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 <[email protected]> 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:[email protected]] On Behalf Of Jim > Brown > Sent: Saturday, August 08, 2015 11:23 AM > To: [email protected] > 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
