[Top] [All Lists]

Re: [TowerTalk] Turned reflector?

Subject: Re: [TowerTalk] Turned reflector?
From: Jim Brown <>
Date: Sun, 16 Sep 2012 14:04:02 -0700
List-post: <">>
On 9/16/2012 1:39 PM, Steve Hunt wrote:
The Forward Gain dropped by 0.3dB. The rearward pattern was badly affected: all the nulls were "filled in" as Jim suggested, and rearward lobes were typically 8dB higher.

Expanding on this a bit, this result is common to nearly all designs that produce directivity -- forward gain is produced by in-phase addition, so small changes in any element have a relatively small effect, but nulls are produced by the cancellation of two (or more) signals that are nearly equal and nearly 180 degrees out of phase. The more precise the equality, the greater the depth of the null, and relatively small differences in the signals producing the cancellation can fill in the null.

73, Jim K9YC

TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>