Re: Topband: Location of WF RX Antenna. Need Expert Advice
It depends not only on distance. Also the gain of both (TX- and RX) antennas matters. The lower the gain of the RX antenna, the more the re-radiating TX antenna (or other nearby wires/towers) will modify its pattern. Low gain loops, such as the Waller flag, are more critical compared to beverages. One of my beverages runs 5 meters from my TX antenna, and is useless without detuning the TX antenna. The other beverage has its feedpoint at 40 meter distance and runs away from the TX antenna and the influence is minimal. My advice: allways check the interaction by detuning the TX antenna(s). Use an AM broadcasting station as reference. Kees, PE5T Verzonden vanuit Mail voor Windows 10 Van: W0MU Mike Fatchett Verzonden: dinsdag 31 juli 2018 00:29 Aan: topband@contesting.com Onderwerp: Re: Topband: Location of WF RX Antenna. Need Expert Advice Interesting. My rcv array is probably 500 ft from the Xmit antenna or any antenna so I am probably ok? My 70ft tower is 70ish feet from the 160 inverted l. I wonder if there is much to be gained by attempting to detune the tower. W0MU On 7/30/2018 10:44 AM, Pete Rimmel N8PR wrote: > Joe, > > You might consider that there is interaction of the Waller Flag and > the other two towers as well as your transmit antenna while on receive. > > I suggest that you detune both of the other towers, as well as the > transmit antenna while using the WF on receive to eliminate them > re-radiating noise to the WF. > > Take a look at my YouTube video entitled: "N8PR TX Antenna > Construction and Detuning effects on receive Noise" > > https://www.youtube.com/watch?v=sk6PVl7uaBM&t=257s > > I think that you will see that the detuning is worthwhile. > > 73, PeteR N8PR > -- > > 1. Location of WF RX Antenna. Need Expert Advice > > {{I am hoping to construct a Waller Flag RX antenna on a 56' Heights > aluminum tower for 80 and 160M RX. The ideal location from aesthetic, > RF and maintenance-of-a-civil -family-climate standpoints is midway > (150' separation) between two existing LM-470 towers now separated by > about 300'. One has a 4-element Steppir and a 13-element 2M yagi on it > and the other a 2 element 30/40M quad. Obviously, the WF would not be > used simultaneously as the two existing antennas, and the Heights tower > would be well grounded.. Am I asking for a round of battles of trying > to mitigate interaction problems on either TX or RX on any of the bands > involved? Would an easy answer to my question be obtained from an EZNEC > simulation, especially since I already have models of the two current > antennas? > > I suspect other people on this reflector have been here before. I'd > appreciate any practical advice. > > > Many thanks and 73, > > Joe > K2XX}} > > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Location of WF RX Antenna. Need Expert Advice
I've just recently been reading up on Waller Flags, and am certainly no expert, but my impression so far is that an HWF (horizontally polarized flag), mounted up in the air on a tower, should be less affected by tall vertical thingies in the area; and less prone to local noise in the area which is normally vertically polarized, all of which is a major attraction of the antenna. So if your nearby horizontal items are not long ones in terms of wavelength on the frequencies of interest using the flag, I wouldn't expect a problem. If your plan is a vertically polarized flag, than ignore the previous comments. -Steve K8LX On 7/29/2018 6:58 PM, Joe Giacobello, K2XX via Topband wrote: I am hoping to construct a Waller Flag RX antenna on a 56' Heights aluminum tower for 80 and 160M RX. The ideal location from aesthetic, RF and maintenance-of-a-civil -family-climate standpoints is midway (150' separation) between two existing LM-470 towers now separated by about 300'. One has a 4-element Steppir and a 13-element 2M yagi on it and the other a 2 element 30/40M quad. Obviously, the WF would not be used simultaneously as the two existing antennas, and the Heights tower would be well grounded.. Am I asking for a round of battles of trying to mitigate interaction problems on either TX or RX on any of the bands involved? Would an easy answer to my question be obtained from an EZNEC simulation, especially since I already have models of the two current antennas? I suspect other people on this reflector have been here before. I'd appreciate any practical advice. Many thanks and 73, _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Location of WF RX Antenna. Need Expert Advice
On 7/30/2018 3:29 PM, W0MU Mike Fatchett wrote: Interesting. My rcv array is probably 500 ft from the Xmit antenna or any antenna so I am probably ok? My 70ft tower is 70ish feet from the 160 inverted l. I wonder if there is much to be gained by attempting to detune the tower. W0MU 500 feet is only 1 wavelength on top band. Interaction is entirely possible at that distance. Two verticals spaced 1/2 wavelength is a commonly used directional array design. Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Location of WF RX Antenna. Need Expert Advice
Interesting. My rcv array is probably 500 ft from the Xmit antenna or any antenna so I am probably ok? My 70ft tower is 70ish feet from the 160 inverted l. I wonder if there is much to be gained by attempting to detune the tower. W0MU On 7/30/2018 10:44 AM, Pete Rimmel N8PR wrote: Joe, You might consider that there is interaction of the Waller Flag and the other two towers as well as your transmit antenna while on receive. I suggest that you detune both of the other towers, as well as the transmit antenna while using the WF on receive to eliminate them re-radiating noise to the WF. Take a look at my YouTube video entitled: "N8PR TX Antenna Construction and Detuning effects on receive Noise" https://www.youtube.com/watch?v=sk6PVl7uaBM&t=257s I think that you will see that the detuning is worthwhile. 73, PeteR N8PR -- 1. Location of WF RX Antenna. Need Expert Advice {{I am hoping to construct a Waller Flag RX antenna on a 56' Heights aluminum tower for 80 and 160M RX. The ideal location from aesthetic, RF and maintenance-of-a-civil -family-climate standpoints is midway (150' separation) between two existing LM-470 towers now separated by about 300'. One has a 4-element Steppir and a 13-element 2M yagi on it and the other a 2 element 30/40M quad. Obviously, the WF would not be used simultaneously as the two existing antennas, and the Heights tower would be well grounded.. Am I asking for a round of battles of trying to mitigate interaction problems on either TX or RX on any of the bands involved? Would an easy answer to my question be obtained from an EZNEC simulation, especially since I already have models of the two current antennas? I suspect other people on this reflector have been here before. I'd appreciate any practical advice. Many thanks and 73, Joe K2XX}} _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Location of WF RX Antenna. Need Expert Advice
Joe, You might consider that there is interaction of the Waller Flag and the other two towers as well as your transmit antenna while on receive. I suggest that you detune both of the other towers, as well as the transmit antenna while using the WF on receive to eliminate them re-radiating noise to the WF. Take a look at my YouTube video entitled: "N8PR TX Antenna Construction and Detuning effects on receive Noise" https://www.youtube.com/watch?v=sk6PVl7uaBM&t=257s I think that you will see that the detuning is worthwhile. 73, PeteR N8PR -- 1. Location of WF RX Antenna. Need Expert Advice {{I am hoping to construct a Waller Flag RX antenna on a 56' Heights aluminum tower for 80 and 160M RX. The ideal location from aesthetic, RF and maintenance-of-a-civil -family-climate standpoints is midway (150' separation) between two existing LM-470 towers now separated by about 300'. One has a 4-element Steppir and a 13-element 2M yagi on it and the other a 2 element 30/40M quad. Obviously, the WF would not be used simultaneously as the two existing antennas, and the Heights tower would be well grounded.. Am I asking for a round of battles of trying to mitigate interaction problems on either TX or RX on any of the bands involved? Would an easy answer to my question be obtained from an EZNEC simulation, especially since I already have models of the two current antennas? I suspect other people on this reflector have been here before. I'd appreciate any practical advice. Many thanks and 73, Joe K2XX}} _ Topband Reflector Archives - http://www.contesting.com/_topband