Topband: New 160M high performance receiving antenna at W3LPL

Wed Feb 6 01:36:39 EST 2013

Hi Gary,

The University of Illinois research array in Bondville, Illinois was unique, it used one hundred elements distributed equally around a 1000 foot diameter circle.  It was the first Wullenweber array built in the U.S.

The approach taken in the USSR was quite different, instead of developing a next generation Wullenweber they installed more than one hundred nearly exact copies of the German World War II Wullenwever array.

Wullenweber arrays and their radial systems disturb about 30 acres of acres of land usually in rural areas, leaving a long lasting distinctive circular imprint on the landscape.  Traces of hundreds of Wullenweber arrays remain to this day, the 55 year-old Bondville array is no exception.

https://maps.google.com/maps?q=40.0494%C2%B0N,+88.3807%C2%B0W&hl=en&ie=UTF8&ll=40.049398,-88.380697&spn=0.003236,0.006968&sll=38.804821,-77.236966&sspn=3.373021,7.13562&t=h&z=18

The AN/FRD-10 and AN/FLR-9 arrays had their roots in research at Bondville in the 50s and 60s.  Both the AN/FRD-10 and the AN/FLR-9 were designed and built as dual use arrays.  They used a spinning electro-mechanical goniometer for fast and accurate DF measurements and rack-upon-rack of multicouplers feeding bank-upon-bank of fixed beamformers to produce many dozens of narrow beamwidth and sector beams feeding a hundred receivers (in some cases many more).

Soon after I moved to Maryland in the 1960s, the U.S. Navy moved its NSS HF receiver site from its RFI polluted Cheltenham, Maryland receiver site to Sugar Grove, West Virginia, now part of the National Radio Quiet Zone.

http://en.wikipedia.org/wiki/United_States_National_Radio_Quiet_Zone

The new Sugar Grove receiver site used a pair of AN/FRD-10 arrays feeding diversity receivers, to the best of my knowledge the only Wullenweber diversity array ever built anywhere in the world.  Even though the arrays were demolished more than 25 years ago, their huge foot print remains clearly visible from commercial airplanes flying southwest from Washington, D.C.

https://maps.google.com/maps?q=Sugar+Grove,+West+Virginia&hl=en&ll=38.513276,-79.278545&spn=0.006842,0.013937&sll=38.721948,-79.29657&sspn=0.873205,1.783905&oq=sugar+grove+West+Virginia&hnear=Sugar+Grove,+Pendleton,+West+Virginia&t=h&z=17

Regarding Wullenweber receiving sensitivity, it was (and continues to be) extremely difficult to design and build a high sensitivity, high dynamic range broadband HF receiver array especially with the vacuum tube and early solid state technologies available in the 1950s and 1960s.

Hams have it easy when we design high performance antennas: we're usually interested in specific narrow frequency ranges, specific azimuths and we typically feed only one or two receivers.  Its a totally different ballgame to design a high dynamic range, high sensitivity HF antenna system that provides continuous coverage from 1.5 - 30 MHz, instantly switchable narrow and broad beamwidths covering most if not all azimuths, and simultaneous feeds to hundreds of receivers (or more).  And it remains a non-trivial task with 21st century technology.  

The advent of high performance SDRs has made Wullenwebers obsolete but their imprint on the landscape will remain long after we've departed.

73
Frank
W3LPL

---- Original message ----
>Date: Tue, 05 Feb 2013 20:35:57 -0600
>From: Gary K9GS <garyk9gs at wi.rr.com>  
>Subject: Re: Topband: New 160M high performance receiving antenna at W3LPL  
>To: topband at contesting.com
>
>Or there's this one in Champaign, IL at the University of Illinois.
>
>http://www.ece.illinois.edu/about/history/wullenweber/index.asp
>
>It's been several decades since I've been out there and up close. In the 
>early 80s it was already in considerable dis-repair.
>
>
>On 2/4/2013 12:53 PM, donovanf at starpower.net wrote:
>> Hi Lee,
>>
>> You can save yourself lots of engineering effort if you simply make yourself a copy of this one:
>>
>> https://maps.google.com/maps?q=40+43+24+n,+141+19+44+e&hl=en&ll=40.72308,141.328892&spn=0.003313,0.006968&sll=40.723876,141.329155&sspn=0.026507,0.055747&t=k&z=18
>>
>> My former employer (then Sylvania, now General Dynamics Advanced Information Systems) installed it in 1966 at Misawa Air Base, Japan.  I believe its still exists, but its probably no longer in use due to technical obsolesence, high maintenance costs and unavailability of spare parts.  An identical array installed at Elmendorf Air Base, Alaska is also still in existence as far as I know.  Maybe you can purchase one of them!
>>
>> Many copies of the original 40 element German "Wullenwever" array were built all over USSR shortly after World War II, some may still exist.  Among other things, they tracked the 10 and 20 MHz Sputnik beacons that some of us recall.
>>
>> 73
>> Frank
>> W3LPL
>>
>> ---- Original message ----
>>> Date: Mon, 4 Feb 2013 10:13:55 -0800
>>> From: "Lee K7TJR" <k7tjr at msn.com>
>>> Subject: New 160M high performance receiving antenna at W3LPL
>>> To: "Robert McGwier" <rwmcgwier at gmail.com>, "Frank Donovan" <donovanf at starpower.net>
>>> Cc: "Topband" <topband at contesting.com>
>>>
>>>    Hello Bob and all, Yes I agree on the issue of needing the
>>>    stable impedance
>>>     from the elements to drive the passive systems. I still have
>>>    some questions
>>>     in my mind about the radials and here is why. I have made
>>>    many field tests
>>>     where I measured the actual phase and amplitude differences
>>>    between two
>>>     receiving elements where one is held constant and parameters
>>>    around the
>>>     other were changed such as ground rods, radials, and such.
>>>    Both were
>>>     receiving signal from an equidistant transmitted source.
>>>     What I can tell you
>>>     for sure about this is that with a Hi-Z system the phase and
>>>    amplitude shifts
>>>     become quite unstable when radials are used. I do not know
>>>    this to be a
>>>     fact with loaded elements but I have seen evidence of  some
>>>    received
>>>     signal shift due to the presence of the radials to the
>>>    element. This test really
>>>     opened my eyes about received signals and what objects might
>>>    affect
>>>     them. I have plans to buy the NEC4 engine and do some more
>>>    field tests
>>>     using another technology that should give me more answers. It
>>>    is these
>>>     minute details that prevent us from making these RX antennas
>>>    even smaller.
>>>      There is no doubt that the state of the art is advancing in
>>>    receiving antenas
>>>     with all the work that is and has gone on. I am confident
>>>    that what we are
>>>     presently doing is not perfect and I expect the state of the
>>>    art still has a ways
>>>     to go. There have been many man years of work by many people.
>>>    I hesitate
>>>     to name calls but a few notables are K6SE, W7IUV, W8JI, K9AY,
>>>    W3LPL,
>>>     W5ZN, W1FV, NX4D, N4IS, AA7J, K1LT and many many others that
>>>    I
>>>     apologize for not having the space here or personal memory at
>>>    the moment
>>>     to mention. There are more man years of work to do.
>>>        I still covet the 96 element Wullenwever antenna invented
>>>    around 1940!
>>>    Lee  K7TJR
>>>
>>>    >The issue is getting sufficient ground radials so that
>>>    changing soil conditions: dry season, wet season, etc have
>>>    minimal impact on the impedance which is the easiest
>>>    measurement of the changing conditions.  Joel and I did
>>>    measurements several times and when he was near drought he
>>>    found he had to add radials to stabilize the performance.
>>>     Once done, his system has been stable since.
>>>    Great news on both of you successfully deploying.
>>>    Bob
>>>    >N4HY
>>>
>>>
>> _________________
>> Topband Reflector
>>
>
>-- 
>
>
>73,
>
>Gary K9GS
>
>Greater Milwaukee DX Association: http://www.gmdxa.org
>Society of Midwest Contesters: http://www.w9smc.com
>CW Ops #1032   http://www.cwops.org
>
>************************************************
>
>_________________
>Topband Reflector