27 December, 2017

QRSS experiments: FSKCW and Slow Hell

These last few days I've been experimenting with my QRPLabs Ultimate 2 and Ultimate 3s transmitting on 7 MHz. In addition to WSPR, the modes transmitted have been FSKCW with 6 second long dots, and Slow Hell with 17 second long characters. The result as received this morning can be seen on the display from the grabber of Les, G3VYZ in Northumberland, UK. This is a stack of 6 consecutive 10 second frames as can be found on the QRSS grabber site of AJ4VD.

FSKCW and Slow Hell reception of LA3ZA at G3VYZ

My signal is on 7,039.870 kHz and has been set up with a FSK shift of 6 Hz. Power output was 0.2 W and the distance is about 890 km.

It works but the reception is much less reliable than for WSPR, which is not so unexpected. At the same time the WSPR signal was received all around Northern Europe (G, GM, DL, ON, OE, LX, LA, OY, OH, PA, SM) as well as on the Canary Islands, 3930 km away.

24 December, 2017

FT8 anomaly or long delayed echo?

My friend Alf, LA2NTA, has sent me these screenshots from when he has been operating FT8. The first image is when operating 10 meters and took place early in November.

Two of LA2NTA CQs being received by himself on 10 meter (in red)

It shows how his own CQ comes back to him at 10.54.00 and at 11.00.00 and is decoded in his own receiver. The echoes return at the time of transmission.

The second example is from 20 meters and took place just a few days ago.

LA2NTA CQ being received by himself on 20 meter (in red)

For the first example he also took an image of the spectral display. It shows lots of repeated noise burst all over the FT8 band.

FT8 band on 10 meters showing some form of noise all over the band

It is hard to explain this, but my hunch is that it is something local and not a propagation phenomenon, but who knows?