HFU HF Underground
Technical Topics => Equipment => Topic started by: jordan on June 03, 2014, 1930 UTC
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Let's say a person lives in a western Detroit suburb (Livonia, Westland, Garden City, etc). Would it be possible to talk to someone in Lansing using ham radio? If so, what frequencies would work for that? It seems like it's too far for 2M/440 to be effective, and too close for any HF communications to work; it would be within the skip zone.
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The skip zone on HF is frequency and time of day dependent (well, and solar activity dependent also). The distance appears to be about 100 miles? NVIS is perfect for that. It's actually what pirates are using on 43 meters during the daytime, good for a few hundred miles out. I'd suggest 40 meters (or maybe even 80 meters) during the daytime, and 80 meters at night. YMMV depending on solar conditions.
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The skip zone on HF is frequency and time of day dependent (well, and solar activity dependent also). The distance appears to be about 100 miles? NVIS is perfect for that. It's actually what pirates are using on 43 meters during the daytime, good for a few hundred miles out. I'd suggest 40 meters (or maybe even 80 meters) during the daytime, and 80 meters at night. YMMV depending on solar conditions.
By 43 meters, do you mean frequencies such as 6930 kHz? How exactly does NVIS work? What kind of antenna do you need, and how would you configure it?
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NVIS Near Vertical Incident Sky Wave: http://www.radiohobbyist.org/blog/?p=245
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Most UK ham to ham operation (beyond simple 2m FM) is on 40m (80m at night). 2m SSB, 4m and 6m all have a strong niche following. However, 6m is highly dependent on sporadic E propagation. 160m is quite good for local comms (better at night) lots of space needed though, as you're essentially a MW station!
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For 80 and 40 meter NVIS work, put a dipole up at about 10 to 20 feet. The low height causes most of the signal to go straight up, and then it is reflected straight down. Really works well in the mountains here where most other stuff is blocked by the mountains. 6 meters would also work for that distance if you have a beam and run SSB. A lot of the fire departments in this area use lowband VHF because of the terrain, it can get out when the other stuff can't. You could also try 2 meter SSB over that distance if you had a beam and there isn't anything to block the path. I've worked 2 meter FM simplex at 80 miles with just 5 watts and a vertical, but the other station was up on a mountain, which did help. With a pair of good beams and about 50 watts, there's no reason two stations couldn't work each other on 2 meters, SSB would be easier because of the weak signals.
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Relatively flat ground it looks like and maybe 70 miles? I would be willing to bet 160 meters would provide 24 hour coverage primarily in ground wave. 80 would also probably work 24 hours a day, and 40 almost all the time. I use 160 and 80 meters when 4x4ing in the desert, and generally can phone home under most conditions when I am inside 100 miles of home.
At 70 miles and if few mountains 2M SSB with moderate gain antennas (say 13 elements) might be viable.
Of course, if repeaters are your bag I bet there are a few around that can be hit from both locations.
T!
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FWIW, I've heard locals chatting on 17 meters (the 18 mhz ham band), they were about 40 miles from me and maybe 40-60 miles from each other. So even higher bands are possible, obviously depending on the radio and antenna.
Like the others said, 40 meters and the lower bands will also work. I live in Washington state and hear hams in Washington and BC Canada talking to each other during the day (usually I hear them mid to late mornings), sometimes with guys from Oregon and Idaho also. Some of them may be more than 100 miles from each other.
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75M will work well too. We have numerous gatherings on 75M during early AM, thru evening.
At times, there is absorption, QSB, or in worst case solar disturbances... dead band.
Antenna is obviously larger (longer) than resonant 40M wire, but at typical ham heights of <40' in the air, it's actually a NVIS antenna. Can be end fed, 122' of wire with an AT at the feedpoint. My inverted L of 122', 40' vertical and 80' horizontal fed with an Icom AH-4 Auto Tuner plays VERY well on all bands. One 120' counter poise is laying on the ground beneath it and other random lengths are laying away from the feed point.
73 de Kriss KA1GJU