Re: Topband: The WD8DSB mini-flag antenna
> On 24 Feb 2021, at 02:18, David Raymond wrote: > > anyone here any suggestions for a reasonably good portable receiver with an > external antenna jack (might be hard to find?) that will cover the 160m band > . . .and maybe up to 30 MHz? Hi Dave, How about an SDR (e.g. RSP1A, Funcube dongle or even RTL dongle) and a small laptop or tablet? That way you’d get spectrum and waterfall as well as audio. And you can record everything for analysis / future reference should the interference return. There’s probably an app out there to connect a dongle to your cellphone, but I’ve not investigated that. 73 Chris, G3SVL p.s. can I add my thanks to Don too for the loop design. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: The WD8DSB mini-flag antenna
Hi George, Thanks for mentioning that antenna system thermal noise eventually establishes the limiting factor where additional preamp gain will not provide any additional improvement in performance. Earlier today I was looking for a previous discussion by Tom (W8JI) that explained this very well and I believe he provided some examples but I have not yet located it (but still looking). 73, Don (wd8dsb) On Tue, Feb 23, 2021 at 8:20 PM GEORGE WALLNER wrote: > The smaller the flag the lower its gain and its signal output. The limit > of > usefulness is reached when a weak signal is below the thermal (Johnson) > noise of the system (~ loading resistor). Below this point a pre-amp will > no > longer help. That limits the usefulness of small flags for weak signals, > regardless of RDF. > > 73, > George > AA7JV/C6AGU > > > On Tue, 23 Feb 2021 18:37:03 -0500 > John Kaufmann via Topband wrote: > > As a follow-up to my original post, here are a few additional comments. > > > > Don, you mention that you designed the mini-flag for a deep null off the > > back at low elevation angles, which is entirely understandable. As I > said > > in my earlier post, the null is very pronounced in the AM BCB on local > > groundwave signals. However, I also see pretty significant nulls on > > higher-angle signals, too. Just a short time ago, I was listening to > W1AW > > on the low end of 160. They are located only ~100 miles from me. Their > > signal has to be arriving at a pretty high angle, but the null is still > > quite pronounced. > > > > My homebrew preamp, that I mentioned in my post, uses a cascade of UTO > 511 > > and UTO 533 mini-amplifier modules. I used this preamp, not necessarily > > because it's optimal, but because I already happened to have it on hand. > > The gain of the 511 is given as 16 dB typical while the 533 is 17 dB, > which > > should yield a net gain of ~33 dB for the cascade of the two. The noise > > figure on the 511 that serves as the input amplifier is specified as 2.3 > dB, > > but its spec sheet gives an operational frequency range of 5-500 MHz, so > I > > can't be sure the noise figure (or the gain) holds up at lower > frequencies. > > Nonetheless I can hear the ambient noise in my receiver increase on 160m > > when I connect the mini-flag to the preamp, which suggests the noise > figure > > for this preamp is at least adequate at my location. I use a Yaesu > FT-817ND > > "backpack" radio as a portable radio with this antenna. > > > > In EZNEC I calculate the RDF of this mini-flag as 7.4 dB on 160m at a 20 > > degree elevation angle. That's essentially the same as the K9AY loop or > > other similar pennant/flag antennas. For use as a receiving antenna, the > > important thing is the noise figure of the preamp. The DX Engineering > Web > > site does not give the noise figure of their preamp. > > Don, perhaps you know? > > > > The other thing that might degrade the antenna is common-mode signal > pickup, > > which can be a problem for very low gain antennas where you are working > with > > very small signals. However, based on what I observe in terms of antenna > > pattern for this mini-flag, I can't say that I see any pattern effects > that > > might be attributable to common mode degradation. Don, maybe you can > > comment here as well on this aspect of the antenna. > > > > As I also mentioned in my earlier post, the dimensions of the DXE > > implementation are somewhat smaller than what's given in the QST article. > >For me, that works out well because the width of the DXE mini-flag just > > manages to fit inside the trunk of my mid-size sedan. A wider flag would > > not fit. > > > > 73, John W1FV > > > > -Original Message- > >From: Topband > > [mailto:topband-bounces+john.kaufmann=verizon@contesting.com] On > Behalf > > Of Don Kirk > > Sent: Tuesday, February 23, 2021 5:22 PM > > To: wb6r...@mac.com > > Cc: Top Band List List > > Subject: Re: Topband: The WD8DSB mini-flag antenna > > > > HI Steve, > > > > Thanks for the nice implementation comment. > > > > The portable flag front to back ratio is highly related to the elevation > > angle and frequency of operation (just like any terminated loop), and > > therefore I did not want to overstate the front to back ratio in my > > portable flag article. I designed the portable flag for direction > finding > > local RFI (ground wave based signals) and therefore made sure I selected > an > > appropriate termination resistor to provide a very deep null at low > > elevation angles on 160, 80 and 40 meters where I often deal with RFI > (the > > portable flag has a very high front to back ratio at low elevation > angles), > > and because of this it also has exceptional front to back ratio at low > > elevation angles down in the AM Broadcast Band. Very small flags have > just > > as good front to back ratio and RDF as a full size flag as long as the > > appropriate termination resistor is used. The problem is when the flag
Re: Topband: ARRL CW Contest (and TB Contests generally)
Kudos to our friends "down under" that hang in there and remain QRV on the low bands and fight horrible QRN during their summer months for the benefit of the rest of us "up here." Luke, VK3HJ remains consistently active during our winter months in spite of all the challenges. Thanks Luke! 73. . . Dave, W0FLS On 2/23/2021 5:56 PM, List Mail wrote: I usually have a listen when there’s a Top Band Contest on, but rarely participate, and don’t compete. Conditions are usually poor, with storm static to contend with, as most contests are over our summer. The DX is usually occupied with working NA/EU/JA where there are the numbers, obviously, with little attention being paid to Oceania. Of course, there are so few OC stations on Top Band, that it is hardly worthwhile for the Contesters to spend the time and resources looking for one or two country multipliers. Conditions to NA from VK have been exceptionally poor this year so far, with only a couple of evenings where there has been any sort of opening. Hopefully, there is still some EU propagation next month, when I should have the Quarter wave vertical operational. 73, Luke VK3HJ Sent from Mail for Windows 10 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: The WD8DSB mini-flag antenna
Don. . .thank you for the very nice loop article in QST. And, thank you for your generosity of not taking compensation to help make it affordable. The loop antenna would be a very useful tool to have in the arsenal for DFing interference sources of all kinds which continue to proliferate (even out in the country where I live). I am currently experiencing an interference problem on 160m that is about 10-15 KHz broad with a couple of modest peaks. It often parks in the 1825-1835 KHz window on 160m. The frequency range it occupies wanders some and varies inversely with the outside temperature. I have DFd it fairly close with the HI-Z 8 circle array and know the direction of the source but need something portable to home in on it. Do you or anyone here any suggestions for a reasonably good portable receiver with an external antenna jack (might be hard to find?) that will cover the 160m band . . .and maybe up to 30 MHz? Thanks and 73. . . Dave, W0FLS On 2/23/2021 5:37 PM, John Kaufmann via Topband wrote: As a follow-up to my original post, here are a few additional comments. Don, you mention that you designed the mini-flag for a deep null off the back at low elevation angles, which is entirely understandable. As I said in my earlier post, the null is very pronounced in the AM BCB on local groundwave signals. However, I also see pretty significant nulls on higher-angle signals, too. Just a short time ago, I was listening to W1AW on the low end of 160. They are located only ~100 miles from me. Their signal has to be arriving at a pretty high angle, but the null is still quite pronounced. My homebrew preamp, that I mentioned in my post, uses a cascade of UTO 511 and UTO 533 mini-amplifier modules. I used this preamp, not necessarily because it's optimal, but because I already happened to have it on hand. The gain of the 511 is given as 16 dB typical while the 533 is 17 dB, which should yield a net gain of ~33 dB for the cascade of the two. The noise figure on the 511 that serves as the input amplifier is specified as 2.3 dB, but its spec sheet gives an operational frequency range of 5-500 MHz, so I can't be sure the noise figure (or the gain) holds up at lower frequencies. Nonetheless I can hear the ambient noise in my receiver increase on 160m when I connect the mini-flag to the preamp, which suggests the noise figure for this preamp is at least adequate at my location. I use a Yaesu FT-817ND "backpack" radio as a portable radio with this antenna. In EZNEC I calculate the RDF of this mini-flag as 7.4 dB on 160m at a 20 degree elevation angle. That's essentially the same as the K9AY loop or other similar pennant/flag antennas. For use as a receiving antenna, the important thing is the noise figure of the preamp. The DX Engineering Web site does not give the noise figure of their preamp. Don, perhaps you know? The other thing that might degrade the antenna is common-mode signal pickup, which can be a problem for very low gain antennas where you are working with very small signals. However, based on what I observe in terms of antenna pattern for this mini-flag, I can't say that I see any pattern effects that might be attributable to common mode degradation. Don, maybe you can comment here as well on this aspect of the antenna. As I also mentioned in my earlier post, the dimensions of the DXE implementation are somewhat smaller than what's given in the QST article. For me, that works out well because the width of the DXE mini-flag just manages to fit inside the trunk of my mid-size sedan. A wider flag would not fit. 73, John W1FV -Original Message- From: Topband [mailto:topband-bounces+john.kaufmann=verizon@contesting.com] On Behalf Of Don Kirk Sent: Tuesday, February 23, 2021 5:22 PM To: wb6r...@mac.com Cc: Top Band List List Subject: Re: Topband: The WD8DSB mini-flag antenna HI Steve, Thanks for the nice implementation comment. The portable flag front to back ratio is highly related to the elevation angle and frequency of operation (just like any terminated loop), and therefore I did not want to overstate the front to back ratio in my portable flag article. I designed the portable flag for direction finding local RFI (ground wave based signals) and therefore made sure I selected an appropriate termination resistor to provide a very deep null at low elevation angles on 160, 80 and 40 meters where I often deal with RFI (the portable flag has a very high front to back ratio at low elevation angles), and because of this it also has exceptional front to back ratio at low elevation angles down in the AM Broadcast Band. Very small flags have just as good front to back ratio and RDF as a full size flag as long as the appropriate termination resistor is used. The problem is when the flag becomes too large for the frequency of operation which causes the directional properties to degrade. You can see some front to back ratio vs. elevation plots for my portable
Re: Topband: ARRL CW Contest
Henk hit the nail squarely on the head - 100%. I'll add that even a lot of the top scorers only had 100-300Q's on 160m for an entire weekends work. The easier Q's (rate) are on other bands. ".Lot of people who take part in contest do that because they like to contest, not to make regular qso's. In most contests the purpose is to work as much stations and multipliers. Working as much stations works best on the higher bands. Only reason to come on 160 is to work multipliers, and maybe work some strong stations. 73 Henk PA5KT ." Mike VE9AA Mike, Coreen & Corey Keswick Ridge, NB _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: The WD8DSB mini-flag antenna
The smaller the flag the lower its gain and its signal output. The limit of usefulness is reached when a weak signal is below the thermal (Johnson) noise of the system (~ loading resistor). Below this point a pre-amp will no longer help. That limits the usefulness of small flags for weak signals, regardless of RDF. 73, George AA7JV/C6AGU On Tue, 23 Feb 2021 18:37:03 -0500 John Kaufmann via Topband wrote: As a follow-up to my original post, here are a few additional comments. Don, you mention that you designed the mini-flag for a deep null off the back at low elevation angles, which is entirely understandable. As I said in my earlier post, the null is very pronounced in the AM BCB on local groundwave signals. However, I also see pretty significant nulls on higher-angle signals, too. Just a short time ago, I was listening to W1AW on the low end of 160. They are located only ~100 miles from me. Their signal has to be arriving at a pretty high angle, but the null is still quite pronounced. My homebrew preamp, that I mentioned in my post, uses a cascade of UTO 511 and UTO 533 mini-amplifier modules. I used this preamp, not necessarily because it's optimal, but because I already happened to have it on hand. The gain of the 511 is given as 16 dB typical while the 533 is 17 dB, which should yield a net gain of ~33 dB for the cascade of the two. The noise figure on the 511 that serves as the input amplifier is specified as 2.3 dB, but its spec sheet gives an operational frequency range of 5-500 MHz, so I can't be sure the noise figure (or the gain) holds up at lower frequencies. Nonetheless I can hear the ambient noise in my receiver increase on 160m when I connect the mini-flag to the preamp, which suggests the noise figure for this preamp is at least adequate at my location. I use a Yaesu FT-817ND "backpack" radio as a portable radio with this antenna. In EZNEC I calculate the RDF of this mini-flag as 7.4 dB on 160m at a 20 degree elevation angle. That's essentially the same as the K9AY loop or other similar pennant/flag antennas. For use as a receiving antenna, the important thing is the noise figure of the preamp. The DX Engineering Web site does not give the noise figure of their preamp. Don, perhaps you know? The other thing that might degrade the antenna is common-mode signal pickup, which can be a problem for very low gain antennas where you are working with very small signals. However, based on what I observe in terms of antenna pattern for this mini-flag, I can't say that I see any pattern effects that might be attributable to common mode degradation. Don, maybe you can comment here as well on this aspect of the antenna. As I also mentioned in my earlier post, the dimensions of the DXE implementation are somewhat smaller than what's given in the QST article. For me, that works out well because the width of the DXE mini-flag just manages to fit inside the trunk of my mid-size sedan. A wider flag would not fit. 73, John W1FV -Original Message- From: Topband [mailto:topband-bounces+john.kaufmann=verizon@contesting.com] On Behalf Of Don Kirk Sent: Tuesday, February 23, 2021 5:22 PM To: wb6r...@mac.com Cc: Top Band List List Subject: Re: Topband: The WD8DSB mini-flag antenna HI Steve, Thanks for the nice implementation comment. The portable flag front to back ratio is highly related to the elevation angle and frequency of operation (just like any terminated loop), and therefore I did not want to overstate the front to back ratio in my portable flag article. I designed the portable flag for direction finding local RFI (ground wave based signals) and therefore made sure I selected an appropriate termination resistor to provide a very deep null at low elevation angles on 160, 80 and 40 meters where I often deal with RFI (the portable flag has a very high front to back ratio at low elevation angles), and because of this it also has exceptional front to back ratio at low elevation angles down in the AM Broadcast Band. Very small flags have just as good front to back ratio and RDF as a full size flag as long as the appropriate termination resistor is used. The problem is when the flag becomes too large for the frequency of operation which causes the directional properties to degrade. You can see some front to back ratio vs. elevation plots for my portable flag on my simple portable flag website and here is the URL to that site: https://sites.google.com/site/portableflagantenna/home Problem with very small flags is that the noise figure of the preamp becomes a critical parameter, and because of this I don't recommend attenuators be placed before the preamp as this causes degradation in the signal to noise ratio. I stumbled upon this issue when doing field tests on one of the DX Engineering prototype preamps, and had them change the design so the attenuators now come after the actual amplifier stage which solved the problem. Everything I said above about the perf
Re: Topband: ARRL CW Contest (and TB Contests generally)
I usually have a listen when there’s a Top Band Contest on, but rarely participate, and don’t compete. Conditions are usually poor, with storm static to contend with, as most contests are over our summer. The DX is usually occupied with working NA/EU/JA where there are the numbers, obviously, with little attention being paid to Oceania. Of course, there are so few OC stations on Top Band, that it is hardly worthwhile for the Contesters to spend the time and resources looking for one or two country multipliers. Conditions to NA from VK have been exceptionally poor this year so far, with only a couple of evenings where there has been any sort of opening. Hopefully, there is still some EU propagation next month, when I should have the Quarter wave vertical operational. 73, Luke VK3HJ Sent from Mail for Windows 10 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: The WD8DSB mini-flag antenna
As a follow-up to my original post, here are a few additional comments. Don, you mention that you designed the mini-flag for a deep null off the back at low elevation angles, which is entirely understandable. As I said in my earlier post, the null is very pronounced in the AM BCB on local groundwave signals. However, I also see pretty significant nulls on higher-angle signals, too. Just a short time ago, I was listening to W1AW on the low end of 160. They are located only ~100 miles from me. Their signal has to be arriving at a pretty high angle, but the null is still quite pronounced. My homebrew preamp, that I mentioned in my post, uses a cascade of UTO 511 and UTO 533 mini-amplifier modules. I used this preamp, not necessarily because it's optimal, but because I already happened to have it on hand. The gain of the 511 is given as 16 dB typical while the 533 is 17 dB, which should yield a net gain of ~33 dB for the cascade of the two. The noise figure on the 511 that serves as the input amplifier is specified as 2.3 dB, but its spec sheet gives an operational frequency range of 5-500 MHz, so I can't be sure the noise figure (or the gain) holds up at lower frequencies. Nonetheless I can hear the ambient noise in my receiver increase on 160m when I connect the mini-flag to the preamp, which suggests the noise figure for this preamp is at least adequate at my location. I use a Yaesu FT-817ND "backpack" radio as a portable radio with this antenna. In EZNEC I calculate the RDF of this mini-flag as 7.4 dB on 160m at a 20 degree elevation angle. That's essentially the same as the K9AY loop or other similar pennant/flag antennas. For use as a receiving antenna, the important thing is the noise figure of the preamp. The DX Engineering Web site does not give the noise figure of their preamp. Don, perhaps you know? The other thing that might degrade the antenna is common-mode signal pickup, which can be a problem for very low gain antennas where you are working with very small signals. However, based on what I observe in terms of antenna pattern for this mini-flag, I can't say that I see any pattern effects that might be attributable to common mode degradation. Don, maybe you can comment here as well on this aspect of the antenna. As I also mentioned in my earlier post, the dimensions of the DXE implementation are somewhat smaller than what's given in the QST article. For me, that works out well because the width of the DXE mini-flag just manages to fit inside the trunk of my mid-size sedan. A wider flag would not fit. 73, John W1FV -Original Message- From: Topband [mailto:topband-bounces+john.kaufmann=verizon@contesting.com] On Behalf Of Don Kirk Sent: Tuesday, February 23, 2021 5:22 PM To: wb6r...@mac.com Cc: Top Band List List Subject: Re: Topband: The WD8DSB mini-flag antenna HI Steve, Thanks for the nice implementation comment. The portable flag front to back ratio is highly related to the elevation angle and frequency of operation (just like any terminated loop), and therefore I did not want to overstate the front to back ratio in my portable flag article. I designed the portable flag for direction finding local RFI (ground wave based signals) and therefore made sure I selected an appropriate termination resistor to provide a very deep null at low elevation angles on 160, 80 and 40 meters where I often deal with RFI (the portable flag has a very high front to back ratio at low elevation angles), and because of this it also has exceptional front to back ratio at low elevation angles down in the AM Broadcast Band. Very small flags have just as good front to back ratio and RDF as a full size flag as long as the appropriate termination resistor is used. The problem is when the flag becomes too large for the frequency of operation which causes the directional properties to degrade. You can see some front to back ratio vs. elevation plots for my portable flag on my simple portable flag website and here is the URL to that site: https://sites.google.com/site/portableflagantenna/home Problem with very small flags is that the noise figure of the preamp becomes a critical parameter, and because of this I don't recommend attenuators be placed before the preamp as this causes degradation in the signal to noise ratio. I stumbled upon this issue when doing field tests on one of the DX Engineering prototype preamps, and had them change the design so the attenuators now come after the actual amplifier stage which solved the problem. Everything I said above about the performance of very small terminated loops assumes no interaction with surrounding objects, and ignores issues related with feedlines since the feedline is very short on the portable flag. P.S. I make no money from DX Engineering as I agreed to not be paid in order to keep the price of the portable flag as low as possible. 73, Don (wd8dsb) _ Searchable Archives: http://www.contesting.com/_topband - Topb
Re: Topband: The WD8DSB mini-flag antenna
HI Steve, Thanks for the nice implementation comment. The portable flag front to back ratio is highly related to the elevation angle and frequency of operation (just like any terminated loop), and therefore I did not want to overstate the front to back ratio in my portable flag article. I designed the portable flag for direction finding local RFI (ground wave based signals) and therefore made sure I selected an appropriate termination resistor to provide a very deep null at low elevation angles on 160, 80 and 40 meters where I often deal with RFI (the portable flag has a very high front to back ratio at low elevation angles), and because of this it also has exceptional front to back ratio at low elevation angles down in the AM Broadcast Band. Very small flags have just as good front to back ratio and RDF as a full size flag as long as the appropriate termination resistor is used. The problem is when the flag becomes too large for the frequency of operation which causes the directional properties to degrade. You can see some front to back ratio vs. elevation plots for my portable flag on my simple portable flag website and here is the URL to that site: https://sites.google.com/site/portableflagantenna/home Problem with very small flags is that the noise figure of the preamp becomes a critical parameter, and because of this I don't recommend attenuators be placed before the preamp as this causes degradation in the signal to noise ratio. I stumbled upon this issue when doing field tests on one of the DX Engineering prototype preamps, and had them change the design so the attenuators now come after the actual amplifier stage which solved the problem. Everything I said above about the performance of very small terminated loops assumes no interaction with surrounding objects, and ignores issues related with feedlines since the feedline is very short on the portable flag. P.S. I make no money from DX Engineering as I agreed to not be paid in order to keep the price of the portable flag as low as possible. 73, Don (wd8dsb) _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: The WD8DSB mini-flag antenna
For finding 160 meter noise sources, I use a C-Crane or Sangean pocket AM band radio tuned to 1710 kHz. It also has a very sharp null due to the ferrite loop stick antenna built in. The QST antenna does have the advantage of being unidirectional, but I can often triangulate with the pocket radio by walking around and getting two different null directions. Rick N6RK On 2/23/2021 10:25 AM, John Kaufmann via Topband wrote: Some of you may have seen the article by WD8DSB in the latest issue of QST. I believe WD8DSB is on this reflector. His article describes a mini-flag antenna that can be used for direction-finding. The neat thing about this antenna, besides its compact size, is that it is unidirectional and is very broadband. It works from the AM BCB through 10m. It produces a sharp null off the back which allows you to determine signal direction without the direction ambiguity you get with a conventional unterminated loop. DX Engineering is producing this antenna as a kit, along with a companion preamp. (Disclaimer: I have no affiliation or commercial interest in DX Engineering). See: https://www.dxengineering.com/parts/dxe-noiseloop. I just bought the flag kit last week and finished assembling it this past weekend. I see today that the kit is now back-ordered until April so it was good that I ordered it as soon as I saw the QST article. It took me about 3 hours to assemble the mini-flag even though the DXE Web site says it can be done in 1-2 hours. There is a bit of fussy mechanical assembly involved in getting the symmetry and dimensions just right, although it's not hard work. The flag is 42 inches wide and 21 inches tall. The DXE version of the antenna has slightly smaller dimensions than those given in the QST article, which results in a small reduction in gain, which doesn't really matter, but the pattern is the same. I did some testing of the mini-flag in the AM BCB. The gain is very low--about -65 dBi on 160m--so it needs a good preamp. I used a homebrew preamp made up of a couple of MMIC's that produce about 35 dB of gain. The DXE preamp for this antenna won't be available until April. On the higher frequencies, less preamp gain is needed because the gain of the mini-flag increases with frequency. My initial tests indicate this antenna clearly works. By rotating the flag for the deepest null, I could nail the heading an AM BCB station to a few degrees. This antenna could also be used as directional receiving antenna on its own. Although it is not hugely directive, it can be rotated easily to peak or null signals or noise, and it is better than a conventional unterminated loop. It has essentially the same RDF as other larger flag or pennant antennas but is obviously far more compact. This is a nice contribution by WD8DSB. Now I have to go off with the mini-flag and chase some local noise sources that have been plaguing me this winter on the low bands. 73, John W1FV _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: The WD8DSB mini-flag antenna
Yes very nice article and design by Don. Flags/loops do not exhibit gain but rather directivity. The larger the loop the greater the capture area and the less of a need for a preamp. I routinely use my full size flag without any preamp external to the rig. A correctly designed and built full size flag will exhibit front/back of 25-30 db. If smaller loops (and I've tried many) have "essentially the same RDF as other larger flag or pennant antennas" I could have saved myself a lot of work by never having put up a full size flag. Size matters. For the purpose of direction finding of relatively close noise sources, Don's implementation looks excellent. 73 - Steve WB6RSE > On Feb 23, 2021, at 10:25 AM, John Kaufmann via Topband > wrote: > > This antenna could also be used as directional receiving antenna on its own. > Although it is not hugely directive, it can be rotated easily to peak or > null signals or noise, and it is better than a conventional unterminated > loop. It has essentially the same RDF as other larger flag or pennant > antennas but is obviously far more compact. > > > > This is a nice contribution by WD8DSB. Now I have to go off with the > mini-flag and chase some local noise sources that have been plaguing me this > winter on the low bands. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: The WD8DSB mini-flag antenna
Some of you may have seen the article by WD8DSB in the latest issue of QST. I believe WD8DSB is on this reflector. His article describes a mini-flag antenna that can be used for direction-finding. The neat thing about this antenna, besides its compact size, is that it is unidirectional and is very broadband. It works from the AM BCB through 10m. It produces a sharp null off the back which allows you to determine signal direction without the direction ambiguity you get with a conventional unterminated loop. DX Engineering is producing this antenna as a kit, along with a companion preamp. (Disclaimer: I have no affiliation or commercial interest in DX Engineering). See: https://www.dxengineering.com/parts/dxe-noiseloop. I just bought the flag kit last week and finished assembling it this past weekend. I see today that the kit is now back-ordered until April so it was good that I ordered it as soon as I saw the QST article. It took me about 3 hours to assemble the mini-flag even though the DXE Web site says it can be done in 1-2 hours. There is a bit of fussy mechanical assembly involved in getting the symmetry and dimensions just right, although it's not hard work. The flag is 42 inches wide and 21 inches tall. The DXE version of the antenna has slightly smaller dimensions than those given in the QST article, which results in a small reduction in gain, which doesn't really matter, but the pattern is the same. I did some testing of the mini-flag in the AM BCB. The gain is very low--about -65 dBi on 160m--so it needs a good preamp. I used a homebrew preamp made up of a couple of MMIC's that produce about 35 dB of gain. The DXE preamp for this antenna won't be available until April. On the higher frequencies, less preamp gain is needed because the gain of the mini-flag increases with frequency. My initial tests indicate this antenna clearly works. By rotating the flag for the deepest null, I could nail the heading an AM BCB station to a few degrees. This antenna could also be used as directional receiving antenna on its own. Although it is not hugely directive, it can be rotated easily to peak or null signals or noise, and it is better than a conventional unterminated loop. It has essentially the same RDF as other larger flag or pennant antennas but is obviously far more compact. This is a nice contribution by WD8DSB. Now I have to go off with the mini-flag and chase some local noise sources that have been plaguing me this winter on the low bands. 73, John W1FV _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Topband Digest, Vol 218, Issue 16
Somebody need use his rx antenna not the websdr, that is strange Andy DL8LAS with good rx system not have good condition during contest, every time new miracles on 160m, still wait any good video or audio recorder of this wonderfull condition. Il mar 23 feb 2021, 18:01 ha scritto: > Send Topband mailing list submissions to > topband@contesting.com > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.contesting.com/mailman/listinfo/topband > or, via email, send a message with subject or body 'help' to > topband-requ...@contesting.com > > You can reach the person managing the list at > topband-ow...@contesting.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Topband digest..." > > > Today's Topics: > >1. Re: Topband Digest, Vol 218, Issue 15 (Theo Bemelmans) >2. ARRL WW - 160 cndx - mixed bag (w3...@roadrunner.com) >3. Re: ARRL CW Contest (Richard (Rick) Karlquist) >4. Re: ARRL CW Contest (Henk Remijn PA5KT) >5. Off air (List Mail) >6. Re: Off air (List Mail) > > > -- > > Message: 1 > Date: Mon, 22 Feb 2021 18:22:02 +0100 > From: "Theo Bemelmans" > To: > Subject: Re: Topband: Topband Digest, Vol 218, Issue 15 > Message-ID: <01d7093f$3bfaa2b0$b3efe810$@pandora.be> > Content-Type: text/plain; charset="us-ascii" > > Hi all, > > Long time ago i did post something on here. I agree with Roger about > activity outside the contests ! > I was active for just 5 hours spread over Saterday and Sunday morning and > did manage to work 232 stations US/VE. 38 states worked. > Online contest server gives me a nice 6th place worldwide as a SOSB160 > HP,which pleases me. > Glad to compete from a normal city lot with some of the biggest contest > stations in Europe. > My antenna is a new ,this winter i build me a 2 el sloper array and it is > playing very well. > The most far west i worked was OR (W7ZI) and some midwest like N0RIM in MO, > also LA,OK etc. > > For me conditions were no bad at all, but i can always better hi. > > OT4A > Theo > > -Oorspronkelijk bericht- > Van: Topband > Namens topband-requ...@contesting.com > Verzonden: maandag 22 februari 2021 18:01 > Aan: topband@contesting.com > Onderwerp: Topband Digest, Vol 218, Issue 15 > > Send Topband mailing list submissions to > topband@contesting.com > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.contesting.com/mailman/listinfo/topband > or, via email, send a message with subject or body 'help' to > topband-requ...@contesting.com > > You can reach the person managing the list at > topband-ow...@contesting.com > > When replying, please edit your Subject line so it is more specific than > "Re: Contents of Topband digest..." > > > Today's Topics: > >1. ARRL CW Contest (Roger Kennedy) >2. Re: ARRL CW Contest (Tim Shoppa) >3. Re: ARRL CW Contest (David Raymond) >4. Re: ARRL CW Contest (w...@w5zn.org) >5. Re: ARRL CW Contest (Artek Manuals) >6. ARRL CW Contest (Roger Kennedy) >7. Re: ARRL CW Contest (Ilmo Anttil) >8. Re: ARRL CW Contest (Don Kirk) >9. Re: ARRL CW Contest (wa8...@wa8wzg.net) > > > -- > > Message: 1 > Date: Mon, 22 Feb 2021 11:49:25 - > From: "Roger Kennedy" > To: > Subject: Topband: ARRL CW Contest > Message-ID: <7330E990D6054DE7AD5681F06B4A2F06@Packard> > Content-Type: text/plain; charset="us-ascii" > > > Well conditions to NA from EU were pretty good over the weekend. > > I came on 160m for a couple of hours on Friday Night, and again on Saturday > night . . . > > Managed to work a total of 132 NA stations, which I was really pleased > with. > > That included lots of people that I had never worked before . . . but what > saddens me, is why these people don't come on Top Band when there ISN'T a > Contest ! > > Roger G3YRO > > > > > -- > > Message: 2 > Date: Mon, 22 Feb 2021 08:56:16 -0500 > From: Tim Shoppa > To: Roger Kennedy > Cc: topBand List > Subject: Re: Topband: ARRL CW Contest > Message-ID: > < > caj_qrvyju96bevz401sabls+8thijopwa3vzbfaztc8fbrj...@mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Yes! Signals from EU were huge on 160 for many hours both nights. I had to > peer at my radio dial a few times just to be sure I wasn't accidentally on > 80 or something. 80 was great too. > > How far west in US/Canada did you work, Roger? > > Tim N3QE > > On Mon, Feb 22, 2021 at 6:49 AM Roger Kennedy > > wrote: > > > > > Well conditions to NA from EU were pretty good over the weekend. > > > > I came on 160m for a couple of hours on Friday Night, and again on > > Saturday night . . . > > > > Managed to work a total of 132 NA stations, which I was really pleased > > with. > > > > That included lots of people tha
Topband: ARRL 160m DR5X
Hey,I worked in the first night 180 and the second night 109 stations from NA.The most signals were weak and not easy tocopy, the best hour was from 3 to 4 UTC with 60 QSOs.Complete now 289 QSOs with 39 states.Nothing heard from the westcoast.At the end I have 100 QSOs less than last year 2020.But I had fun and hope the condx will be better soon.73 Andy DL8LAS / DR5X _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Off air
Mail from the reflector has caught up here. There was an issue with my mail server. The Top loaded vertical was removed on the weekend, as the Quarter wave vertical I am building next to it detuned it. There are two more mast sections to bolt up with about 5 m of Al mast to go above that. At a height of 28.6 m, it is resonant at 2245 kHz, so according to my calculations, it should be resonant on 1825 kHz at around 35 m without top loading. Completion will have to wait until next week, as this weekend I will be spending four days cycling in the Victorian Alps, so I’m saving my climbing legs for that! 73, de Luke VK3HJ. Sent from Mail for Windows 10 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Off air
I took my top loaded vertical tx antenna down over the weekend, so am off air for a while on Top. I’ve also not seen any mail come in on the List since 18th Feb. 73, Luke VK3HJ Sent from Mail for Windows 10 _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
