Topband: Elimination of Treadmill RFI on 160 meters
For many years my wife's treadmill caused strong interference on 160 meters when it was in use, and yesterday I was able to completely eliminate the RFI using a combination of two different filters (a commercial line filter that provides both common mode and differential mode filtering, and 14 turns of the power cord on a 2.4 OD Fair-Rite #31 mix toroid core based on the K9YC hams guide to RFI document). I created a simple website that documents my tests and the filters used, and for those interested the website URL is http://sites.google.com/site/treadmillrfi/ The website contains a link to a video on youtube where you can actually see the effectiveness of the filters. 73, Don (wd8dsb) _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Looking for 160m narrow beam RX advice - an interesting combination of ideas
An array of loops is two loops for two directions. Hi guys The simple solution that is working very well since 2009 is the HWF. Why not two horizontal loaded loops end-fire. Two identical horizontal loops see the ground wave signal at the same way Va=Vb and because the 180 degree out of phase we have Va-Vb=0 . A loaded loop has a cardioid patter and two in phase , like the horizontal WF , have over 90 dB attenuation on vertical polarized signals at the front lobe and at same time has 11.5 to 1332 dB directivity for horizontal signals The main lobe is near 40 degree and + - 20 degree for 3db, it means deep null from 90 degree plane, not only from the side , also with a 5 to 8 degree difference in phase you can enjoy 20 to 40 F.B. So the HWF can null the noise in all direction coming from ground wave, simple as that. You can turn the HWF and aim to the DX with good directivity like a 3 elements full size beam from 160, 80, 40 and 30m in one single feed line. The HWF needs to be at least 30 Ft. high for 80m and 60 Ft high for good performance on 160m. Even on 40m and 30m the HWF offer the same noiseless performance. I called noiseless because with 90 dB attenuation on ground wave, mainly man made noise, the noise level during the day without propagation noise or sky wave is below the noise floor of the receiver. The challenger is to avoid any common mode noise pickup from the feed line, the feed line is a vertical antenna and it will deteriorate the vertical attenuation if you don't choke it, not that shield is our enemy for that. Quad shield just increase the common mode noise problems. I recorded some signals comparing a good RDF vertical HF, is my main antenna for almost 10 years, I built on in 2006. The results speak for itself, it is a booring 10 minutes video and at the end somebody started a huge intentional QRM on top of the DX, unbelievable bad in all aspects. It is my Drop box https://www.dropbox.com/s/xqrtj86jout29ph/MVI_0075.MP4?dl=0 Another solution not so efficient because does not have directivity, but works very well is the old K6STI loop http://www.angelfire.com/md/k3ky/page45.html Same issue , you need to use unshielded twisted pair to feed the loop, no shield !!! you don't what that on the feed line. 73's N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Radio-communications page from the SWPC
Has everyone allready seen this new (to me) page from the SWPC? - Very cool... http://www.swpc.noaa.gov/communities/radio-communications _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Looking for 160m narrow beam RX advice - an interesting com
G/E Guys, All subdivision Top Banders need an effective, highly directional receive antenna that is minimally affected by local wires and metal, has side and rear nulls to take care of interfering directional noises, may be mounted adjacent to xmit towers and power lines, and rotated in a small space over the roof to give Rotary 800 ft. Beverage performance. Such an antenna has existed since 2002, and will soon be available commercially. Please visit http://nx4d10.wix.com/waller-flag to learn how to work 300+ countries and 40 zones on 160, and score higher in contests on 160 meters from your own lot. This antenna can receive vertically, horizontally, or anywhere in between, matching the incoming weak DX signal tilt angle for stunning reception, while minimizing man made noise and eliminating fading. Happy New Year. 73, Doug / Nx4d _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Announcing the 2015 Dayton TopBand Dinner - 26th Annual Event!
Continuing the great Top Band dinner tradition that George, K8GG and George, W8UVZ started, I am proud to announce the 26th Annual Dayton TopBand dinner. Dinner reservations are now available for 2015! Friday evening May 15, 2015 at the Crowne Plaza in the Presidential Ballroom - downtown Dayton, Ohio. Top Band Social hour is at 6:15 PM and Dinner starts at 7:15 PM. Come and have dinner with the guys you work on 160 meters and enjoy great TopBand discussions. The excellent Top Band program is being assembled. I will update the website soon. Dinner reservations are available on line with credit cards and PayPal. Use the contact us information from the web site if you need to make other arrangements. The 2015 Dayton Top Band Dinner details are here: http://topbanddinner.com Scroll down to make your reservations. Four nights of great Top Band, DX and Contesting hospitality are also at the Crowne Plaza Contest Super Suite. Details are here: http://contestsupersuite.com Slots are filling up fast at Dayton Contest University http://contestuniversity.com If you enjoy making QSOs on the 160 meter band, the 26th Annual Top Band Dinner is for you! Hope to see you at the 2015 Dayton TopBand Dinner 73, Tim K3LR Dayton Top Band Dinner Chairman _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Looking for 160m narrow beam RX advice - an interesting combination of ideas
Hi Guys I uploaded the video on YouTube on this link, DropBox is not working. http://youtu.be/dNBekvzlxgM Hi guys The simple solution that is working very well since 2009 is the HWF. Why not two horizontal loaded loops end-fire. Two identical horizontal loops see the ground wave signal at the same way Va=Vb and because the 180 degree out of phase we have Va-Vb=0 . A loaded loop has a cardioid patter and two in phase , like the horizontal WF , have over 90 dB attenuation on vertical polarized signals at the front lobe and at same time has 11.5 to 1332 dB directivity for horizontal signals The main lobe is near 40 degree and + - 20 degree for 3db, it means deep null from 90 degree plane, not only from the side , also with a 5 to 8 degree difference in phase you can enjoy 20 to 40 F.B. So the HWF can null the noise in all direction coming from ground wave, simple as that. You can turn the HWF and aim to the DX with good directivity like a 3 elements full size beam from 160, 80, 40 and 30m in one single feed line. The HWF needs to be at least 30 Ft. high for 80m and 60 Ft high for good performance on 160m. Even on 40m and 30m the HWF offer the same noiseless performance. I called noiseless because with 90 dB attenuation on ground wave, mainly man made noise, the noise level during the day without propagation noise or sky wave is below the noise floor of the receiver. The challenger is to avoid any common mode noise pickup from the feed line, the feed line is a vertical antenna and it will deteriorate the vertical attenuation if you don't choke it, not that shield is our enemy for that. Quad shield just increase the common mode noise problems. I recorded some signals comparing a good RDF vertical HF, is my main antenna for almost 10 years, I built on in 2006. The results speak for itself, it is a booring 10 minutes video and at the end somebody started a huge intentional QRM on top of the DX, unbelievable bad in all aspects. It is my Drop box https://www.dropbox.com/s/xqrtj86jout29ph/MVI_0075.MP4?dl=0 Another solution not so efficient because does not have directivity, but works very well is the old K6STI loop http://www.angelfire.com/md/k3ky/page45.html Same issue , you need to use unshielded twisted pair to feed the loop, no shield !!! you don't what that on the feed line. 73's N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Radio-communications page from the SWPC
It's good, but www.swpc.noaa.gov/communities/space-weather-enthusiasts is better. That one also has the 5-graph ACE real-time solar wind chart. 73, Mike www.w0btu.com On Thu, Jan 8, 2015 at 8:07 AM, bruce whitney via Topband topband@contesting.com wrote: Has everyone allready seen this new (to me) page from the SWPC? - Very cool... http://www.swpc.noaa.gov/communities/radio-communications _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Looking for 160m narrow beam RX advice - an interesting combination of ideas
On 1/8/2015 5:36 AM, JC wrote: An array of loops is two loops for two directions. Hi guys The simple solution that is working very well since 2009 is the HWF. Why not two horizontal loaded loops end-fire. Two identical horizontal loops see the ground wave signal at the same way Va=Vb and because the 180 degree I have been modeling horizontal loops recently. The idea is to reject vertically polarized ground wave noise. As far as I can tell, a horizontal loop rejects vertically polarized noise from any direction. As opposed to a dipole that receives vertically polarized signals from the ends. You can make the loop just about any size or shape and terminate the side opposite the feed with a resistor of around 1000 ohms to get a cardioid pattern. There is a resonance when the perimeter of the loop is a half wave long, so you need to stay somewhat below this length, which would be something like 260 feet on 160 meters. That's a huge loop. The higher the loop and the bigger the loop, the more signal you get (that is gross signal, not SNR). You need to overcome your preamp noise. As JC says, these loops can be the building blocks of an array. I am going to try to get a horizontal loop aimed at 70 degrees up for the upcoming CQWW contests as a proof of concept. In the recent SP, I tried a horizontal dipole, but it was no better than the transmit vertical. In the past, dipoles have been good receiving antennas. I am thinking it is a matter of what direction the dominant noise is coming from as to whether they work. The loop doesn't have that issue. Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Looking for 160m narrow beam RX advice - an interesting combination of ideas
I am going to try to get a horizontal loop aimed at 70 degrees up Hi Rick It is not recommended to tilt and elevate the loop. There is two reasons it improve the signal to noise ratio, First is the attenuation of the vertical component at the same direction you are receiving the DX signal, Second is the directivity for horizontal signal. Her the first one is the most important to kill local ground noise. I used to tune the HWF for best RDF, but I've seen better results tuning it for max attenuation of the vertical field. Since I did that I rarely use my vertical WF, including for signals coming due north. Horizontal signals get very attenuated near the ground, that's why you should install the loops or the loop as high you can. Different from dipoles the takeoff angle is the same for any height above ground. Long path propagation SSE SSW is the most interesting observation of polarization coming horizontal polarized. Since I install the first HWF back in 2009 I started to copy long path signals from South Asia in a daily base during Fall and Winter. 6 month season. On 160m, the activity is a key factor, like I heard Peter from HS0ZAI the only day he was active on 160m, I cant say the propagation is not open if there is no activity. There have been several reports of long path propagation this year on 160m , on 80 m is it pretty common. The HWF because the difference in polarization , the interaction with TX antenna is 25 to 27 dB reduced. But not the same for low dipoles, elevated radials or any other resonant wire or structure at the same band,, Remember the HWF has the same performance on 160 . 80. 40 and some good usability on 30m, However the gain is different, like 160m -50 dB, 80m -30 dB , 40m -10 dB e almost some gain on 30m, these figures depend on the size of the HWF. This also means the same preamp is not recommended for all bands, it needs to be tuned and what I use is preamp tuned per band with the adequate gain. Just few days ago I measure signal from two local broadcast in South Caroline, Radio Martã aimed for Cuba, on 11.930 MHz signal at the receiver -13dBm (s9+60) and 13.820 MHz, -20 dBm , the preamp can/may handle it but these numbers can overload any receiver if you don't adjust the gain. Also the IM or PIM became a problem , the product of 1890 can be very strong. Regards JC N4IS -Original Message- From: Richard (Rick) Karlquist [mailto:rich...@karlquist.com] Sent: Thursday, January 08, 2015 2:36 PM To: JC; 'topband' Subject: Re: Topband: Looking for 160m narrow beam RX advice - an interesting combination of ideas On 1/8/2015 5:36 AM, JC wrote: An array of loops is two loops for two directions. Hi guys The simple solution that is working very well since 2009 is the HWF. Why not two horizontal loaded loops end-fire. Two identical horizontal loops see the ground wave signal at the same way Va=Vb and because the 180 degree I have been modeling horizontal loops recently. The idea is to reject vertically polarized ground wave noise. As far as I can tell, a horizontal loop rejects vertically polarized noise from any direction. As opposed to a dipole that receives vertically polarized signals from the ends. You can make the loop just about any size or shape and terminate the side opposite the feed with a resistor of around 1000 ohms to get a cardioid pattern. There is a resonance when the perimeter of the loop is a half wave long, so you need to stay somewhat below this length, which would be something like 260 feet on 160 meters. That's a huge loop. The higher the loop and the bigger the loop, the more signal you get (that is gross signal, not SNR). You need to overcome your preamp noise. As JC says, these loops can be the building blocks of an array. I am going to try to get a horizontal loop aimed at 70 degrees up for the upcoming CQWW contests as a proof of concept. In the recent SP, I tried a horizontal dipole, but it was no better than the transmit vertical. In the past, dipoles have been good receiving antennas. I am thinking it is a matter of what direction the dominant noise is coming from as to whether they work. The loop doesn't have that issue. Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Looking for 160m narrow beam RX advice - an interesting combination of ideas
On 1/8/2015 12:12 PM, JC wrote: I am going to try to get a horizontal loop aimed at 70 degrees up Hi Rick It is not recommended to tilt and elevate the loop. There is two reasons it Clarification: 70 degrees refers to the AZIMUTH that the loop will be aimed for. It will still be in a horizontal plane, NOT tilted. Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
