Topband: 2 Parallel Beverages

[donovanf at starpower.net]

The bidirectional Beverage antenna was patented by Harold Beverage in 1922: 

http://www.google.com/patents?id=oN5iAAAAEBAJ&printsec=abstract&zoom=4&dq=1434984#v=onepage&q=1434984&f=false

When Beverage built the huge RCA receiver site at Riverhead, Long Island, the Beverages were built as bidirectional Beverages used with a passive combiner with variable amplitude and phase to provide steerable deep nulls off the rear of the array.  This is described on page 221 of this seminal article published in 1923:

http://www.nrcdxas.org/articles/WaveAntenna.pdf

Perhaps the largest steerable phased Beverage array ever built was the four Beverage array at AT&T's transatlantic radiotelephone site in Houlton, Maine, straddling present day I-95 a few miles west of the Canadian border:

http://www.smecc.org/general_electric_computers/HoultonTelephone2.jpg

Far superior combiners are available to us today that much more easily provide steerable deep nulls, such as the DX Engineering NCC-1 Receive Antenna Variable Phasing Controller:

http://www.dxengineering.com/Parts.asp?ID=1227&PLID=215&SecID=114&DeptID={95EA549F-3210-474F-84E0-5BE0B267BC4C}&PartNo=DXE-NCC-1

73
Frank
W3LPL


---- Original message ----
>Date: Wed, 23 May 2012 15:46:56 +0100
>From: <g3pqa at onetel.com>  
>Subject: Re: Topband: 2 Parallel Beverages  
>To: "Jeff Woods" <jmwooods at yahoo.com>, <topband at contesting.com>
>
>Jeff,  EZNEC confirms what you and Neil have found.
>Modelling Neil G0JHC's antenna with 1000ft beverages at 12ft and 10ft, 
>offset by 30ft length-wise, shows almost identical patterns to a single 
>beverage.
>Terminating both ends of the unused bev improves the f/b as one might 
>expect, but does not appear to change the basic pattern.
>If you terminate both ends though, isn't it easier just to use one wire and 
>relay switch between the feeder and termination R?
>73
>John
>
>-----Original Message----- 
>From: Jeff Woods
>Sent: Wednesday, May 23, 2012 3:19 PM
>To: topband at contesting.com
>Subject: Re: Topband: 2 Parallel Beverages
>
>I missed the original post, but if the question pertains to running two 
>independent beverages in opposite directions on the same supports - Yes.  It 
>works well.
>
>
>I began doing this last winter, adding shorter, opposite direction beverages 
>to my NE and NNW (EU and JA) antennas.  Performance in the primary 
>directions is not compromised by any discernible amount.  The antennas are 
>completely independent, sharing only the PVC support mast.  The two 
>"secondary" antennas share a feed point (DC relay switched) where the two 
>primary antennas cross.  The two primary antennas were up and running before 
>the secondary directions were added. No changes in performanceof the primary 
>antennas was noted after the addition of the shared secondary wires.
>
>
>>From a theoretical point of view, this is no different than the operation 
>>of a typical 2-wire bi-directional array that relies on either wire working 
>>independently as a single-wire beverage in generating the common-mode 
>>signal.
>
>
>Jeff W0ODS
>Somewhere in Iowa
>
>
>
>>
>>>   For various reasons I am considering two single, parallel but 180deg 
>>> opposing direction beverages on the same supports rather than a single 
>>> switchable bidirectional beverage.  The bevs would be separated by 12 to 
>>> 18 inches or so. I've read that parallel bevs present performance 
>>> degradation issues but has anyone had any experience with this type of 
>>> setup versus the traditional bidirectional beverage? Thanks for reading 
>>> this and for any thoughts you could offer. 
>>> Mike  W2LO
>>
>>
>_______________________________________________
>UR RST IS ... ... ..9 QSB QSB - hw? BK 
>
>_______________________________________________
>UR RST IS ... ... ..9 QSB QSB - hw? BK