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Railfan Technology > Narrow beamwidth antennas.

Date: 01/31/19 16:15
Narrow beamwidth antennas.
Author: K3HX


This article is an introduction into narrow beamwidth (not narrow bandwidth)
antenna usage and how it can be used to reduce interference. 

Be Well,

Tim Colbert  K3HX

Edited 1 time(s). Last edit at 01/31/19 19:18 by K3HX.

Date: 01/31/19 19:04
Re: Narrow beamwidth antennas.
Author: wa4umr

Good article, Tim.  Thanks for posting.  


Date: 02/01/19 15:15
Re: Narrow beamwidth antennas.
Author: TCnR

Well written and interesting story.

I'm surprised they were assigned channels that were used so nearby, not sure why they would call that frequency coordination.

Date: 02/01/19 19:27
Re: Narrow beamwidth antennas.
Author: WW

A couple of things:  First, with regard to frequency coordination, it is important to remember that the railroad VHF frequency band only runs from 160.2150 mHz to 161.5650 mHz--not a big chunk of bandwidth.  Second, use of directional antennas is nothing new, especially for situations where the coverage needs to be more linear (as, for example, along a length of railroad or highway) versus coverage that is more areal (for example, covering an area within a town).  Where I work, all of our base station and repeater antennas are some flavor of directional antennas.  And, yes, proper installation and aiming of the antennas is important.

Date: 02/02/19 12:59
Re: Narrow beamwidth antennas.
Author: sptno

AAR, American Assocation of Railroad, Frequency Coordination is the designated Frequency Coordinator for the railroad frequencies, and is also certified for the General Business Pool.
I did radio frequency coordination in Texas when I worked for Texas Department of Transportation coordinating the frequcnies assigned to highway maintence operations.
South Austin, TX

Date: 02/02/19 13:13
Re: Narrow beamwidth antennas.
Author: TCnR

Plenty of channels inside that chunnk of bandwidth, why chose oones so close to other users? Important to use the same channel as an interagency effort, but this is for train dispatching and related use. Agree it's a better approach than using Omni antennas, usually there is a cost trade off with fewer or lower power transmitters needed. No need for an arguement.


Date: 02/05/19 17:20
Re: Narrow beamwidth antennas.
Author: JUTower

This was a timely and helpful article. Thank you.

Date: 02/08/19 16:47
Re: Narrow beamwidth antennas.
Author: CharlesVarnes

Does anyone know what the AAR Channels, or the frequencies are that TexRail is using?


Date: 02/12/19 12:16
Re: Narrow beamwidth antennas.
Author: Rick2582

Neat article, thank you, I missed that in the daily RailwayAge email post for some reason.

Nothing new, but interesting.

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