Topband: Boradband noise on 160 meters tracked down to apartment complex
Mfj Nuller will not work because the signal is in the same direction of my 300 deg pointing pennant. My guess is that we should be able filter and shield properly at the source Don On Sunday, December 14, 2014, W2PM via Topband > wrote: > Sounds like a job for the MFJ nuller. The good news being its a point > source and should be easily handled. It may cost you several months of > frustration for no good outcome otherwise but perhaps it's worth a try if > there is a simple bonding issue there. > > Sent from my iPad > > > On Dec 14, 2014, at 01:08, Jim Brown wrote: > > > >> On Sat,12/13/2014 5:35 PM, Don Kirk wrote: > >> Now going back to the contractor that installed the equipment in an > attempt > >> to better understand the hardware in the unit > > > > That smells like a Variable Speed Drive, the heart of which is a > switching power supply that generates pulses in the 10 kHz range, the width > of which are varied to control the speed of the motor. Lots to go wrong > here -- switching power supply, square pulses of big current running a > distance between the controller and the motor, often with supply and return > conductors widely separated from each other, and with controller and motor > widely separated, so the current flows in a large loop. Can you say train > wreck? > > > > 73, Jim K9YC > > _ > > 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: Boradband noise on 160 meters tracked down to apartmentcomplex
Mfj Nuller will not work because the signal is in the same direction of my 300 deg pointing pennant. There are a lot of popular misconceptions about this. The noise does always not have to be a different direction, or even just one source. The MFJ nuller and other similar systems will remove noise when: 1.) The sense antenna is much closer to the noise, or picks up the noise much better compared to signals than the listening antenna does. This is true no matter what the desired signal direction. In this case you are eliminating a source by having a sense antenna hear the noise much stronger than the sense antenna hears desired signals. 2.) The noise is one or multiple sources from the same direction and the sense antenna is reasonably close to the RX antenna and the correct direction from the RX antenna. The noise has to be a significantly different direction than the RX direction. You are just eliminating the general noise direction in this case. 3.) The noise can be from multiple sources radiating from the same point. A long power line with multiple insulators arcing that is passing by close, and conducting emissions to that point, might be an example. You are nulling the point of coupling, rather than the noise generator's location. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Boradband noise on 160 meters tracked down to apartmentcomplex
Hi Tom, Thanks, and my statement was too broad. In my case I am unable to meet the conditions you mentioned (my sense antenna would not be much closer to the noise, and it would not pick up the noise much better than the listening antenna which is pointed in the direction of the noise source). Thanks as always, Don (wd8dsb) On Mon, Dec 15, 2014 at 10:08 AM, Tom W8JI wrote: > > Mfj Nuller will not work because the signal is in the same direction of my >> 300 deg pointing pennant. >> > > There are a lot of popular misconceptions about this. The noise does > always not have to be a different direction, or even just one source. > > The MFJ nuller and other similar systems will remove noise when: > > 1.) The sense antenna is much closer to the noise, or picks up the noise > much better compared to signals than the listening antenna does. This is > true no matter what the desired signal direction. In this case you are > eliminating a source by having a sense antenna hear the noise much stronger > than the sense antenna hears desired signals. > > 2.) The noise is one or multiple sources from the same direction and the > sense antenna is reasonably close to the RX antenna and the correct > direction from the RX antenna. The noise has to be a significantly > different direction than the RX direction. You are just eliminating the > general noise direction in this case. > > 3.) The noise can be from multiple sources radiating from the same point. > A long power line with multiple insulators arcing that is passing by close, > and conducting emissions to that point, might be an example. You are > nulling the point of coupling, rather than the noise generator's location. > > > _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: ground radials & conductivity
In Broadcasting, we used silver plating of tuned circuits often as copper oxide, depending upon the degree of oxidation, is a poor conductor, Silver oxide is a much better conductor than copper oxide. In the High powered short wave station that I worked. the ABB Swiss made transmitter plate tuning inductor was made of oxygen free copper, and water cooled. We used deionization resin beads to keep the water in good shape. One time as the water quality dropped we noted a shift in tuning that was traced to the water cooled Comet vacuum variable capacitors. Copper oxide, in the water, was causing a change in capatance. With Testing & research we found that copper oxide has stages of conductivity the last, black in color, is close to an insulator, that may act as a dielectric. Ground radials can suffer varying degree of copper oxidation depending, upon soil, electrolysis, and other factors. Covered wires can eventually have water intrusion. In the 1990's I used enameled coated wires, that have worked well so far. Electrical and thermal conductivity have a QUITE similar order of published metals. Electrical conductivity of metals http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/ Thermal conductivity of metals http://en.wikipedia.org/wiki/Copper_in_heat_exchangers Note: The backstay we found of the old 1920's Belfast radio station was galvanized iron. The galvanized surface was in good condition after so many years in the ground) In the aging process have wondered how Zinc oxide compared with copper oxide. (Copper-weld vs zinc coated electric fence wire) Zinc is not nearly as good to start with. 73 Bruce-k1fz www.qsl.net/k1fz/beveragenotes.html _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: ground radials & conductivity
Galvanized can be a problem in some soils. This is the reason that galvanized ground rods are no longer recommended in most applications (I think ON4UN even has a pictured of a rotted galvanized ground rod in his book). Copper-clad steel ground rods are more common and will generally hold up much better in typical soil conditions. I would assume the same would apply to galvanized steel and copper radial wires. I'd be careful using galvanized wire for radials without at first testing it to make sure it would last. It would be a shame to invest time and effort in a radial system just to see it rot away in a few years! -Bill KB8WYP > Note: The backstay we found of the old 1920's Belfast radio station was > galvanized iron. The galvanized surface was in good condition after so many > years in the ground) In the aging process have wondered how Zinc oxide > compared with copper oxide. (Copper-weld vs zinc coated electric fence > wire) Zinc is not nearly as good to start with. > > 73 > Bruce-k1fz > > www.qsl.net/k1fz/beveragenotes.html > > > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: ground radials & conductivity
Bill, The Back Stay rod was to show with correct galvanization of the 1920's they stood up well. The parentheses was a reference to wire used in antennas. I should have added "used in antennas". Reading down a little further: The ground wire information was to show that enameled copper wire stood up well in the ground as radials. 73 Bruce-k1fz www.qsl.net/k1fz/pennantnotes.html On Mon, 15 Dec 2014 16:20:57 , Bill Wichers wrote: Galvanized can be a problem in some soils. This is the reason that galvanized ground rods are no longer recommended in most applications (I think ON4UN even has a pictured of a rotted galvanized ground rod in his book). > > Copper-clad steel ground rods are more common and will generally hold up much better in typical soil conditions. I would assume the same would apply to galvanized steel and copper radial wires. I'd be careful using galvanized wire for radials without at first testing it to make sure it would last. It would be a shame to invest time and effort in a radial system just to see it rot away in a few years! > > -Bill KB8WYP > > > > Note: The backstay we found of the old 1920's Belfast radio station was > > galvanized iron. The galvanized surface was in good condition after so many > > years in the ground) In the aging process have wondered how Zinc oxide > > compared with copper oxide. (Copper-weld vs zinc coated electric fence > > wire) Zinc is not nearly as good to start with. > > > > 73 > > Bruce-k1fz > > > > www.qsl.net/k1fz/beveragenotes.html > > > > > > > > > > _ > > 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: ground radials & conductivity
Galvanized can be a problem in some soils. This is the reason that galvanized ground rods are no longer recommended in most applications (I think ON4UN even has a pictured of a rotted galvanized ground rod in his book). Galvanized is a problem here. In the air on in the ground, galvanized does not last long. My fence wire antennas last several years at the most, but the same wire goes away quickly in contact with soil. It is not just the soil type, but also electrolysis from ground currents that causes rapid decay issues. Copper-clad steel ground rods are more common and will generally hold up much better in typical soil conditions. I would assume the same would apply to galvanized steel and copper radial wires. I'd be careful using galvanized wire for radials without at first testing it to make sure it would last. It would be a shame to invest time and effort in a radial system just to see it rot away in a few years! There is far too much worry about copper oxide on HF (or lower) conductors. Other than showing a visual patina, effects are pretty meaningless at HF unless actually in a connection where current is forced through the oxide. I wouldn't worry a bit about using bare copper surface. I use galvanized fence wire, but it goes away fast if in earth contact. It marginally lasts long enough suspended in air, and it always has to be greased if it contacts stainless or metals other than things way off at the far anodic end of tables. To solve that with the headache of grease, a Teflon insulated wire downlead (which is usually silver flashed) or bare copper can be soldered to the fence wire (if you don't overheat the fence wire and burn off the galvanizing). Depending on the wire I might see ten years in air, sometimes as little as three or four, before a suspended wire needs replacement. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Followup on the 1915kHz radar signal
After some Googling and educated guessing, I have determined (and received confirmation of) the following: - It is a high-frequency surface-wave radar (HFSWR) system, developed by Raytheon Canada for the Canadian military. It seems to be a new version of the SWR503 MK2 HFSWR system. It is intended to detect ships up to 200 miles from a country's coast (EEZ) to protect against terrorists, smugglers, and unauthorized fishing vessels as well as locate vessels in distress. The present system has been detected at 1915, 3250, 4400, and 5300 kHz. - It is located at Hartlen Point, NS, near Halifax (point Google Earth to 44 35 29.47 N 63 26 49.68 W ) and if you zoom in you can see the 500M long cleared area for the towers and the guy anchors. - W1FV was pretty close with his estimate of a heading of 75 degrees (it is actually 67 degrees from John's QTH). - ARRL, RAC, and Industry Canada (Canada's FCC) have been made aware of the interference that this signal is causing to amateurs. - The frequency band 1850-2000 is a shared allocation in Canada, among amateur, radionavigation, and radiolocation services. - A previous version of this system was installed in several other regions. 1915 kHz is not the primary operating frequency for the system. The higher frequencies generally work better for the intended purpose. So the mystery is solved...at least as far as the source is concerned. 73, Doug K1DG _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Followup on the 1915kHz radar signal
Hi Doug, Thanks for the follow up. I was saying 70 to 75 degrees, and 70 degrees from my location puts me right where the W1FV 75 degree line passes below the location you have identified. Interesting stuff. Thanks, Don (wd8dsb) On Mon, Dec 15, 2014 at 12:42 PM, Doug Grant wrote: > > After some Googling and educated guessing, I have determined (and > received confirmation of) the following: > > - It is a high-frequency surface-wave radar (HFSWR) system, developed > by Raytheon Canada for the Canadian military. It seems to be a new > version of the SWR503 MK2 HFSWR system. It is intended to detect ships > up to 200 miles from a country's coast (EEZ) to protect against > terrorists, smugglers, and unauthorized fishing vessels as well as > locate vessels in distress. The present system has been detected at > 1915, 3250, 4400, and 5300 kHz. > > - It is located at Hartlen Point, NS, near Halifax > (point Google Earth to 44 35 29.47 N 63 26 49.68 W ) > > and if you zoom in you can see the 500M long cleared area for the > towers and the guy anchors. > > - W1FV was pretty close with his estimate of a heading of 75 degrees > (it is actually 67 degrees from John's QTH). > > - ARRL, RAC, and Industry Canada (Canada's FCC) have been made aware > of the interference that this signal is causing to amateurs. > > - The frequency band 1850-2000 is a shared allocation in Canada, among > amateur, radionavigation, and radiolocation services. > > - A previous version of this system was installed in several other regions. > > 1915 kHz is not the primary operating frequency for the system. The > higher frequencies generally work better for the intended purpose. > > So the mystery is solved...at least as far as the source is concerned. > > 73, > > Doug K1DG > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Boradband noise on 160 meters tracked down to apartment complex
I have done a little bit of research into the variable speed drive motors that are commonly part of "eco-friendly" green HVAC systems. I have found in many cases that the installer sells SEER-rated components as part of their most efficient packages, but in most cases the installation takes no advantage of the variable speed drive capabilities of the SEER-rated blower and compressor motors because they are wired up to work only at a single speed. In my particular case, my house's HVAC had a blower motor that failed. It was a $1100 SEER-rated variable speed blower motor. It was only 3 years old. It was only wired up to work at a single speed. I replaced it with a $200 capacitor-start motor. Tim N3QE On Sun, Dec 14, 2014 at 1:08 AM, Jim Brown wrote: > > On Sat,12/13/2014 5:35 PM, Don Kirk wrote: > >> Now going back to the contractor that installed the equipment in an >> attempt >> to better understand the hardware in the unit >> > > That smells like a Variable Speed Drive, the heart of which is a switching > power supply that generates pulses in the 10 kHz range, the width of which > are varied to control the speed of the motor. Lots to go wrong here -- > switching power supply, square pulses of big current running a distance > between the controller and the motor, often with supply and return > conductors widely separated from each other, and with controller and motor > widely separated, so the current flows in a large loop. Can you say train > wreck? > > 73, Jim K9YC > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Followup on the 1915kHz radar signal
Nice find, Doug, it sure is a strong signal. With my 3 el HI-Z I couldn't guess the direction in any real accuracy but I had a feeling from the stronger NE signals, it was NE & following the coastline from my QTH on the ocean in SE CT. Indeed NS is right in that line from here at 50 degrees north. Nice to know that the HI-Z is not only well directional but is seemingly oriented well. As far as the signal itself, the military obviously trumps the civilian needs and I guess we can be glad it doesn't drift around like the woodpecker did. 73, Gary, KA1J > After some Googling and educated guessing, I have determined (and > received confirmation of) the following: > > - It is a high-frequency surface-wave radar (HFSWR) system, developed > by Raytheon Canada for the Canadian military. It seems to be a new > version of the SWR503 MK2 HFSWR system. It is intended to detect ships > up to 200 miles from a country's coast (EEZ) to protect against > terrorists, smugglers, and unauthorized fishing vessels as well as > locate vessels in distress. The present system has been detected at > 1915, 3250, 4400, and 5300 kHz. > > - It is located at Hartlen Point, NS, near Halifax > (point Google Earth to 44 35 29.47 N 63 26 49.68 W ) > > and if you zoom in you can see the 500M long cleared area for the > towers and the guy anchors. > > - W1FV was pretty close with his estimate of a heading of 75 degrees > (it is actually 67 degrees from John's QTH). > > - ARRL, RAC, and Industry Canada (Canada's FCC) have been made aware > of the interference that this signal is causing to amateurs. > > - The frequency band 1850-2000 is a shared allocation in Canada, among > amateur, radionavigation, and radiolocation services. > > - A previous version of this system was installed in several other regions. > > 1915 kHz is not the primary operating frequency for the system. The > higher frequencies generally work better for the intended purpose. > > So the mystery is solved...at least as far as the source is concerned. > > 73, > > Doug K1DG > _ > Topband Reflector Archives - http://www.contesting.com/_topband > --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: ground radials & conductivity
Ah, sorry if I misinterpreted what you meant. Regarding "proper" galvanization, such things CAN still be had. There are two kinds of galvanized products these days: "flash" galvanized, which is usually not very useful outdoors, and "hot dipped" galvanized. The hot-dipped type tends to look "crusty" and dull gray in color but will hold up for decades. All the utility hardware is done this way and it lasts. You can get this type of galvanized hardware in big box hardware places, it will look dull gray (NOT shiny). A lot of the shiny stuff people think is galvanized is actually a cadmium playing and it rusts pretty quickly outdoors. -Bill > -Original Message- > From: k...@myfairpoint.net [mailto:k...@myfairpoint.net] > Sent: Monday, December 15, 2014 11:49 AM > To: Bill Wichers; Topband > Subject: Re: Topband: ground radials & conductivity > > Bill, > The Back Stay rod was to show with correct galvanization of the 1920's they > stood up well. > The parentheses was a reference to wire used in antennas. I should have > added "used in antennas". > Reading down a little further: > The ground wire information was to show that enameled copper wire stood > up well in the ground as radials. > 73 > Bruce-k1fz > www.qsl.net/k1fz/pennantnotes.html > > > > On Mon, 15 Dec 2014 16:20:57 , Bill Wichers > wrote: > Galvanized can be a problem in some soils. This is the reason that > galvanized > ground rods are no longer recommended in most applications (I think > ON4UN even has a pictured of a rotted galvanized ground rod in his book). > > > > Copper-clad steel ground rods are more common and will generally hold > up much better in typical soil conditions. I would assume the same would > apply to galvanized steel and copper radial wires. I'd be careful using > galvanized wire for radials without at first testing it to make sure it would > last. It would be a shame to invest time and effort in a radial system just > to > see it rot away in a few years! > > > > -Bill KB8WYP > > > > > > > Note: The backstay we found of the old 1920's Belfast radio station was > > > galvanized iron. The galvanized surface was in good condition after so > many > > years in the ground) In the aging process have wondered how Zinc > oxide > > compared with copper oxide. (Copper-weld vs zinc coated electric > fence > > wire) Zinc is not nearly as good to start with. > > > > > > 73 > > > Bruce-k1fz > > > > > > www.qsl.net/k1fz/beveragenotes.html > > > > > > > > > > > > > > > _ > > > 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: Followup on the 1915kHz radar signal
I believe 1900 to 2000 kHz is shared with radiolocation in the US also. I'm just thankful it's not on 1815!! 73, Roger _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: FW: Boradband noise on 160 meters tracked down to apartment complex
To add to what Jim had said about this "smells like a Variable Frequency Drive [VFD]" (which I also think is probably what you're seeing here): VFDs operate by varying the power to a three phase motor to control speed and torque. This is done through PWM (Pulse Width Modulation) at a frequency in the kHz+ range. They rely on the inductance of the motor windings to integrate the switching waveform into essentially a sine wave of varying voltage and frequency. Since the motor itself is part of the filter network, the wiring between the VFD and the motor can sometimes radiate. VFDs will commonly specify that the wiring between the drive and the motor be of no more than a specific length (which is usually relatively short such as 20-50 feet or so), and that it be in a *metal* conduit which helps with shielding. You should check that the cabling between the VFD and the motor was installed properly. The other possibility is that noise is coming from the supply lines (the normal AC supply wiring) to the VFD. This is probably less likely than the VFD-to-motor wiring, but it's something to check. You can get a "reactor" to use for helping with AC line distortion that might also help with reducing radiated noise if it's coming from the power wiring. The reactors are just small inductors that help to "round off" the switching transients produced by the rectifier in the VFD. Good luck in your worthy quest to eradicate some RFI! -Bill > -Original Message- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Don > Kirk > Sent: Saturday, December 13, 2014 8:35 PM > To: topband > Subject: Re: Topband: Boradband noise on 160 meters tracked down to > apartment complex > > Update on the apartment complex noise that I tracked down to a new > apartment complex in late October. > > Finally was able to meet with the maintenance manager for this > facility this past Thursday, and we were able to track the source of > the interference to an HVAC air handler unit located on the roof of > the complex. Once again used my portable HF receiver (without my > external > preamp) with 14" diameter tuned loop, and had to back the gain way > down on the receiver to locate the source. We were able to turn on > and off the unit and observe the RFI turn on and off as we turned the unit on > and off. > I then drove back to my house, and we ran the tests again and sure > enough the interference at my house was on when we turned the air > handler on, and RFI went away when the air handler was turned off. > > Now going back to the contractor that installed the equipment in an > attempt to better understand the hardware in the unit (hope to get > some prints, > etc.) before having them actually attempt to tackle the problem. > Fortunately I have a couple of years of HVAC experience from an > electrical controls standpoint (had to revamp a faulty design for our > manufacturing plant), and suspect this past experience will come in > handy during our investigation. > > Just FYI, > > Don Kirk (wd8dsb) > _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: 8 circle: DXE vs Hi-Z
I'm new to 160 and am planning to add an 8-circle. I would like to buy commercial preamps and the controller. I would greatly appreciate any advice on the choice of preamp/controller vendor. I live in a rural area and have a 4-direction 3-ele vertical array for 160 with a 20+ dB f/b. So I'm looking for a beamwidth improvement on receive. Here are a couple questions: - Are the functions of the control network the same or similar between DXE and Hi-Z? (so I could use either one?) - DXE wants a 320' diameter and Hi-Z wants 200' for optimum performance. It's hard to tell what DXE performance is because it does not disclose RDF, beam width or F/B. And neither vendor supplies EZNEC files so I can see the effect of varying the layout. So I'm not sure how to decide what array size is best for me. It would be wonderful if someone has a model for these two systems. - If I use DXE, is it a no-brainer to use 24' verticals instead of the shorter supplied whips? - are there any best practices for weatherproofing the Hi-Z components? - are there any build-quality differences between the two that I should consider? I live in MT, so it is a harsh environment. Thanks! Bob, N7IP _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Followup on the 1915kHz radar signal
From: Roger D Johnson > I believe 1900 to 2000 kHz is shared with radiolocation in the US also. > I'm just thankful it's not on 1815!! > 73, Roger That's correct. But the FCC has proposed to discontinue the radiolocation allocation in that frequency range, and return the entire band to amateurs as primary users, in an omnibus NPRM released two years ago. They said that at the time, there were no current licensees for 160m radiolocation in the FCC data base. Apparently, GPS has pretty well rendered MW roadiolocation obsolete, and use of the service is all but discontinued. Back in the 1980s and 90s there were a number of beacons operating in our band, and radiolocation interests expressed the intent to keep on expanding the service and threatened to eventually push us out, since the amateur allocation that part of the band is only on a secondary basis. The frequencies between the AMBC band and 160m used to be packed solid with beacons; now they are all gone and that spectrum is devoid of signals, and beacons are no longer heard in our band except for a few weak unlicensed fishnet buoys that can be heard sending out weak CW signals. Even those are of questionable legal status. At the time, the amateur community didn't pay much attention to the proposal, which was announced on the ARRL website. Most hams seemed to think it was much ado about nothing, since there weren't any radiolocation beacons left in our band anyway. I said back then that we should have flooded tthe FCC with comments in favour, since as long as we remain in secondary status, some new technology could come along any day and seek to operate in the top half of the band under the guise of "radiolocation". Apparently this is exactly the case with the Canadian radar system. Let's hope this radar system doesn't gain favour in the USA. Even if they aren't operating in the vicinity of 1815, this would be a dire threat to users in this part of the band, if hams are ever displaced from the top end. Activity now in the top end would have to be re-accommodated somewhere below 1900, greatly increasing congestion all the way down to 1800, hampering CW operation as well as weak-signal reception in the so-called "DX window". Don k4kyv _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Followup on the 1915kHz radar signal
Which does "radiolocation" mean? Radar or loran/GPS/etc. or both? Not obvious. Rick N6RK On 12/15/2014 11:56 AM, Roger D Johnson wrote: I believe 1900 to 2000 kHz is shared with radiolocation in the US also. I'm just thankful it's not on 1815!! 73, Roger _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Boradband noise on 160 meters tracked down toapartmentcomplex
Hi Tom Thanks for your comments in the email below. I have a 80m noise that is from a local house source and your comments below have me thinking about how to implement a vertical noise sense antenna. I believe the noise to be vertically polarized as my horizontal loop does not have the same noise receive issue as my 80m vertical does. Thus my plan was to set up a vertical antenna outside and connect it to my ANC-4 noise nulling system as the sense antenna. I currently used the ANC-4 with a wire strung in the basement with the target to null out plasma tv noise and this was reasonably successful until the new noise showed up. My current sense system does not hear the noise at all so something else needs to be set up. The vertical element I was going to use was a simple 102 inch whip, however based on your comment I am thinking a longer vertical element would be better but I am not sure how to pick a vertical length. I have concluded based on driving around this weekend with a simple direction loop that it is less than 1/2 mile away from me and its comes from a house. It was active this Sunday morning and using the simple loop I am confident that it is from a specific house. It is not power pole noise that is something that I recognize easily with my mobile operations. So specifically noise is 80m and I want to null it so I can use 80m again. My thought is a vertical sense antenna, my first thought was a 102 inch whip but I can make something longer. I know the direction of the noise so I can put the sense antenna where needed so I am open for suggestions. This was the noise that showed up and then disappeared and now has returned intermittently so I need to attempt to try and null it out. Cheers Don ~73 Don KD8NNU 2014 3905CC Top Gun :-) -.- -.. ---.. -. -. ..- -Original Message- From: Tom W8JI Sent: Monday, December 15, 2014 10:08 AM To: Don Kirk ; W2PM Cc: topband@contesting.com ; j...@audiosystemsgroup.com Subject: Re: Topband: Boradband noise on 160 meters tracked down toapartmentcomplex Mfj Nuller will not work because the signal is in the same direction of my 300 deg pointing pennant. There are a lot of popular misconceptions about this. The noise does always not have to be a different direction, or even just one source. The MFJ nuller and other similar systems will remove noise when: 1.) The sense antenna is much closer to the noise, or picks up the noise much better compared to signals than the listening antenna does. This is true no matter what the desired signal direction. In this case you are eliminating a source by having a sense antenna hear the noise much stronger than the sense antenna hears desired signals. 2.) The noise is one or multiple sources from the same direction and the sense antenna is reasonably close to the RX antenna and the correct direction from the RX antenna. The noise has to be a significantly different direction than the RX direction. You are just eliminating the general noise direction in this case. 3.) The noise can be from multiple sources radiating from the same point. A long power line with multiple insulators arcing that is passing by close, and conducting emissions to that point, might be an example. You are nulling the point of coupling, rather than the noise generator's location. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Followup on the 1915kHz radar signal
This might appear Canadian but it is US technology and US patents and it would be a small step to see it on US soil next. Paul, VE3TA On Mon, Dec 15, 2014 at 7:23 PM, Donald Chester wrote:From: Roger D Johnson > I believe 1900 to 2000 kHz is shared with radiolocation in the US also. > I'm just thankful it's not on 1815!! > 73, Roger That's correct. But the FCC has proposed to discontinue the radiolocation allocation in that frequency range, and return the entire band to amateurs as primary users, in an omnibus NPRM released two years ago. They said that at the time, there were no current licensees for 160m radiolocation in the FCC data base. Apparently, GPS has pretty well rendered MW roadiolocation obsolete, and use of the service is all but discontinued. Back in the 1980s and 90s there were a number of beacons operating in our band, and radiolocation interests expressed the intent to keep on expanding the service and threatened to eventually push us out, since the amateur allocation that part of the band is only on a secondary basis. The frequencies between the AMBC band and 160m used to be packed solid with beacons; now they are all gone and that spectrum is devoid of signals, and beacons are no longer heard in our band except for a few weak unlicensed fishnet buoys that can be heard sending out weak CW signals. Even those are of questionable legal status. At the time, the amateur community didn't pay much attention to the proposal, which was announced on the ARRL website. Most hams seemed to think it was much ado about nothing, since there weren't any radiolocation beacons left in our band anyway. I said back then that we should have flooded tthe FCC with comments in favour, since as long as we remain in secondary status, some new technology could come along any day and seek to operate in the top half of the band under the guise of "radiolocation". Apparently this is exactly the case with the Canadian radar system. Let's hope this radar system doesn't gain favour in the USA. Even if they aren't operating in the vicinity of 1815, this would be a dire threat to users in this part of the band, if hams are ever displaced from the top end. Activity now in the top end would have to be re-accommodated somewhere below 1900, greatly increasing congestion all the way down to 1800, hampering CW operation as well as weak-signal reception in the so-called "DX window". Don k4kyv _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Followup on the 1915kHz radar signal
Raytheon Canada Limited is a wholly owned subsidiary of Raytheon Company (NYSE:RTN), a 24 billion dollar technology leader specializing in defence, homeland security and other government markets throughout the world. With headquarters in Waltham, Mass., Raytheon employs 73,000 people worldwide. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 8 circle: DXE vs Hi-Z
- DXE wants a 320' diameter and Hi-Z wants 200' for optimum performance. It's hard to tell what DXE performance is because it does not disclose RDF, beam width or F/B. And neither vendor supplies EZNEC files so I can see the effect of varying the layout. So I'm not sure how to decide what array size is best for me. It would be wonderful if someone has a model for these two systems. Bob, The ideal spacing of arrays like this is entirely dependent on the frequency range and goal you have for pattern or directivity. It is NOT dependent on the design or manufacturer, there are no magical space saving tricks. The circle diameter determines both endfire and broadside spacing, and spacing determines the beamwidth. Something in the 330-350 foot range across the element pairs is near optimum for 160 directivity. You can use it down to spacings where the element-to-element spacing is about 35-40 feet on 160, but it might as well be a four element vertical or some other array at that spacing. You can narrow the 160 pattern by going larger than 350 feet, but the array can develop unwanted lobes. If element-to-element goes over 135 feet or so, you will start to have F/R issues. This is the way every single eight element circle will work. The primary difference between the DXE and Hi-Z is construction quality, and that determines cost. The DXE unit is a metal case that serves as a groundplane for the connectors, and a much better PC layout. How much that translates into better performance depends on how "pure" the rest of the installation is. If the installation is sloppy or compromised, that will set the limit more than construction. The DXE is a nearly direct copy of what I use here, which is a very clean layout with PC mounted connectors and a super good groundplane between connectors to prevent ground loops that affect performance and minimize chances of lightning damage. One reason I especially worry about connector grounding is my eight verticals are spread in around a 350ft circle, and each has several 70 ft buried radials. The large physical size of a system like this sets the system up for large common mode currents in storms, it is actually a yearly event here to melt the shields off at least one cable with a nearby lighting hit (within a few thousand feet) because of ground loop currents, and yet I almost never have box troubles. I use a 20ft vertical with a small loading coil and series load resistor in my elements, and a three wire hat. Mine is single band 160 (although I'm very slowly working on a 16-element circle for 160-80). People who operate here just love the 8 circle. I can send you an EZNEC file that would roughly approximate the array. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 8 circle: DXE vs Hi-Z
The primary difference between DXE and Hi-Z 8 circle arrays is the fact that Hi-Z uses ALL 8 verticals actively at the same time where DXE uses only 4 at a direction. Using all 8 verticals allows the use of a smaller diameter and a performance edge on Directivity over the larger 4 active array. All 8 element arrays do NOT work the same way. Lee K7TJR -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Monday, December 15, 2014 7:24 PM To: Bob Tabke; topband@contesting.com Subject: Re: Topband: 8 circle: DXE vs Hi-Z > - DXE wants a 320' diameter and Hi-Z wants 200' for optimum performance. > It's hard to tell what DXE performance is because it does not disclose > RDF, beam width or F/B. And neither vendor supplies EZNEC files so I > can see the effect of varying the layout. So I'm not sure how to > decide what array size is best for me. It would be wonderful if > someone has a model for these two systems. Bob, The ideal spacing of arrays like this is entirely dependent on the frequency range and goal you have for pattern or directivity. It is NOT dependent on the design or manufacturer, there are no magical space saving tricks. The circle diameter determines both endfire and broadside spacing, and spacing determines the beamwidth. Something in the 330-350 foot range across the element pairs is near optimum for 160 directivity. You can use it down to spacings where the element-to-element spacing is about 35-40 feet on 160, but it might as well be a four element vertical or some other array at that spacing. You can narrow the 160 pattern by going larger than 350 feet, but the array can develop unwanted lobes. If element-to-element goes over 135 feet or so, you will start to have F/R issues. This is the way every single eight element circle will work. The primary difference between the DXE and Hi-Z is construction quality, and that determines cost. The DXE unit is a metal case that serves as a groundplane for the connectors, and a much better PC layout. How much that translates into better performance depends on how "pure" the rest of the installation is. If the installation is sloppy or compromised, that will set the limit more than construction. The DXE is a nearly direct copy of what I use here, which is a very clean layout with PC mounted connectors and a super good groundplane between connectors to prevent ground loops that affect performance and minimize chances of lightning damage. One reason I especially worry about connector grounding is my eight verticals are spread in around a 350ft circle, and each has several 70 ft buried radials. The large physical size of a system like this sets the system up for large common mode currents in storms, it is actually a yearly event here to melt the shields off at least one cable with a nearby lighting hit (within a few thousand feet) because of ground loop currents, and yet I almost never have box troubles. I use a 20ft vertical with a small loading coil and series load resistor in my elements, and a three wire hat. Mine is single band 160 (although I'm very slowly working on a 16-element circle for 160-80). People who operate here just love the 8 circle. I can send you an EZNEC file that would roughly approximate the array. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Alert-Alert- Stew Perry Top Band DX Challenge is Coming
Greetings to 160M Contesters, DXers and lesser lights, Dec 27, 1500Z to Dec 28, 1500Z defines the time course of this year's running of The Stew Perry Top Band DX Challenge sponsored by The Boring Amateur Radio Club. Operate 14 hours out of this time period to maximize your exposure while staying within the rules. Read, understand and appreciate the rules so that you can see the uniqueness of this contest which may be a template for other contests on lesser bands. The rules which make this a very unique and fun CW contest are at: http://www.kkn.net/stew/ Plaques are sponsored by radio operator heros who devine a category and feel strongly enough to send in $60 by check or $63 by PayPal to The Club to recognize radio competitive feats by the assembled. You, yes you, can join this august group below by notifying me at the address way below. The list below constitutes the radio stalwarts who have sponsored plaques so far for this year. There will be more. DonorCategory KL7RA Top # of QSOs North Pole Contest We are cogitating TF4M Top Score 160M mobile (must actually be able to move) N0TT Top Score < 21 years old > 200 QSOs TF4M Longest Distance QSO- 2 plaques AA6VB Top Score,base loaded Vert <60' tall AA6VB Top Score big city >50K, little pistol <100W KH6LCVK-ZL Challenge: Top Score VK-ZL N5IA Most Grids worked N5IA Highest score daylight operation only K7FL Top Score 100% Search/Pounce NA0YTop Score USA K6NDK6SE Memorial-Top Score World K1EPTop Score by First time Entrant K2POTop Score,S/O,Low Power, Zone 3 TF3KX Aurora Borealis Award- Top Score N of 60 deg N geomagnetic latitude K7CATop Score China K7CATop Score Southern Hemisphere W2GD Team Top # NA+SA Qs by EU Station KR2QGolden Log- Top # of Qs with no busts W7RH Top Score Low Power Asia VK6VZ VK6HD Memorial- Top Score by N hemisphere station working S hemisphere stations. Winner gets Flying Doctors of VK baseball cap. Dr. Beldar-L1AR Top score utilizing temporary antenna. (All parts of temporary antenna including radials must be installed after Dec. 14, 2014. This antenna must be the only antenna for TopBand at the station, and may be left up, because as we all know, "temporary" means "until I die".) Go back and read the list again as there are several plaque possibilities for you to aspire to for this year. Plus, there will undoubtedly be more classifications appearing before the starting bell, as people lose the December fog, regain their senses and sponsor a plaque. The Boring Amateur Radio Club appreciates greatly the fine support that the 160M community has shown it. Combining grid squares with a chance to get away from all the Holiday business for a Top Band RF fest is a winning combination. String up a wire, instead of your complaining neighbor, and join us this year for The Stew Perry Top Band DX Extravaganza! 73 and I remain, Lew w7ew The Boring Amateur Radio Club Scribe and Wire Polisher w...@arrl.net _ Topband Reflector Archives - http://www.contesting.com/_topband
