[CALV-AUXCOMM] Reminder - NVIS Day Tomorrow April 25

[Shawn Donley]

Calvert AUXCOMM Members,

Just a reminder that Saturday April 25th is NVIS Day beginning at 10:00 AM local and running NLT 4:00 PM.  

The objective is to see how many Calvert AUXCOMM members can communicate with each other on SSB or digital modes using NVIS propagation on 80M and 40M.  All stations that wish to participate should coordinate a 80M or 40M frequency using the CARA 146.985 repeater.  

If you already have a horizontal 80M or 40M antenna, try that.  If you want to try another temporary antenna, go ahead and compare that with your permanent antennas.  The trick to near vertical incidence propagation is to use a horizontally polarized antenna strung a quarter wavelength or less from the ground; less than 60 ft for 80m and less than 30 ft for 40M.  Dipoles are fine. So are end fed wires. Vertical are not suitable.

Besides SSB, you can try digital modes like FT8, PSK31, MT63-1000L and Olivia 8/500.

Please keep a log of stations contacted, their signal report and S-meter reading, the mode used, the antenna type used, and transmit power.

The Ohio ARES group is also having their NVIS day at the same time.  In fact, they started the event a few years ago.   Feel free to tune 80M and 40M to give them a contact as well.  Info on the Ohio activity can be found at http://arrl-ohio.org/SEC/nvis.html

True NVIS propagation involves ionospheric reflection towards the earth below from high angle signals.  Think of it as bouncing a flashlight beam off the ceiling right above your head.   For it to work, the ionosphere has to have sufficient ion density to reflect signals hitting it at such angles.   With the sunspot numbers at this part of the solar cycle, the maximum NVIS frequency will typically be 40M during the daytime and 80M at night.  It's possible that even 7MHz will be above the maximum NVIS frequency during the daylight hours.   It's not unusual for 80M NVIS to drop out in the early evening.   A real-time map of the maximum usable NVIS frequency can be found at http://hamwaves.com/nvis/en/index.html (top right column).

Have fun !

N3AE