Topband: Enlargement of TopBand Weapons

[Jarda OK1RD]

Dear TopBanders,
thanks to very mild winter here in the Central EU I was able to extend my
antennas systems for 160m band. As mentioned on this pages before I
had been having in use for whole year ( not only season as many others
topbanders ) 12ve Beverages antennas in star configuration and since 2005 a
full sized dipoles 4SQR phased (0)-(-137)-(-263) deg.. I am satisfied with
these antennas performance, the 4SQR mainly, which is listening unbelievably
well and always batten down with ETO91b my vertical and Henry 8K in Txing.
Nevertheless my ( our ?) topband obsession  forced me to build an 8 Circle
for the 160 band. Another reason for building of this new antenna system was
further incidentally reduce my Beverages field if you imagine that Beverages
are spread on 50ha and my joints are not so good as used to be Hi Hi Hi and
mainly to try a new Rxing system which I knew in little different
modification since 70th of last century when as young telecommunication
engineer was designing a special reception antenna for monitoring " enemy "
during cold war Hi. 
Thanks to Tom W8JI who refreshed my memory I built 8 Circle so soon that was
able to catch late ( spring ) topband season to let me test and compare
antennas systems. I would like to share my experience with you here.
First of all there are no miraculous antennas in the world at all. Just
bad,average, good and excellent antennas exists. 
My 8 Circle is designed as Rxing antenna only but so heavy duty that can be
changed to both Rxing and Txing 8 Circle very simply by changing emitters
and adding radials. The one is designed for side-by -side separation 0,65wl
e.g. Circle diameter 116m and end fire cells of 45m each. 
There are radiators 6m high with 2x10m hat. Each element has 6x radials 40m
long each plus 2x20m under elements hats. A lot of tests after I used for
each element specially alloyed pipe which has very very low conductivity (
my locksmith nearly killed me because he was not able to weld one without
special  atmosphere ). But I have got an excellent behaved element and then
adding just a few Ohms to reach 75Ohms output impedance and exactly tuned
one in real Rs between 1500 to 2500 kHz. The feeding coaxial cables are
special earthy construction 75 Ohms of course and 3/4 wl each. This is most
effective connection but makes usable bandwidth of the antenna system
between 1810 to 1860 kHz only. It was short system description only and more
results of my research will appear on my pages www.ok1rd.com soon.
My finding from real running of Beverages, 4SQR and 8Circle.
As motioned above no antenna is ideal. The 8 Circle is an excellent
performer thanks to very very narrow  beam one has essentially lower
background noise
And directivity surprised me because is much narrower than my 400m long
Beverages and on the level of my only one phased Beverages system with 90m
separation but noise still was lower from 8 Circle. As far as F/B there is
no comparison between the 8 Circle has very very deep F/B ( cca 35dB )
compare to Beverages with about 17dB.  The side attenuation of the 8 Circle
is almost nameless. 
I must mention that in the line a lot of comparisons there were cases when
reception from Beverages was better in certain period of the reception and
even my Txing 4SQR a few times listened better then 8 Circle or Beverage.
Nevertheless having these four listening weapons ( 4SQR,Beverages, 8Circle
and low dipole ) allowing me select some of them and I did not lose any DX
on the topband from the time of using all of them. My score on the top is
not so bad and hope will be better soon. The score is not so important for
me more joyance is bringing me building powerful antennas successfully with
the best performance of ones.
Thanks for reading my article up to here. Let me make a note, please do not
waste time and money to follow me if one do not have large open space for
building 8Circle. This antenna is very sensitive for surrounding object. I
had to chap down one  tree which was not very far from 8 Circle. Also my
Land Rover
parking close of one element made my headache because I was not able to tune
element properly Hi.   
By the way all the devices for remote controlled QTH are now developed based
on my demands and commercial available.  Since now building a  remote
controlled QTH is very simple task and all works very reliable. All devices
will be introduced in Friedrichshaffen.

Nice summer to all and antennas builders mainly
73 Jarda OK1RD/OK7XX