Topband: [PVRC] 2-element receiving arrays

Mon Apr 3 15:04:26 EDT 2023

It seems that padding the element capacitance as needed for equal
capacitance would help.

  Dave KH6AQ

On Thu, Mar 30, 2023 at 4:48 PM Frank W3LPL <donovanf at starpower.net> wrote:

> Hi Dave,
>
> Anyone who has experimented with a high impedance antenna such
> as an end fed half wave has experienced the extreme environmental
> influence on the feedpoint impedance of a high impedance feed.
>
> The required spacing to trees and buildings is very difficult to predict
> with any confidence. The impedance of a high impedance element
> -- and hence the amount of voltag if feeds into the preamp --
> is heavily influenced by its immediate environment.
>
> If all of the high impedance verticals in an array do not produce the
> same voltages from the signals received by the array, the pattern
> of the array and especially its nulls are significantly degraded.
>
> 73
> Frank
> W3LPL
>
>
>
>
>
>
>
> From: "K3ZJ David Siddall" <davek3zj at gmail.com>
> To: "Frank W3LPL" <donovanf at starpower.net>
> Cc: "topband" <Topband at contesting.com>, "PVRC" <pvrc at mailman.qth.net>,
> "Pete N4ZR N4ZR" <pete.n4zr at gmail.com>
> Sent: Friday, March 31, 2023 12:34:28 AM
> Subject: Re: [PVRC] Topband: 2-element receiving arrays
>
> Frank,
> " wrt to-negative effects of nearby trees and buildings." for high
> impedance verticals:
>
> Is there any data measuring how much loss if placed in the woods? Minimum
> distance from a tree to minimize the loss? Are their other effects too,
> such as less directionality?
>
> 73, Dave K3ZJ
>
>
>
> On Thu, Mar 30, 2023 at 1:38 PM Frank W3LPL < [ mailto:
> donovanf at starpower.net | donovanf at starpower.net ] > wrote:
>
>
> Hi Pete,
>
> For a monoband receiving array, you might consider using low impedance
> resonant verticals rather than high impedance verticals.
>
> The primary advantages of high impedance verticals are
> - very short verticals (but taller verticals produce stronger signals)
> - multi-band operation
> - no radials
>
> The primary disadvantages are
> - reliability issues with outdoor electronics
> - lightning susceptibility of outdoor electronics
> - higher cost
> - much lower signal levels
> - extreme care required to suppress common mode signals (buried feedlines
> are highly recommended)
> - negative effects of nearby trees and buildings.
>
> The primary advantages of low impedance verticals are
> - much stronger signal levels
> - much less criticality of common mode signal suppression,
> - much lower cost
> - much higher reliability
> - immunity to lightning damage
> - much less affected by nearby trees and buildings
>
> The primary disadvantages are
> - taller verticals (typically about 24 feet)
> - radials (they can be very short if many radials are used)
> - mono band operation (switchable matching networks can be used for
> multi-band operation).
>
> I highly recommend the DX Engineering Receiving Antenna Phasing System.
> Its expensive but well worth the investment especially for a small array.
>
> [ https://www.dxengineering.com/parts/dxe-ncc-2 |
> https://www.dxengineering.com/parts/dxe-ncc-2 ]
>
> If you have 120 feet for a three element array, the YCCC array is a great
> choice
> It can use high impedance or low impedance verticals
> Unfortunately its no longer available from DX Engineering
> The nine element YCCC array uses only three active elements at any time,
> so its really a three element array switchable in many directions.
>
> [
> https://static.dxengineering.com/global/images/instructions/dxe-yccc-switch.pdf?_gl=1*1cv0fc9*_ga*MjEyMDA1Nzc3MS4xNjUyMzAyMjc0*_ga_NZB590FMHY*MTY4MDE5NTk1OC40My4xLjE2ODAxOTYwNTYuNTAuMC4w
> |
> https://static.dxengineering.com/global/images/instructions/dxe-yccc-switch.pdf?_gl=1*1cv0fc9*_ga*MjEyMDA1Nzc3MS4xNjUyMzAyMjc0*_ga_NZB590FMHY*MTY4MDE5NTk1OC40My4xLjE2ODAxOTYwNTYuNTAuMC4w
> ]
>
> [ https://www.youtube.com/watch?v=dl-crM5Kb6A |
> https://www.youtube.com/watch?v=dl-crM5Kb6A ]
>
> [ https://www.youtube.com/watch?v=lVW1CmrzP7c |
> https://www.youtube.com/watch?v=lVW1CmrzP7c ]
>
> A two element array occupies only 60 feet or even a little less.
>
> 73
> Frank
> W3LPL
>
>
> ----- Original Message -----
> From: "Pete N4ZR N4ZR" < [ mailto:pete.n4zr at gmail.com |
> pete.n4zr at gmail.com ] >
> To: "topband" < [ mailto:Topband at contesting.com | Topband at contesting.com
> ] >
> Sent: Thursday, March 30, 2023 12:54:30 PM
> Subject: Topband: 2-element receiving arrays
>
> Thinking ahead to next winter on 160, I'm interested in replacing my
> K9AY Loop with a 2-vertical phased array. I'd like to homebrew the
> antennas and just buy or build the remote control unit for the shack.
> I'm looking for sources of components (antenna-located preamps and an
> in-shack controller), and would prefer not to completely homebrew them,
> but the prices at the usual suspects are awfully high. Any ideas?
>
> I have pretty reasonably-priced access to 25 and 31-foot fiberglass
> poles (used for wind-socks by model airplane enthusiasts). I'm thinking
> that one relatively low-cost approach might be to attach, say, #14 wire
> to the poles, with preamps at the base, but wonder if there is a
> downside to using such small-diameter antenna elements rather than 1 or
> 1.5 inch tubing? Alternatively, are clones of the DX Engineering 8'
> short verticals with preamps a good alternative?
>
> --
> 73, Pete N4ZR
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