Hello to all stations that checked into the WMA ARES HF Emergency Net on Sunday October 11.
You’ve probably noticed that I’ve requested your power levels to be reported also … this is to assist in studying some of the 75m ionospherics at play during our net relative to the time and your location. I’ve attached a table of your received signal strengths at my station here in Southwick MA for your information. Receive antenna is a multi band Off Center Fed Dipole (OCFD) at about 70 feet into a Yaesu FT-1000MP. Results are interesting especially at low and QRP power levels.
While I have not calibrated the meter at this point, I believe the readings vs power levels vs distance from the station will give us a better idea of what could be the case in a large scale emergency where 100 watts might be the maximum power a station could produce – especially if deployed. Near Vertical Incident Skywave (NVIS) signals are the defacto mode of communication for our nets due to the typical heights of our antennas. This is usually a good medium for reliable communications out to 300 miles or so. However, there has been information published that describes a ‘donut hole’ of about 100 miles that may pop up depending on the condition of the ionosphere with time…most likely the D and E Layer absorption growing as the sun heats things up.
Certainly other layers and factors affect our efforts and I’m trying to get a handle on all this by collecting reports and trying to relate things to ionosphere level readings taken at the same time as our net from the nearby ionosonde site at Millstone Hill in MA. I will keep you advised of any findings as I study the voluminous data on ionograms and their translations on the web. I am pretty new to this and the data available is primarily at research science levels so if any of you are well – versed or have a potential contact that might be, I’d appreciate your inputs <grin>!
I’m going to try to collect and refine readings going forward and will make these available as I collect them … at a location to be determined – possibly posted here for the time being.
Thanks to all of you for your net participation and your willingness to serve your communities in disaster situations.