DF6NM 10uW ERP at 8270 Hz at Todmorden, 1028 km.
S/N and phase (lead) in 278 uHz (1 hour) averages
Start ---H-field---- ---E-field----
00:30 6.8 dB -51.2 -0.7 dB
01:00 4.7 dB -50.5 -7.3 dB
01:30 8.5 dB -49.0 12.9 dB -61.0
02:00 10.6 dB -65.4 13.5 dB -63.3
02:30 11.5 dB -82.1 11.5 dB -67.8
03:00 11.5 dB -94.9 10.4 dB -84.6
03:30 10.6 dB -112.9 11.9 dB -77.9
04:00 11.1 dB -119.6 14.0 dB -79.1
04:30 12.3 dB -108.7 13.6 dB -98.3
05:00 12.3 dB -103.8 10.1 dB -94.5
05:30 13.8 dB -108.1 12.9 dB -101.8
06:00 12.5 dB -97.8 14.9 dB -103.1
06:30 10.4 dB -80.6 11.8 dB -91.5
07:00 10.6 dB -92.0 11.1 dB -83.2
07:30 11.0 dB -96.6 10.8 dB -87.8
08:00 10.9 dB -84.8 8.5 dB -78.2
08:30 12.6 dB -73.6 9.1 dB -79.2
09:00 14.1 dB -74.7 10.8 dB -89.8
Phase is steady enough from 02:00 to 10:00.
02:00 to 10:00 averages:
Flux density 0.09 fT
In 34.7 uHz: H field 20.4 dB, E field 20.8 dB
In 278 uHz: H field 10.9 dB, E field 11.0 dB
In 278 uHz: E+H combined: 14.3 dB
Considering just the H-field and allowing 0.5 dB margin, that's
just enough for 17 characters, 12.5 second symbols, rate 1/16 K=25.
Eb/N0 would be about -0.6 dB, and 81% of capacity.
I tend not to factor in the E-field rx for these estimates, it
is more susceptible to weather and some nights can be useless
for weak signals. It is useful to keep in reserve.
But last night the E-field was very good. Using it, we
could try a less strong code, rate 1/8 K=21. This has about
0.5 dB or so less coding gain but is capable of being decoded on
a domestic PC. Rate 1/8 K=21 symbol period 16 seconds, 31
character message, Eb/N0 around -0.2 dB, for 77% of capacity.
--
Paul Nicholson
http://abelian.org
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