptop, WSJT-X, vertical delta loop
(2) Home: TS480-SAT, Raspberry Pi 4B, WSJT-X, elevated 1/4 wave vertical, 2 elevated radials
(3) Beach (west-facing coast) RSP1A SDR, Raspberry Pi 3B+, WSJT-X (via Cubic SDR), identical 1/4 wave vertical to home.
WSJT-X in all cases was the latest available version.
IO73RF WSPR listening. |
I ran WSPR for 50 minutes (19:14-20:04UT) at the beach, during which time the received signals at any given antenna were broadly stable.
The difference between the vertical at the beach and the vertical at home was a median +8.25dB in favour of the beach, with a range of +3dB to +12dB, based on an analysis of ten randomly-selected stations heard. This result is entirely consistent with previous findings during the late afternoon/evening period from the west coast.
Still a bit of a mess, but at least it all runs off a USB 5V battery, is lightweight, and fits in a backpack! |
The difference between the home delta and home 1/4 wave vertical was a median +5dB in favour of the delta loop, range of -2 to +19.5dB.
So, an elevated vertical at the beach is outperforming an inland full wave vertical delta loop (essentially, a pair of close spaced verticals), by 3dB on average, remembering and accounting for the fact that the 1/4 wave vertical has ~5dB less inherent gain than the delta.
Nearly time to go home. |
Of course, on certain paths, and certain times of day, the beach location makes a very much larger difference. Also, the signal from OX3HI was heard at -28.5dB median signal at the beach, but was not heard at all by either of the home antennas.
1 comment:
Will be looking at getting an RSP1 dx later this year. Mainly for tracing QRN ! Tony G4NGV
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