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When it comes to something like 4 1/4 wavelength or 8 1/8 wavelength radials performing about the same, and sometimes even better. This is referring to a radial system that is on or just above the earth. In this case this isn't a big deal because the antenna currents on the radials do not electrically end at the ends of the radials, and in fact continues on the earth past the radials.

However, the antenna in question is an elevated antenna that is typically mounted orders of magnitude higher than a "few feet" above the earth. There is no nearby earth in such systems for the currents on said radials to continue past said radials. Because of this, this becomes a different animal entirely. In this case, the radial lengths are electrically more a part of the antenna system, and a change in this setup will have much more of an effect on the antenna's feed point impedance.

I don't think that shortening the vertical element of the antenna alone will be enough to account for this change, very likely an adjustment to the antenna's matching system will be in order as well. I don't know if it will have enough tuning range to account for this change or not.

As mentioned above, this setup will also not be as effective at combating common mode currents, which along with making tuning an antenna easier is the main benefit of having a full length radial system on an elevated antenna so if this becomes an issue you may need to invest in an RF choke.

The dB

<blockquote data-quote="The DB" data-source="post: 727168" data-attributes="member: 21346">When it comes to something like 4 1/4 wavelength or 8 1/8 wavelength radials performing about the same, and sometimes even better.&nbsp; This is referring to a radial system that is on or just above the earth.&nbsp; In this case this isn&#039;t a big deal because the antenna currents on the radials do not electrically end at the ends of the radials, and in fact continues on the earth past the radials.However, the antenna in question is an elevated antenna that is typically mounted orders of magnitude higher than a &quot;few feet&quot; above the earth.&nbsp; There is no nearby earth in such systems for the currents on said radials to continue past said radials.&nbsp; Because of this, this becomes a different animal entirely.&nbsp; In this case, the radial lengths are electrically more a part of the antenna system, and a change in this setup will have much more of an effect on the antenna&#039;s feed point impedance.I don&#039;t think that shortening the vertical element of the antenna alone will be enough to account for this change, very likely an adjustment to the antenna&#039;s matching system will be in order as well.&nbsp; I don&#039;t know if it will have enough tuning range to account for this change or not.As mentioned above, this setup will also not be as effective at combating common mode currents, which along with making tuning an antenna easier is the main benefit of having a full length radial system on an elevated antenna so if this becomes an issue you may need to invest in an RF choke.The dB</blockquote>

[QUOTE="The DB, post: 727168, member: 21346"] When it comes to something like 4 1/4 wavelength or 8 1/8 wavelength radials performing about the same, and sometimes even better. This is referring to a radial system that is on or just above the earth. In this case this isn't a big deal because the antenna currents on the radials do not electrically end at the ends of the radials, and in fact continues on the earth past the radials. However, the antenna in question is an elevated antenna that is typically mounted orders of magnitude higher than a "few feet" above the earth. There is no nearby earth in such systems for the currents on said radials to continue past said radials. Because of this, this becomes a different animal entirely. In this case, the radial lengths are electrically more a part of the antenna system, and a change in this setup will have much more of an effect on the antenna's feed point impedance. I don't think that shortening the vertical element of the antenna alone will be enough to account for this change, very likely an adjustment to the antenna's matching system will be in order as well. I don't know if it will have enough tuning range to account for this change or not. As mentioned above, this setup will also not be as effective at combating common mode currents, which along with making tuning an antenna easier is the main benefit of having a full length radial system on an elevated antenna so if this becomes an issue you may need to invest in an RF choke. The dB [/QUOTE]

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