Andy, > With a slight improvement in the solar flux numbers and the longer periods of > sunlight > in the northern hemisphere, I wonder if we are at the point that 24 hour per > day will be > common using the robust weak signal digital modes?
I think you have it right Andy. Ionospheric models show that the 20 meter band stays open much longer in summer than in winter, especially for locations within the northern hemisphere. A few paths come close to being open for 16 hours or more. The predictions also say that this happens regardless of where we are in the solar cycle and it all seems to correspond well with on-air experience. It seems logical since the summertime ionosphere is exposed to more direct sunlight for much longer periods of time. The polar ionosphere would seem to benefit most from summertime illumination. It seems possible that a slight variation in the 10.7cm solar flux could have some influence on propagation, but I would imagine it's much less significant compared to the seasonal changes. I've learned that it doesn't always go hand-in-hand with conditions and is often misleading... Quoting Robert Brown (NM7M) ... "the 10.7 cm. flux has its purpose, indicating the presence of active regions, and it is a mistake to think that changes in that flux are always associated directly with the state of our ionosphere." > I have been able to work Europe on low power with a vertical as early as 0800 > hrs, in the past > month Europe did not usually open until around 1200 UTC. That's a near perfect match to VOACAP's NY-EU predictions. The predicted 20 meter band openings start around 12:00Z in January and they slowly creep up to 08:00Z in May. > I have been heard in North Carolina at 0730 hrs UTC the past couple of > mornings using > JT65A Could be residual F-region ionization left over from the daylight hours - possibly Sporadic-E. > easy QSO conditions with ZL2BLQ on 20M (CW) around 0200 UTC Nice one Andy - the time coincides with VOACAP. The band is supposed to peak between 0200 and 0400z. Tony -K2MO ----- Original Message ----- From: "Andy obrien" <k3uka...@gmail.com> To: "digitalradio" <digitalradio@yahoogroups.com> Sent: Sunday, May 17, 2009 4:14 AM Subject: [digitalradio] Propagation: 20M all day now with digital modes? > With a slight improvement in the solar flux numbers and the longer > periods of sunlight in the northern hemisphere, I wonder if we are at > the point that 24 hour per day will be common using the robust weak > signal digital modes? With SF=74 and A=0 K=2 the last 2 days, I have > noted that I have been able to work Europe on low power with a > vertical as early as 0800 hrs, in the past month Europe did not > usually open until around 1200 UTC. Also, I have been heard in North > Carolina at 0730 hrs UTC the past couple of mornings using JT65A. I > have had easy QSO conditions with ZL2BLQ on 20M (CW) around 0200 UTC. > > > VE3ODZ-1 (FN03ha) Heard K3UK(FN02) on 14076.14 KHz -15dB at 08:06:00Z > using JT65A > > WD4ELG (FM06kb) Heard K3UK(FN02) on 14076.20 KHz -13dB at 08:06Z using JT65A > Andy K3UK >
