Topband: [Bulk] Best wire antenna for roof top location

[Merv Schweigert]

I have been in Jakarta and also a number of places in China trying to 
operate
from a city environment,  you cannot believe the noise, S9 if your 
lucky,  and its
360 degs, impossible to null,
Operating from BY1QH building top, the best was a dipole stretched 
between two buildings roofs.
At times the noise would go below S9,  was there two weeks trying to 
pull 160
signals out.
If you have never been there and heard that, its hard to grasp. Putting 
out a
signal was never a problem, hearing any one was.

We complain about plasma TV noise and other noise from Chinese made 
appliances
just think of trying to operate in the center of 5 or 10 million of 
these devices all around
you, and an the same care taken for the infrastructure of electric lines 
etc,  coated
with coal and smog dust and pollution, arcing at every juncture.
I bet the space station can hear the "buzz" on their electronics as they 
pass over
these areas.

73 Merv K9FD/KH6

> If the noise level is too high, perhaps you could use a separate receive
> antenna.
>
> A pennant, flag, or coaxial loop, might help null noise from certain
> directions.
>
> Art NK8X
> ᐧ
>
> On Sat, Aug 8, 2015 at 6:18 AM, Nuradi <yb0unc at gmail.com> wrote:
>
>> Thankyou verymuch to Grant KZ1W, Greg ZL3IX, Mike W0BTU, Garry NI6T and Jim
>> K9YC for all the suggestion.
>>
>> As suggest by Grant KZ1W and Jim K9YC, I will install a half-lambda dipole
>> on 160M with both ends were 90 degrees bent due to the size of the building
>> ,and find out what will be the Tx / Rx performance...
>>
>> To Mike W0BTU, it is slightly difficult to install the radial for the
>> vertical antenna or inverted L as
>> the roof top is not empty flat, hi hi
>>
>> Regards,
>> Nuradi, YB0UNC / KU2B
>>
>>
>> -----Original Message-----
>> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Jim
>> Brown
>> Sent: Saturday, August 08, 2015 11:23 AM
>> To: topband at contesting.com
>> Subject: Re: Topband: [Bulk] Best wire antenna for roof top location
>>
>> And remember -- the roof of this building is 110m, so a horizontal
>> antenna is high enough to have pretty good low angle radiation!  See
>>
>> http://k9yc.com/VertOrHorizontal-Slides.pdf  and double the heights for
>> the graphs of 80M performance.  When you're thinking height, consider
>> the building a tower -- it's mostly the far field reflection that
>> determines the vertical pattern.
>>
>> As to "ground" for a vertical antenna -- let's not confuse the word
>> "ground" with counterpoise or "radial system." An end-fed current-fed
>> vertical needs a counterpoise or radials, NOT a connection to earth.
>>
>> I strongly concur with the advice to spend some serious time LISTENING
>> on that roof before doing anything else.  It's pretty common for the
>> stuff described on that roof to be MONDO NOISY, and it's unlikely that
>> you can do much about most of it unless the guys who maintain it are HF
>> hams.
>>
>> 73, Jim K9YC
>>
>> On Fri,8/7/2015 8:02 PM, Garry Shapiro wrote:
>>> And Bob Brown used a monograph by J.A. Ratcliffe--"The Magneto-Ionic
>>> Theory and its Application to the Ionosphere" which says the same
>>> thing. It has to do with the angle between the E vector and the
>>> Earth's Geomagnetic Field, which is horizontal at the geomagnetic
>>> equator. Bob borrowed my copy of the book when he was writing the Big
>>> Gun's Guide.
>>>
>>> Garry, NI6T
>>>
>>> On 8/7/2015 6:24 PM, Greg - ZL3IX wrote:
>>>> Careful Mike! Jakarta is close to the equator, and power coupling is
>>>> likely to be better from a horizontally polarised antenna, especially
>>>> in an E-W direction.  Ref The Big Gun's Guide to Low-Band Propagation
>>>> by Bob Brown, NM7M (SK)
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