Trials and Errors Issue #48: Guest Article - WSPR, The Mode that Ensures You are Getting Out!

Real scientific testing of antennas using WSPR

https://forums.qrz.com/index.php?threads/comparing-two-antennas-using-wspr.947135/

 

Thanks Steve -- good addition to the thread, Dave

 

MH370 and WSPR: .....rather far-fetched and silly....
Maybe farfetched, why silly? If you did not study a subject in detail and you do not understand the physics on that subject, why do you declare it silly? Is this ham radio at the frontier of technology or just one-track-mind attitude?

We have the U-turn of MH370 at 17:22 h UTC at a Drift rate of -1 from HS to VK1 and VK3 recorded for years now. Inmarsats pings (below 10) and more than a 100 WSPR signals are the only electromagnetic signals available after all ATC, military radars etc. failed.

We studied HF WSPR signals (primary and secondary) worldwide with emphasis on missions of exploration ship Polarstern to Arctica as well as Antarctica with recorded WSPR signals compared to Flightradar24 and EDS-B data from jets, propeller aircraft, helicopters, military targets, airborne and spaceborne within the ionosphere.

We choose these regions in order to reduce any ambiguities. Inmarsat satellite signals as well as WSPR signals have not been designed for this purpose anyway we are short on anything more appropriate.

Even with WSPR HABs (High Altitude Ballon) such as LU1ESY at 10 mW across the SIO (Southern Indian Ocean) "illuminating" aircraft in a Forward Scattering mode.

From month to month we make good progress to better understand the whole "silly" process and do our best to keep amateur radio at the forefront of technology at the risk that the majority of well established radio amateurs (for decades now) will not be able or willing to follow us as well as risking rejection (for how long?) of K1JT, whom we respect and greatly admire for creating WSPR as our current tool box for doing this kind of work.

73 and all the best to you de DJ4FF

 

The cost is nearly zero. You can transmit WSPR using any SSB transmitter plus a mobile phone to generate the FSK sounds. You don't even need a radio, as you can transmit 3 to 10 dBm WSPR signals from the GPIO pin of a Raspberry Pi run through a low pass filter to your antenna. With a good antenna, 10 dBm of WSPR can occasionally get one some DX spots. No need for 100W, or even 5W or 1W.

 

Best of luck. I hope you prove me wrong, as I have been wrong in the past. But I will be very curious to see how it could be done, and I will view the process highly critically.

 

2026.02.09: HAB ZS1ERZ, altitude app. 13.000 m, has been in the vicinity of the assumed LEP of flight MH370 in grid locator NG91. The floater's WSPR signals (0,02 Watt or 20 mW) have been received in distances 3.000 km to 6.000 km at 28 MHz in most cases. Maximum distance 16.935 km at KFS.

The transmissions started at 01:22 h UTC as PV power for electronics (GPS, WSPR TX) has been still down at dawn (no battery). Numerous WSPR signals drift rates up to -4 (9V1KG-2 at 03:02 h UTC) registered. These correspond to aircrafts passing by, identified by use of ADS-B data from Flightaware, FR24...others drift rates 0, 1, -1, -2, -4,...

The HABs' data can be found at amateur.sondehub.org...

After 4 h UTC distances extended to more than 10.000 km. 01:32 h UTC to 02.02 h UTC more than 16.000 km to USA KD7EFG, KFS, KFS/OMNI from HAB, call sign ZS1ERZ, in grid NG82 (Drift rates -1). Next grids NG92, OG02, OG01. Last WSPR signals of the day received at 9V1, BU, at 09:52 h UTC (Dusk started East of Taiwan). Further examples: Australia VK1DF with drift rates -2, -1, 0, +1; VK5ARG, Philippines DU2FIS (Drift rates -4, -3, -2, 0), Taiwan (BU2DR, BM7GUP)

Please do your own observations as long flight data will be available at no cost in FR24 (5-7 days) and WSPR data base (2 weeks at least).
More detailed analysis for interaction with aircraft is needed. Similar observations 2026.02.10 ZS1AFB in the Pacific and flights to Mataveri, ZS6SRC in SIO....

First conclusion: Very low power WSPR signals above flight level from that area (LEP of MH370) in the SIO (Southern Indian Ocean) can be received over very long distances! Various drift rates have been noticed.

Interactions with other aircraft need to be investigated further, for example WSPR signals from grid NG92 to 9V1, DU, VK5, .... ; some fit nicely to aircraft in vicinity with drifts from zero up to -4 (9V1KG-2 at 03:02 h UTC)!

HAB: High Altitude Balloon; LEP: Last Estimated Position; MH370: Flight of jet B777 from KUL on 2024.03.07/08, SIO: Southern Indian Ocean