Additions:
Use the lowest planned frequency when choosing radial schedules. Radials should be equal length, straight and distributed evenly. They can be on the surface or buried to a shallow depth. Effectiveness will be reduced with deep burial. Distributing the radials unevenly still works, but there is some reduction in performance. Clearly bunding them into one rope would not be as effective as distributing them..
Deletions:
Use the lowest planned frequency when choosing radial schedules. Radials should be equal length, straight and distributed evenly. They can be on he surface or buried to a shallow depth. Effectiveness will be reduced with deep burial.
Additions:
For a given length of radial wire (close to earth), frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU (reference below) article calculates a formula for this: (see formula below). The K3LC article (link below) derives curves from exhaustive modelling runs. The results are very similar.
Deletions:
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU (reference below) article calculates a formula for this: (see formula below). The K3LC article (link below) derives curves from exhaustive modelling runs. The results are very similar.
Additions:
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU (reference below) article calculates a formula for this: (see formula below). The K3LC article (link below) derives curves from exhaustive modelling runs. The results are very similar.
N4UU Optimal Radial Equation:
n = 2.25 * sqrt( sqrt( s * f )) * sqrt(L)
s is soil conductivity in S/m (average is 0.0045 S/m)
f is design frequency in MHz
L is total radial wire length in feet
n is number of radials to cut into
40 meters: approx 25 each 20 foot radials
80 meters: approx 16 each 31 foot radials
160 meters: approx 12 each 41 foot radials
40 meters: approx 14 each 18 foot radials (252 feet)
80 meters: approx 10 each 25 foot radials
Use the lowest planned frequency when choosing radial schedules. Radials should be equal length, straight and distributed evenly. They can be on he surface or buried to a shallow depth. Effectiveness will be reduced with deep burial.
Refer to the K3LC paper or the N4UU articles linked below for further details.
Deletions:
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU (reference below) article calculates a formula for this: (insert formula). The K3LC article (link below) derives curves from exhaustive modelling runs. The results are very similar.
40 meters: approx 25 each 20 foot radials
80 meters: approx 16 each 31 foot radials
160 meters: approx 12 each 41 foot radials
40 meters: approx 14 each 18 foot radials (252 feet)
80 meters: approx 10 each 25 foot radials
Use the lowest planned frequency when choosing radial schedules.
Refer to the K3LC paper below for further details.
Additions:
In these optimizations the vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in and how to cut it. The radials are close to earth, and varying earth parameters change the optimal radial results slightly. Design the radial system for the lowest frequency to be used. This will generally give the overall best performance for this quantity of radial wire on all bands (better than cutting some radials for each band).
Deletions:
In these optimizations the vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in and how to cut it. The radials are close to earth, and varying earth parameters change the optimal radial results slightly. Note that elevated radials generally need to be resonant for best performance.
Additions:
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU (reference below) article calculates a formula for this: (insert formula). The K3LC article (link below) derives curves from exhaustive modelling runs. The results are very similar.
In these optimizations the vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in and how to cut it. The radials are close to earth, and varying earth parameters change the optimal radial results slightly. Note that elevated radials generally need to be resonant for best performance.
Deletions:
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU (reference below) article calculates a formula for this: (insert formula). The K3LC article (link below) derives curves from exhaustive modelling runs. The results are similar.
In these optimizations the vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in and how to cut it.
Additions:
In these optimizations the vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in and how to cut it.
Deletions:
In these optimizations the vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in.
Additions:
Note that verticals (or base fed Inverted L's) become less dependent on the ground radial system as they tend toward 1/2 wavelength. At 1/2 wavelength the impedance is very high and the ground radial currents are very low, so losses in the radials are not significant. Indeed, users of 1/2 wave antennas often claim no ground radials are required, and use none, but they are instead using the feedline shield and transmitter cabinet as their counterpoise.
To give one specific example (based on the data in the K3LC paper), assume one has a modest 500 foot spool of wire for radials over average soil (0.005,13). The optimal configuration of the 500 feet of wire depends on the band:
Deletions:
Note that verticals (or base fed Inverted L's) become less dependent on the ground radial system as they tend toward 1/2 wavelength. At 1/2 wavelength the impedance is very high and the ground radial currents are very low, so losses in the radials are not significant. Indeed, users of 1/2 wave antennas often claim no ground radials are required, and use none, but they are instead using the feedline shield and cabinet as their counterpoise.
To give one specific example (based on the data in the K3LC paper), assume one has a modest 500 foot spool of wire for radials. Assume further average soil (0.005,13). The optimal configuration of the 500 feet of wire depends on the band:
Additions:
Note that verticals (or base fed Inverted L's) become less dependent on the ground radial system as they tend toward 1/2 wavelength. At 1/2 wavelength the impedance is very high and the ground radial currents are very low, so losses in the radials are not significant. Indeed, users of 1/2 wave antennas often claim no ground radials are required, and use none, but they are instead using the feedline shield and cabinet as their counterpoise.
Deletions:
Note that verticals (or base fed Inverted L's) become less dependent on the ground radial system as they tend toward 1/2 wavelength. At 1/2 wavelength the impedance is very high and the ground radial currents are very low, so losses in the radials are not signficant. Indeed, users of 1/2 wave antennas often claim no ground radials are required, and use none, but they are instead using the feedline shield and cabinet as their counterpoise.
Additions:
For another example, assuming a 250 spool of wire is available and we want to make some radials for a portable use of a screwdriver antenna over average ground. According to the chart in the K3LC paper:
Deletions:
For another example, assuming a 250 spool of wire is available and we want to make some radials for a screwdriver antenna over the same average ground. According to the chart in the K3LC paper:
Additions:
Shorter verticals are even more dependent on radials than quarterwave verticals.
For another example, assuming a 250 spool of wire is available and we want to make some radials for a screwdriver antenna over the same average ground. According to the chart in the K3LC paper:
40 meters: approx 14 each 18 foot radials (252 feet)
80 meters: approx 10 each 25 foot radials
Use the lowest planned frequency when choosing radial schedules.
Deletions:
Shorter verticals are even more dependent on radials than quarterwave vertcials.
Additions:
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU (reference below) article calculates a formula for this: (insert formula). The K3LC article (link below) derives curves from exhaustive modelling runs. The results are similar.
In these optimizations the vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in.
Shorter verticals are even more dependent on radials than quarterwave vertcials.
To give one specific example (based on the data in the K3LC paper), assume one has a modest 500 foot spool of wire for radials. Assume further average soil (0.005,13). The optimal configuration of the 500 feet of wire depends on the band:
Refer to the K3LC paper below for further details.
--
AlanB, WB6ZQZ
Deletions:
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU article calculates a formula for this: (insert formula). The K3LC article derives curves from exhaustive modelling runs. The results are similar.
The vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in.
To give one specific example, assume one has a modest 500 foot spool of wire for radials. Assume further average soil (0.005,13):
--
AlanB
Additions:
The vertical is assumed to be a quarterwave. The overall system gain is derived as a function of the total length of radial wire. This tradeoff can help one decide how much radial wire to invest in.
Note that verticals (or base fed Inverted L's) become less dependent on the ground radial system as they tend toward 1/2 wavelength. At 1/2 wavelength the impedance is very high and the ground radial currents are very low, so losses in the radials are not signficant. Indeed, users of 1/2 wave antennas often claim no ground radials are required, and use none, but they are instead using the feedline shield and cabinet as their counterpoise.
To give one specific example, assume one has a modest 500 foot spool of wire for radials. Assume further average soil (0.005,13):
Deletions:
To give one example, assume one has a 500 foot spool of wire for radials. Assume further average soil (0.005,13):
Optimal Radials for Vertical Antennas
For a given length of radial wire, frequency and ground conditions there is an optimal way to cut the wire into radials to optimize overall gain. The N4UU article calculates a formula for this: (insert formula). The K3LC article derives curves from exhaustive modelling runs. The results are similar.
To give one example, assume one has a 500 foot spool of wire for radials. Assume further average soil (0.005,13):
40 meters: approx 25 each 20 foot radials
80 meters: approx 16 each 31 foot radials
160 meters: approx 12 each 41 foot radials
References
--
AlanB
CategoryHamRadio