Andy, NVIS simplified means a very high angle antenna and operating below the critical frequency.
At mid latitudes it may mean 80 meters and lower frequencies. At my latitude (23 N) sometimes 40 meters qualifies. Of course, tricks may be done to enhance skywards radiation, like using wires below your antenna to mimic a 2 element yagi of sorts, I have read that three wires as counterpoise makes a good compromise. What you need is a cloud warmer, and operating below the critical frequency, where the ionosphere becomes "transparent" to your RF....and you might get a looong DX reply from selenites or martians. Look on the Internet for f0f2 for your area, and choose a frequency somewhat below it. It is not advisable to go too low, as noise and D layer absorption will play against you. Jose, CO2JA --- Andrew O'Brien wrote: > My entry in to amateur radio was via 10 meters and the quest for DX, > I had no real interest in "local" communication. Over the years I > have had hams ask me to help them set-up their stations for digital > mode operation and have occasionally resorted to the lower bands in > attempt to help them. Often my attempts to communicate with hams in a > 10-50 mile radius has failed. During darkness, I "skip" over them, > and during the day-light we can't hear each other. > > I know 10 and 20 meter daylight propagation characteristics like the > back of my hand, but have no clue about what is "normal" for 80 and > 40M . It seems odd to me that I would have to rely on 2M repeaters to > talk to regional hams. What do others on this list do for regional > communications on HF? It would seem to me that the digital modes > would be ideal for regional use but whenever I get a chance to get > someone brave enough to leave 2M chatting alone and try a digital > mode on HF, I can't work 'em to help them get set-up. > > I am familiar with NVIS antennae but do not have a particular NVIS > installation, I do not have real estate for 160M either. So what > bands and "regular" antennas do you use for this ? > > -- Andy K3UK Skype Me : callto://andyobrien73 <callto://andyobrien73> > www.obriensweb.com >
