Topband: Hi-Z 160M 200' 8 Circle

[John Harden, D.M.D.]

I have a Waller Flag on a 40 foot boom at 95 feet that I use in 
DIVERSITY RECEIVE with a Hi-Z 8. It 's amazing to see how propagation 
changes from vertical to horizontal and back as time goes by... I have 
never heard this well...

73,

John, W4NU, Atlanta

K4JAG (1959 to 1998)


On 10/30/2017 12:20 PM, Doug Turnbull wrote:
> Dear Friends,
>
>   
>
>          Last night was again an interesting time to listen to TB.    I am
> now pretty sure that the 8 circle will under the right circumstances
> delivers a 30 dB Front to Back Ratio.    The F/B can drop to about 22 dB as
> well with 25 dB being most commonly observed.   It all depends on whether
> the signals is strong enough to still be above the noise after this amount
> of attenuation; what the noise floor itself is doing; beam heading and of
> course the angle at which the signal is arriving.    I can tell you that the
> beam pattern is amazingly sharp especially when you consider this is top
> band.    I have seen up to 20 dB drop in a signal just by turning the
> bearing 45 degrees.   Sometimes if I turn another 45 degrees the signal
> remains the same, lowers or even goes back up two or three dB - this is to
> be expected.   Imagine the help this is in a contest reducing QRM from
> adjacent stations.
>
>   
>
>          Having said all of this, the eight circle can not change band
> conditions.    I have yet to hear JA but no one close by is working them
> either.   I did hear Greenland working a string of JA stations but both
> countries were on the grey line at the time.    I tried to copy HL5IVL (call
> ?)for hours last night, but though I knew Kim was there and heard odd bits
> from him he was too weak to call.   Yet some EU stations including LA were
> working him with some stations reporting 59 on the cluster.    Now I have
> worked Kim many times in the past even copying reasonably well on the
> inverted L TX antenna.   Still this is frustrating but I suppose it is also
> 160M.
>
>   
>
>           Saturday night, I was copying JT5DX with a true 57 signal through
> all the EU noise on SSB.   He was great copy with me and I had to do this
> through a contest with splatter and many stations calling on his frequency
> as this is CQWW.   So I copy JT on SSB but not HL on CW.   Top band makes
> you work for it.    No doubt as the season progresses the JAs will be there
> and I hope to work many.   When I had an 800 foot Beverage on JA there were
> many winter evenings when I could not copy JA.
>
>   
>
>           It is hard to fully evaluate the Hi-Z 200' 160M 8 circle but my
> impression is that it is significantly (74 degree lobe vs 52 degree lobe)
> more directive than the previous 160 and 80 meter 114' foot diameter 8
> circle.   The pattern is sharper and deeper.    I do copy many signals with
> this antenna which can not be copied with the TX antenna.   The noise level
> drops from S4/5 to S0/1 when going from 160M inverted L (100' ft vertical
> run) to the 160M only 8 circle.    Signals also drop but again I copy
> signals even in the clear with the 8 circle which can not be heard with the
> TX antenna.   I have seen comparisons between this 8 circle and a 5 element
> Yagi - they are not the same type of antenna and this comparison is a bit
> "hoaky" but I can see the essence of it.
>
>   
>
>            On Saturday night there was an unusual high level noise from the
> south and boy was it handy to be listening in a more northerly direction as
> then this noise just dropped out.
>
>   
>
>             I think that sometimes too much attention is paid to the RDF
> factor of the RX antenna and not enough to directivity. You can model RDF
> but testing is another matter.  Yes RDF and directivity are related but they
> are not the same.   In a contest or when trying to work a DX station
> operating simplex; the directivity is a great help.    Of course as
> mentioned above it is also a help when nulling noise from a given direction.
>
>   
>
>             I am still waiting for a local friend to run tests at different
> times of the day for directivity with.    It would be helpful to get a
> better idea of the front to back.
>
>   
>
>             Presently a 80/40 meter Hi-Z interlaced (two four squares rather
> than all 8 elements active simultaneously) 8 circle with delay optimized for
> 40 meters is being assembled at 120 feet distance from the 160M 8 circle.
> According to Lee KTJR, this is more than adequate separation for the two
> antennas.   This antenna also works on TB so when completed there will be
> yet another report.
>
>   
>
>             Unfortunately I went to the scratcher too early last night to
> catch the 3C1.
>
>   
>
>                                                          73 Doug EI2CN
>
>   
>
>   
>
> _________________
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