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@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@contesting.com] On Behalf Of Jim
> Brown
> Sent: Saturday, August 08, 2015 11:23 AM
> To: topband@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)
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|