"" A similar observation was made 20 years ago by Brian Beezley, K6STI, in a QST article titled "A Receiving Antenna that Rejects Local Noise" (September, 1995, page 33): I've been looking around for something that might work better than my present antenna, and I see good reports about the Waller flag from people who are actually using it. So I'll give it a try and see how well the theory matches up with actual practice. That's what ham radio is all about -- no? >>>>
Here one of the last understood subject on radio and antenna work, most of all paper about antenna. RF and propagation on MF and low band are valid only for vertical signals. For horizontal signal there is a major difference in the way Fields interact with Matter. If are an Engineer or someone that wants to give a try I recommend the book Electromagnetic Waves and Radiation Systems Edward C Jordan and Keith G Balmain page 277 Chapter 9 and 372 Chapter 11 Antenna fundaments. There is no horizontal signal near the ground, there is no ground waive or surface waive near the ground. So any or all manmade noise only can propagate by vertical surface waive or ground waive. Increasing the directivity of the RX antenna you can increase signal do noise ration my the same directivity gain. However is you turn the antenna horizontal the attenuation on vertical propagated noises is huge!. A low dipole on 160m,as example, does not receive any horizontal signal!, the only useful signal arrives vertical in the direction of the wire, same case of beverage antenna. Check the excellent article by Kai KE4PT on QEX and QST about best high for horizontal antennas. You will see that near the ground the attenuating is severe near 4 decay's. http://www.arrl.org/files/file/QEX_Next_Issue/May-Jun_2011/QEX_5_11_Siwiak.p df Using the antenna as polarization filter is the only solution to increase signal do noise ratio in urban areas. PY2XB lives downtown S Paulo, Fred is using WF for low bands and when he detunes his inverted V the noise on the WF drops 2S unis on 80m. Tom is right about the 40 db gain, gain means nothing, the NF of the system is the only thing the matters. Decrease your RF gain and increase the AF gain that you will hear better than most preamp's can help. N4IS JC _________________ Topband Reflector Archives - http://www.contesting.com/_topband
