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I try to think. Sometimes it works. Yes, cross polarization introduces about 20dB system loss. That was not the issue. The guy asked about verticals for local work.

If he has problems with local QRM the answer is more in what he can notch out rather than maximum forward gain. A Maco 5 element yagi has very deep nulls at 90 degrees each side of the forward lobe. Point that at the offender and the signal will pretty much vanish. It also helps makes direction finding practical.

When antennas are stacked for optimum forward gain the number of side nulls increases and they are not as deep. This gets worse with compromised stacking. I'd avoid stacking altogether in a situation where rejection was important. At these frequencys stacking is a whole lot of work. The rotor will get beat up. Not worth the hassle for under 3 dB IMHO. One could (as suggested) put up a quad and get about the same increase in forward gain as stacking with a given boom length.

Time energy and money could be used to put the proposed antenna higher and/or use lower loss cable as opposed to stacking.

<blockquote data-quote="HiDef" data-source="post: 137774" data-attributes="member: 7734">I try to think. Sometimes it works. Yes, cross polarization introduces about 20dB system loss. That was not the issue. The guy asked about verticals for local work. If he has problems with local QRM the answer is more in what he can notch out rather than maximum forward gain. A Maco 5 element yagi has very deep nulls at 90 degrees each side of the forward lobe. Point that at the offender and the signal will pretty much vanish. It also helps makes direction finding practical.When antennas are stacked for optimum forward gain the number of side nulls increases and they are not as deep. This gets worse with compromised stacking. I&#039;d avoid stacking altogether in a situation where rejection was important. At these frequencys stacking is a whole lot of work. The rotor will get beat up. Not worth the hassle for under 3 dB IMHO. One could (as suggested) put up a quad and get about the same increase in forward gain as stacking with a given boom length. Time energy and money could be used to put the proposed antenna higher and/or use lower loss cable as opposed to stacking.</blockquote>

[QUOTE="HiDef, post: 137774, member: 7734"] I try to think. Sometimes it works. Yes, cross polarization introduces about 20dB system loss. That was not the issue. The guy asked about verticals for local work. If he has problems with local QRM the answer is more in what he can notch out rather than maximum forward gain. A Maco 5 element yagi has very deep nulls at 90 degrees each side of the forward lobe. Point that at the offender and the signal will pretty much vanish. It also helps makes direction finding practical. When antennas are stacked for optimum forward gain the number of side nulls increases and they are not as deep. This gets worse with compromised stacking. I'd avoid stacking altogether in a situation where rejection was important. At these frequencys stacking is a whole lot of work. The rotor will get beat up. Not worth the hassle for under 3 dB IMHO. One could (as suggested) put up a quad and get about the same increase in forward gain as stacking with a given boom length. Time energy and money could be used to put the proposed antenna higher and/or use lower loss cable as opposed to stacking. [/QUOTE]

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