WIll add my two cents to this discussion. One thing I have experience with is diversity reception both on 160 and 80 meters. Often - I would be using my TX antenna in one ear and a beverage in another. On 80 meters, the TX antenna was a 4 square. On 160, either a vertical or two element phased array.
I found on 80 meters - when running JAs in a contest - if I only used one antenna - I would almost always miss one letter of the JA's callsign and have to ask for a repeat... but with diversity - the signal would float around in my head and I could almost always get the whole call the first time. I can hear this effect on 160 as well as signals float around. I can't prove this is just polarization - as it could be different angles of signal arrival - but it sure re-enforces the point that having different kinds of RX antennas for different situations is never a bad thing. I have experienced some sunrise openings where a low dipole has worked well. There are times when my directive receive antennas seem to be broken - which is another indication of high angles. Tree N6TR On Wed, Nov 28, 2018 at 8:51 AM Yuri Blanarovich <[email protected]> wrote: > Not knowing about "gyros", but when operating and having vertical and > horizontal antennas available, I remember times when QSB was happening > on one antenna, switching to the "other" polarization antenna would > bring the signals up. > My conclusion was that at the times the signal's polarization was > rolling around, especially when far DX. > > Yuri, K3BU, VE3BMV, VE1BY > > > On Wed, Nov 28, 2018 at 09:22 AM, Robert Parkes via Topband wrote: > > > > > Polarization on 160m > > > > Interesting discussion and one I suspect we wish could fully > > comprehend ! > > > > When the wave front meets the ionosphere and the wave splits the > > critical frequency is different for the two waves, commonly known as > > foc and fxc. > > This difference (from memory) is half the gyrofrequency and can often > > be seen on Ionosonde plots with two sets of reflections. The gyro > > frequency depends on the strength of the magnetic field at that point > > of the ionosphere so can vary from 700kHz to 1.4MHz where the radiated > > wave interacts with the Ionosphere Layer be it, E layer or F layer. > > > > Being radio amateurs and pushing the envelope we are trying to make > > that illusive QSO so we need to excite a propagation path which is > > normally at the limit in order to chase the DX. > > Assuming conditions are favourable, and if the angle of arrival and > > critical frequency is such that it favours both wave fronts then for a > > single and multi-hop transmission both the O-wave and the X-wave will > > be propagated. > > > > The higher frequency of the two wave fronts, the X-wave may propagate > > which could result in a QSO whilst those around us may not have quite > > the same favourable conditions and only the O-wave is propagated on a > > differeing path while the X-Wavecould fall by the wayside and not be > > propagated. > > One result of all this variability could result in what has been > > called spotlight or torchlight propagation. I recall Eric K3NA giving > > a talk along these lines when referring to 3B7C 160m operations and > > how that spotlight moved across North America during the course of his > > opening to the US. > > There is a possibility that Circular Polarisation would assist > > with both the O and X wave modes of propagation and it could be argued > > that a "compromise" Inv-L antenna provides this with its Vertical and > > Horizontal elements making up the antenna and resulting mixed > > polarisation.After all a number of amateurs have had good success with > > an Inv-L. > > > > 73sBob ParkesG3REP(ex - S21YP, 4S7RPG, A45XF, VS5RP, P29PR) > > _________________ > > Searchable Archives: http://www.contesting.com/_topband - Topband > > Reflector > > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
