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There are 4 relevant MF and HF propagation types available:
Skywave skip (uses either horizontal or vertical polarized antennas; can be used on all HF bands);
NVIS skywave (uses horizontal polarization and lower HF frequencies, usually 1.8-20, 3,5-4, and 7-7.3; sometimes [depending on solar flux] 10.1 and 14 to 14.35 MHz);
HF line of sight (uses either horizontal or vertical polarization, can be used on all HF bands, does not depend on either ground wave propagation or reflection from the ionosphere.)
HF ground wave. Ground wave propagation must be vertically polarized, and can be adversely affected by terrain or geologic discontinuities between the transmitting station and the receiving station. The lower the frequency, the better the ground wave propagation.
Ground wave does not work well when there is sharp terrain, such as ridges or deep valleys between stations, and distance significantly attenuates the signal, requiring more power to get reliable communications, 80 and 160 meters (1.8 and 3.5 MHz), where ground wave out to 50 miles or so *is* practical, at least on relatively flat ground, requires large vertical antennas with extensive radial systems to be effective. These are NOT easily portable, and they are tall antennas; a 1/4 wave vertical on 80 meters is about 65 to 70 feet tall and requires at least 4 radials to be minimally effective; most knowledgeable people recommend at least 60 radials on the ground at least 35 feet long for a decent antenna.
The other point to be made about ground wave is that when you try to use it, especially on the upper HF bands, you are simultaneously generating a HF signal that will propagate via skip to a very long distance, and expose your HF communication to being DFd. People all over the world will hear your signals.
For field expedient local communication that is not impacted by terrain, uses low power, is easy to set up, hard to DF, and does not require tall trees, I would use NVIS. Near Vertical Incidence Skywave bounces lower HF signals off the F layer(s) of the ionosphere. It uses simple horizontal antennas at low elevation above ground; it is possible to simply lay the antenna on the ground and get effective transmission and reception. This technique provides reliable HF communication out to 3-500 miles with no skip zone, and works reliably regardless of the intervening terrain. I have made a number of contacts on 160, 80 and 40 meters using NVIS with low horizontal dipoles and under a watt of power; I get excellent signal reports regardless of the time of day or the solar flux.
I have also made contacts using ground wave on 80 meters and those contacts were intermittent past a few miles, likely due to the rough terrain in my immediate neighborhood, and the difficulty in getting a good vertical up on 80.
I agree that HF is hugely useful for local, regional, and long distance communication, but ground wave is an inferior choice of propagation type.
73 and regards to all who serve the Light,
Historian
Yeah, he lost my confidence when he mentions using FRS for 3.3 miles. On what planet is this guy operating a radio? Here on earth, FRS goes a few blocks, maximum. I know, I know, unless one of you is in the middle of a lake, and one of you is on top of a mountain and you jack the power way up somehow, etc etc.
Actually, FRS and the other VHF allocations in the 150 MHz range can be effective at much greater distances, if proper antennas are used. The antenna is key here. A good J-Pole whip made from window line or 300 ohm twin lead is a considerable improvement over the small rubber ducks the FRS units are usually equipped with.
One of the advantages of some of the commercial MURS units is that they come with a user-removeable antenna which allows easy connection of external antennas. I have communicated at distances over 150 miles LOS using an old Icom 2AT 2 meter HT with a 5/8 wave vertical and two watts.
Using small handheld 3 or 4 element Yagi antennas can extend that distance considerably; the key is having unobstructed line of sight.
Trees and vegetation make good RF sponges, especially at VHF and up.
If you are operating in rugged heavily vegetated areas, consider HF NVIS instead for group to group comms.
nice, theres a lot of good info in this video
Nice video.. one correction – FCC does not permit repeaters on the MURS band.
You’re right. It’s GMRS which allows repeaters. Dang it when I do that.
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There are 4 relevant MF and HF propagation types available:
Skywave skip (uses either horizontal or vertical polarized antennas; can be used on all HF bands);
NVIS skywave (uses horizontal polarization and lower HF frequencies, usually 1.8-20, 3,5-4, and 7-7.3; sometimes [depending on solar flux] 10.1 and 14 to 14.35 MHz);
HF line of sight (uses either horizontal or vertical polarization, can be used on all HF bands, does not depend on either ground wave propagation or reflection from the ionosphere.)
HF ground wave. Ground wave propagation must be vertically polarized, and can be adversely affected by terrain or geologic discontinuities between the transmitting station and the receiving station. The lower the frequency, the better the ground wave propagation.
Ground wave does not work well when there is sharp terrain, such as ridges or deep valleys between stations, and distance significantly attenuates the signal, requiring more power to get reliable communications, 80 and 160 meters (1.8 and 3.5 MHz), where ground wave out to 50 miles or so *is* practical, at least on relatively flat ground, requires large vertical antennas with extensive radial systems to be effective. These are NOT easily portable, and they are tall antennas; a 1/4 wave vertical on 80 meters is about 65 to 70 feet tall and requires at least 4 radials to be minimally effective; most knowledgeable people recommend at least 60 radials on the ground at least 35 feet long for a decent antenna.
The other point to be made about ground wave is that when you try to use it, especially on the upper HF bands, you are simultaneously generating a HF signal that will propagate via skip to a very long distance, and expose your HF communication to being DFd. People all over the world will hear your signals.
For field expedient local communication that is not impacted by terrain, uses low power, is easy to set up, hard to DF, and does not require tall trees, I would use NVIS. Near Vertical Incidence Skywave bounces lower HF signals off the F layer(s) of the ionosphere. It uses simple horizontal antennas at low elevation above ground; it is possible to simply lay the antenna on the ground and get effective transmission and reception. This technique provides reliable HF communication out to 3-500 miles with no skip zone, and works reliably regardless of the intervening terrain. I have made a number of contacts on 160, 80 and 40 meters using NVIS with low horizontal dipoles and under a watt of power; I get excellent signal reports regardless of the time of day or the solar flux.
I have also made contacts using ground wave on 80 meters and those contacts were intermittent past a few miles, likely due to the rough terrain in my immediate neighborhood, and the difficulty in getting a good vertical up on 80.
I agree that HF is hugely useful for local, regional, and long distance communication, but ground wave is an inferior choice of propagation type.
73 and regards to all who serve the Light,
Historian
Yeah, he lost my confidence when he mentions using FRS for 3.3 miles. On what planet is this guy operating a radio? Here on earth, FRS goes a few blocks, maximum. I know, I know, unless one of you is in the middle of a lake, and one of you is on top of a mountain and you jack the power way up somehow, etc etc.
…and there you go. Bingo.
Actually, FRS and the other VHF allocations in the 150 MHz range can be effective at much greater distances, if proper antennas are used. The antenna is key here. A good J-Pole whip made from window line or 300 ohm twin lead is a considerable improvement over the small rubber ducks the FRS units are usually equipped with.
One of the advantages of some of the commercial MURS units is that they come with a user-removeable antenna which allows easy connection of external antennas. I have communicated at distances over 150 miles LOS using an old Icom 2AT 2 meter HT with a 5/8 wave vertical and two watts.
Using small handheld 3 or 4 element Yagi antennas can extend that distance considerably; the key is having unobstructed line of sight.
Trees and vegetation make good RF sponges, especially at VHF and up.
If you are operating in rugged heavily vegetated areas, consider HF NVIS instead for group to group comms.
NVIS… It works every day and it works for regional comms, without much power and without much skip.