Topband: 8 circle: DXE vs Hi-Z

Tue Dec 16 16:15:53 EST 2014

Joel,
This will be very interesting when you can report some comparative results on both these good receiving antennas.

I am building - what I believe to be a somewhat novel antenna to try this season and hope to get it finished in early January.

Maybe someone considering a new receiving array might be interested?

The 4NEC2 models indicate that it will have a F/B on 160M of better than 50 dB and an RDF (thanks Tom for this measure) of about 11.9 dB. Its gain is calculated to be in the - 16 dB range. The modeling seems to be pretty robust - meaning that playing with the physical parameters does not dramatically change the calculated performance. In other words, I would be very suspect if a slight change in some input parameter totally destroyed the calculated performance results.

I comes by way of some further development of the SAL-30 Array (from Array Solutions) invented by Mark Bauman KB7GF. Larry Gauthier K8UT optimized the dimensions for the 160m band only.  I think Mark calls it the "High RDF CC-SAL (optimized for 160m)" array. It is 25 feet high and about 50 feet in diameter. The complete model showing all the algebra for the optimization (and dimensions) is readily available to all on the 'shared apex loop' reflector.

I'll let you know what I can about the performance - as soon as I can generate some numbers with my Kay attenuator pads.

73, Bruce W8RA

________________________________
 From: Joel Harrison <w5zn at w5zn.org>
To: topband at contesting.com 
Sent: Tuesday, December 16, 2014 9:42 AM
Subject: Re: Topband: 8 circle: DXE vs Hi-Z

Just to correct a typo, my HiZ 8 vertical array is spaced 200 ft, no 220 ft.

> Greetings Bob & Reflector folks,
>
> Please allow me to provide a bit of my experience since I run both a broad
> side/end fire passive 8 vertical array (350 ft diameter) with a DXE
> controller AND a HiZ 8 vertical array spaced for 160 meters (220 ft
> diameter).
>
> To your specific question about controllers both will perform very well
> but there are differences in the arrays that need to be considered, so
> please allow me a bit of bandwidth here to explain.
>
> I installed my BSEF array about five years ago when there was practically
> no avalable information about the array and no commercially available
> controllers. I built the array and a controller and published my work in a
> paper on my website that later was published in QEX.
>
> Since that time, I have gained a great deal of experience with the array
> both mechanically and eletrically and as a result of my published work
> others have built arrays (w3LPL for one) had have shared their valuable
> experience publically as well. As a result, I rebuilt my BSEF 8 vertical
> array this  year with a different mounting scheme like W3LPL uses and also
> moved to a better controller that Mike, W9RE first made boards available
> for and now that DX Engineering sells, which I now use for control of the
> BSEF array.
>
> Over this time Lee's HiZ arrays have become quite popular and are
> excellent performers. What I have noticed is there is considerable
> confusion among the masses about the differences in these arrays and to be
> quite blunt many folks equate living in an excellent geographical location
> for 160 meters propagation to amazing performance of a specific RX array
> which is an error. I am obsessed with 160 meter RX antennas and achieving
> peak performance from my rural location in central Arkansas, an area that
> is not enhanced by coastal propagation, etc. So I set out last year with a
> personal mission to evaluate both 8 vertical array systems, the passive
> BSEF array an the HiZ. I am not in the amateur radio business, I'm just a
> ham with a desire to have the best 160 meter RX system possible for my
> geographical area.
>
> So, both systems are operational here. There is significant sepeation
> between the two arrays (>800 ft) and both are a significant distance from
> the transmit antenna. Both have their own level of complexity with
> installation and from personal experience I can tell you they each take
> about the same amount of time to construct and install.
>
> I have already recorded several real on the air comparisons of patterns,
> noise floors (taking in to account one is active and one is passive)and
> several signal comparisons of DX stations (actual signal level about noise
> floor, not S meter readings). I plan to publish these results in early
> spring at the end of the 160 meter DX season for north america.
>
> I would be more than pleased to discuss any specific questions you may
> have about these arrays off line a bit more in detail if you would like
> but again the short answer to your question is both will be excellent
> arrays.
>
> 73 Joel W5ZN
>
>> I'm new to 160 and am planning to add an 8-circle. I would like to buy
>> commercial preamps and the controller. I would greatly appreciate any
>> advice on the choice of preamp/controller vendor.
>>
>> I live in a rural area and have a 4-direction 3-ele vertical array for
>> 160 with a 20+ dB f/b. So I'm looking for a beamwidth improvement on
>> receive.  Here are a couple questions:
>>
>> - Are the functions of the control network the same or similar between
>> DXE and Hi-Z? (so I could use either one?)
>>
>> - DXE wants a 320' diameter and Hi-Z wants 200' for optimum performance.
>> It's hard to tell what DXE performance is because it does not disclose
>> RDF, beam width or F/B. And neither vendor supplies EZNEC files so I can
>> see the effect of varying the layout. So I'm not sure how to decide what
>> array size is best for me. It would be wonderful if someone has a model
>> for these two systems.
>>
>> - If I use DXE, is it a no-brainer to use 24' verticals instead of the
>> shorter supplied whips?
>>
>> - are there any best practices for weatherproofing the Hi-Z components?
>>
>> - are there any build-quality differences between the two that I should
>> consider? I live in MT, so it is a harsh environment.
>>
>> Thanks!
>>
>> Bob, N7IP
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>>
>
>
> www.w5zn.org

>
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