Topband: Receiving
As I do not have space for a decent receiving antenna, what is the consensus of opinion on say txing on 160 and rxing on another band, what would such a Qso count as ? 73 Steve, ZC4Li. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving
The Hi-Z 3 element and 4 element (4 sq) receiving antennas have a comparatively small footprint and provide excellent performance. 73. . .Dave W0FLS - Original Message - From: To: Sent: Tuesday, September 06, 2011 1:22 AM Subject: Topband: Receiving > As I do not have space for a decent receiving > antenna, what is the consensus of opinion on > say txing on 160 and rxing on another band, > what would such a Qso count as ? > > > 73 Steve, ZC4Li. > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving
I greatly enjoy using my HI-Z Three element array and just added computer controlled direction switching and a desktop direction display. I can now change directions with the click of the mouse and also do the same by touching a direction button on the touch screen. 73, Jack W0UCE -Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of David Raymond Sent: Tuesday, September 06, 2011 1:47 PM To: hodg...@cytanet.com.cy; topband@contesting.com Subject: Re: Topband: Receiving The Hi-Z 3 element and 4 element (4 sq) receiving antennas have a comparatively small footprint and provide excellent performance. 73. . .Dave W0FLS - Original Message - From: To: Sent: Tuesday, September 06, 2011 1:22 AM Subject: Topband: Receiving > As I do not have space for a decent receiving > antenna, what is the consensus of opinion on > say txing on 160 and rxing on another band, > what would such a Qso count as ? > > > 73 Steve, ZC4Li. > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Receiving loops
I want to try a new receiving antenna for the summer Stew Perry. Last winter was my first foray onto 160M and I really felt like an alligator. I could work everyone I could hear, with just 100W. I think that means I need a better receive antenna. If you look at my score in the winter Stew Perry I think I did great QSO-number wise, but my average distance was very poor, I'm guessing typical alligator. I have tried pennants and K9AY's over the winter with little success. Compared to my transmitting antenna (A "T" with a poor radial system) most signals were still better, S/N wise, on my transmitting antenna. I feel like I must've been doing something wrong. Still the fact that a few signals came in on the loop with by ear much better S/N, maybe I was on the right track and just didn't try hard enough. I will be trying a small tuned magnetic loop tonight (e.g. the last one at http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) . And maybe a terminated beverage but I'm limited to about 150'... well maybe I could run something longer down the driveway as long as I clean it up before the sun comes up and the neighbors see. I was fairly impressed with small tuned magnetic loops when I was doing some BCB DX'ing several years ago. I wasn't comparing with beverages or anything. Tim N3QE ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Receiving loops
Tim, Your receiving antennas may be picking up re-radiation, of noise and signals, from the transmitting antenna. Try detuning the TX antenna while receiving. (If best receiving on the loop is with the null toward the TX antenna, it is a indication.) 73 Bruce-K1FZ I have tried pennants and K9AY's over the winter with little success. Compared to my transmitting antenna (A "T" with a poor radial system) most signals were still better, S/N wise, on my transmitting antenna. I feel like I must've been doing something wrong. Still the fact that a few signals came in on the loop with by ear much better S/N, maybe I was on the right track and just didn't try hard enough. Tim N3QE ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving +1
Steve, as I have also post stam lot for antennas available I tried various antennas. I have to say most of them does not work! Mainly because of strong coupling between RX and TX antennas on my small lot. After several years I found that as still effective is W2PM Mini Diammond loop or K9FD loop (or similar design) + Half sloper or inverted L antenna with decent radials system both on 160m band. You will not be Topband big gun but You will be on the air and even during good condx and serious antenna on the second side You will be able to work sometime DXs. My 2cents aid if it help, 73 - Petr, OK1RP --- http://topband.blog.cz On Tue, 6 Sep 2011 09:22:36 +0300, hodg...@cytanet.com.cy said: > As I do not have space for a decent receiving > antenna, what is the consensus of opinion on > say txing on 160 and rxing on another band, > what would such a Qso count as ? > > > 73 Steve, ZC4Li. > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Why don't you try a 150' BOG? I know a guy in Maryland who has one only 140' long, and he hears DX on it on 160 that he doesn't on his inverted-L. Probably better than a BOG is a Slinky Beverage. 73, Mike http://www.w0btu.com/Beverage_antennas.html ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Tim: I laid down a Dipole On Ground (DOG antenna) - it ended up at just right at 150' (two 75' sections) as indicated by an MFJ-259 analyzer I used that says it's spot on at 1.2:1! Compared to my 43' vertical, noise levels are down at least 2 S units - something to consider, when space is limited. 72, Jim Rodenkirch K9JWV > From: tsho...@wmata.com > To: topband@contesting.com > Date: Sat, 16 Jun 2012 13:28:38 + > Subject: Topband: Receiving loops > > I want to try a new receiving antenna for the summer Stew Perry. Last winter > was my first foray onto 160M and I really felt like an alligator. I could > work everyone I could hear, with just 100W. I think that means I need a > better receive antenna. If you look at my score in the winter Stew Perry I > think I did great QSO-number wise, but my average distance was very poor, I'm > guessing typical alligator. > > I have tried pennants and K9AY's over the winter with little success. > Compared to my transmitting antenna (A "T" with a poor radial system) most > signals were still better, S/N wise, on my transmitting antenna. I feel like > I must've been doing something wrong. Still the fact that a few signals came > in on the loop with by ear much better S/N, maybe I was on the right track > and just didn't try hard enough. > > I will be trying a small tuned magnetic loop tonight (e.g. the last one at > http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) . > And maybe a terminated beverage but I'm limited to about 150'... well maybe I > could run something longer down the driveway as long as I clean it up before > the sun comes up and the neighbors see. > > I was fairly impressed with small tuned magnetic loops when I was doing some > BCB DX'ing several years ago. I wasn't comparing with beverages or anything. > > Tim N3QE > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
I will second Bruce's comments. Re-radiated noise is almost exactly what you are describing. I started using terminated loops around 2000 and even though everyone said that the transmit antennas needed to be detuned when receiving, I was stubborn and didn't follow the advice immediately. The loops were noisy and lacked directivity. I caved and added a circuit to detune on receive and the loops got quiet and were really quite directive compared to what they had been. As a side note - I had need to install a low 80m dipole last summer temporarily. I did not provide a means to detune it - I never thought about it really as it was completely off my radar. It was not until I tried to use the RX loops on 80 that I realized what I had done (or note done as the case was). Anyway, that dipole came down pretty quickly and the loops began behaving normally again.. Any RX antenna is going to behave similarly - shielded loop, K9AY loop, beverage, it does not matter - if you don't detune the TX antenna or get the RX antenna a long way away from that TX antenna. 73 and good luck, John KB5NJD.. From: Bruce To: topband@contesting.com Sent: Sat, June 16, 2012 11:58:36 AM Subject: Topband: Receiving loops Tim, Your receiving antennas may be picking up re-radiation, of noise and signals, from the transmitting antenna. Try detuning the TX antenna while receiving. (If best receiving on the loop is with the null toward the TX antenna, it is a indication.) 73 Bruce-K1FZ ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Tim -- If the suggestions from others don't entirely do the trick, here's another thing to consider: The outer conductor on your coax might be picking up local noise and/or destroying the pattern of your receiving antenna. I DX the AM broadcast band with whatever antennas I can fit into my suburban backyard. I was getting poor results with a pennant until I put Radio Works T-4 line isolators at both ends of the coax. Suddenly the antenna began to behave as expected. Hope this helps. Art DelibertKB3FJO > From: tsho...@wmata.com > To: topband@contesting.com > Date: Sat, 16 Jun 2012 13:28:38 + > Subject: Topband: Receiving loops > > I want to try a new receiving antenna for the summer Stew Perry. Last winter > was my first foray onto 160M and I really felt like an alligator. I could > work everyone I could hear, with just 100W. I think that means I need a > better receive antenna. If you look at my score in the winter Stew Perry I > think I did great QSO-number wise, but my average distance was very poor, I'm > guessing typical alligator. > > I have tried pennants and K9AY's over the winter with little success. > Compared to my transmitting antenna (A "T" with a poor radial system) most > signals were still better, S/N wise, on my transmitting antenna. I feel like > I must've been doing something wrong. Still the fact that a few signals came > in on the loop with by ear much better S/N, maybe I was on the right track > and just didn't try hard enough. > > I will be trying a small tuned magnetic loop tonight (e.g. the last one at > http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) . > And maybe a terminated beverage but I'm limited to about 150'... well maybe I > could run something longer down the driveway as long as I clean it up before > the sun comes up and the neighbors see. > > I was fairly impressed with small tuned magnetic loops when I was doing some > BCB DX'ing several years ago. I wasn't comparing with beverages or anything. > > Tim N3QE > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
you want to talk alligators try a 7' tall vertical @ 20' as your only TX/RX antenna and a bottom floor apartment, where I might try a 6' loop if I can build it in the next few hours, hi hi gud luck Tim GB & 73 K5OAI Sam Morgan On 6/16/2012 8:28 AM, Shoppa, Tim wrote: > I want to try a new receiving antenna for the summer Stew Perry. Last winter > was my first foray onto 160M and I really felt like an alligator. I could > work everyone I could hear, with just 100W. I think that means I need a > better receive antenna. If you look at my score in the winter Stew Perry I > think I did great QSO-number wise, but my average distance was very poor, I'm > guessing typical alligator. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
oops, did I forget to mention my S-9 24/7 noise floor, my bad -- GB & 73 K5OAI Sam Morgan On 6/16/2012 9:46 AM, Sam Morgan wrote: > you want to talk alligators > try a 7' tall vertical @ 20' as your only TX/RX antenna > and a bottom floor apartment, where I might try a 6' loop > if I can build it in the next few hours, hi hi > gud luck Tim > > GB & 73 > K5OAI > Sam Morgan > > On 6/16/2012 8:28 AM, Shoppa, Tim wrote: >> I want to try a new receiving antenna for the summer Stew Perry. Last winter >> was my first foray onto 160M and I really felt like an alligator. I could >> work everyone I could hear, with just 100W. I think that means I need a >> better receive antenna. If you look at my score in the winter Stew Perry I >> think I did great QSO-number wise, but my average distance was very poor, I'm >> guessing typical alligator. > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Hi Tim I also agree with the previous comments on this thread about detuning the transmit antenna (or any other wires/cables that are resonant on 160M) and isolating the coax feed line from the RX loop. It is also important to identify the direction of the main source of the noise and orientate the loop accordingly so that is being properly nulled. I use a small portable tuned loop to identify the direction of the noise.. Of course, if the noise is coming from the same direction as the DX then you are not going to see much (or any ) improvement in the signal-to-noise ratio. Also, if the noise sources are in multiple directions then it will also be difficult to null the noise properly. I have found that small tuned loops (with their bidirectional nulls) are often more effective in such a situation. One of the problems with small tuned loops made from wire is their low sensitivity. Rather than using a pre-amp you can boost the output by making the loop larger (e.g., a circumference of 0.1 wavelength or even larger). The larger loop maintains a directional pattern similar to the smaller one but also exhibits a higher radiation radiation resistance and hence lower losses. Good luck with the experiments and let us know how you get on. 73, Brian VK3MI ZL1AZE > From: tsho...@wmata.com > To: topband@contesting.com > Date: Sat, 16 Jun 2012 13:28:38 + > Subject: Topband: Receiving loops > > I want to try a new receiving antenna for the summer Stew Perry. Last > winter was my first foray onto 160M and I really felt like an alligator. I > could work everyone I could hear, with just 100W. I think that means I > need a better receive antenna. If you look at my score in the winter Stew > Perry I think I did great QSO-number wise, but my average distance was > very poor, I'm guessing typical alligator. > > I have tried pennants and K9AY's over the winter with little success. > Compared to my transmitting antenna (A "T" with a poor radial system) most > signals were still better, S/N wise, on my transmitting antenna. I feel > like I must've been doing something wrong. Still the fact that a few > signals came in on the loop with by ear much better S/N, maybe I was on > the right track and just didn't try hard enough. > > I will be trying a small tuned magnetic loop tonight (e.g. the last one at > http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) > . And maybe a terminated beverage but I'm limited to about 150'... well > maybe I could run something longer down the driveway as long as I clean it > up before the sun comes up and the neighbors see. > > I was fairly impressed with small tuned magnetic loops when I was doing > some BCB DX'ing several years ago. I wasn't comparing with beverages or > anything. > > Tim N3QE > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Sensitivity is not always important. Small loops in general receive less noise and the real exercise is balancing the internal noise floor against the actual signal received. In some cases a loss up to 20 db can be acceptable the numbers are easy enough to run. On 6/16/12 8:17 PM, Brian Miller wrote: > Hi Tim > > I also agree with the previous comments on this thread about detuning the > transmit antenna (or any other wires/cables that are resonant on 160M) and > isolating the coax feed line from the RX loop. > > It is also important to identify the direction of the main source of the > noise and orientate the loop accordingly so that is being properly nulled. I > use a small portable tuned loop to identify the direction of the noise.. > > Of course, if the noise is coming from the same direction as the DX then you > are not going to see much (or any ) improvement in the signal-to-noise > ratio. Also, if the noise sources are in multiple directions then it will > also be difficult to null the noise properly. I have found that small tuned > loops (with their bidirectional nulls) are often more effective in such a > situation. > > One of the problems with small tuned loops made from wire is their low > sensitivity. Rather than using a pre-amp you can boost the output by making > the loop larger (e.g., a circumference of 0.1 wavelength or even larger). > The larger loop maintains a directional pattern similar to the smaller one > but also exhibits a higher radiation radiation resistance and hence lower > losses. > > Good luck with the experiments and let us know how you get on. > > 73, Brian VK3MI ZL1AZE > >> From: tsho...@wmata.com >> To: topband@contesting.com >> Date: Sat, 16 Jun 2012 13:28:38 + >> Subject: Topband: Receiving loops >> >> I want to try a new receiving antenna for the summer Stew Perry. Last >> winter was my first foray onto 160M and I really felt like an alligator. I >> could work everyone I could hear, with just 100W. I think that means I >> need a better receive antenna. If you look at my score in the winter Stew >> Perry I think I did great QSO-number wise, but my average distance was >> very poor, I'm guessing typical alligator. >> >> I have tried pennants and K9AY's over the winter with little success. >> Compared to my transmitting antenna (A "T" with a poor radial system) most >> signals were still better, S/N wise, on my transmitting antenna. I feel >> like I must've been doing something wrong. Still the fact that a few >> signals came in on the loop with by ear much better S/N, maybe I was on >> the right track and just didn't try hard enough. >> >> I will be trying a small tuned magnetic loop tonight (e.g. the last one at >> http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) >> . And maybe a terminated beverage but I'm limited to about 150'... well >> maybe I could run something longer down the driveway as long as I clean it >> up before the sun comes up and the neighbors see. >> >> I was fairly impressed with small tuned magnetic loops when I was doing >> some BCB DX'ing several years ago. I wasn't comparing with beverages or >> anything. >> >> Tim N3QE >> ___ >> UR RST IS ... ... ..9 QSB QSB - hw? BK > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Receiving antennas are about directivity, not sensitivity. That is the best way to reduce "noise" although a very small antenna can change the signal to noise ratio without being directional. Sent from my iPad On Jun 17, 2012, at 11:16, W2XJ wrote: > Sensitivity is not always important. Small loops in general receive less > noise and the real exercise is balancing the internal noise floor > against the actual signal received. In some cases a loss up to 20 db can > be acceptable the numbers are easy enough to run. > > On 6/16/12 8:17 PM, Brian Miller wrote: >> Hi Tim >> >> I also agree with the previous comments on this thread about detuning the >> transmit antenna (or any other wires/cables that are resonant on 160M) and >> isolating the coax feed line from the RX loop. >> >> It is also important to identify the direction of the main source of the >> noise and orientate the loop accordingly so that is being properly nulled. I >> use a small portable tuned loop to identify the direction of the noise.. >> >> Of course, if the noise is coming from the same direction as the DX then you >> are not going to see much (or any ) improvement in the signal-to-noise >> ratio. Also, if the noise sources are in multiple directions then it will >> also be difficult to null the noise properly. I have found that small tuned >> loops (with their bidirectional nulls) are often more effective in such a >> situation. >> >> One of the problems with small tuned loops made from wire is their low >> sensitivity. Rather than using a pre-amp you can boost the output by making >> the loop larger (e.g., a circumference of 0.1 wavelength or even larger). >> The larger loop maintains a directional pattern similar to the smaller one >> but also exhibits a higher radiation radiation resistance and hence lower >> losses. >> >> Good luck with the experiments and let us know how you get on. >> >> 73, Brian VK3MI ZL1AZE >> >>> From: tsho...@wmata.com >>> To: topband@contesting.com >>> Date: Sat, 16 Jun 2012 13:28:38 + >>> Subject: Topband: Receiving loops >>> >>> I want to try a new receiving antenna for the summer Stew Perry. Last >>> winter was my first foray onto 160M and I really felt like an alligator. I >>> could work everyone I could hear, with just 100W. I think that means I >>> need a better receive antenna. If you look at my score in the winter Stew >>> Perry I think I did great QSO-number wise, but my average distance was >>> very poor, I'm guessing typical alligator. >>> >>> I have tried pennants and K9AY's over the winter with little success. >>> Compared to my transmitting antenna (A "T" with a poor radial system) most >>> signals were still better, S/N wise, on my transmitting antenna. I feel >>> like I must've been doing something wrong. Still the fact that a few >>> signals came in on the loop with by ear much better S/N, maybe I was on >>> the right track and just didn't try hard enough. >>> >>> I will be trying a small tuned magnetic loop tonight (e.g. the last one at >>> http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) >>> . And maybe a terminated beverage but I'm limited to about 150'... well >>> maybe I could run something longer down the driveway as long as I clean it >>> up before the sun comes up and the neighbors see. >>> >>> I was fairly impressed with small tuned magnetic loops when I was doing >>> some BCB DX'ing several years ago. I wasn't comparing with beverages or >>> anything. >>> >>> Tim N3QE >>> ___ >>> UR RST IS ... ... ..9 QSB QSB - hw? BK >> >> ___ >> UR RST IS ... ... ..9 QSB QSB - hw? BK >> > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
If you are referring to a magnetic loop the problem is not the pickup from the shield - that is the conductor for picking up the signals - all signals including noise. The issue with a magnetic loop would be imbalance and that would be due to improper construction where the sides of the loop either way of the gap would not be equal or how you connect or install the tuning capacitor. Close proximity to a conducting surface would also affect the directivity. But even with a poorly constructed mag loop you should still get the null but it may not be symetrical or as deep as it should be. Sent from my iPad On Jun 16, 2012, at 10:36, Arthur Delibert wrote: > > Tim -- If the suggestions from others don't entirely do the trick, here's > another thing to consider: The outer conductor on your coax might be picking > up local noise and/or destroying the pattern of your receiving antenna. I DX > the AM broadcast band with whatever antennas I can fit into my suburban > backyard. I was getting poor results with a pennant until I put Radio Works > T-4 line isolators at both ends of the coax. Suddenly the antenna began to > behave as expected. Hope this helps. Art DelibertKB3FJO >> From: tsho...@wmata.com >> To: topband@contesting.com >> Date: Sat, 16 Jun 2012 13:28:38 + >> Subject: Topband: Receiving loops >> >> I want to try a new receiving antenna for the summer Stew Perry. Last winter >> was my first foray onto 160M and I really felt like an alligator. I could >> work everyone I could hear, with just 100W. I think that means I need a >> better receive antenna. If you look at my score in the winter Stew Perry I >> think I did great QSO-number wise, but my average distance was very poor, >> I'm guessing typical alligator. >> >> I have tried pennants and K9AY's over the winter with little success. >> Compared to my transmitting antenna (A "T" with a poor radial system) most >> signals were still better, S/N wise, on my transmitting antenna. I feel like >> I must've been doing something wrong. Still the fact that a few signals came >> in on the loop with by ear much better S/N, maybe I was on the right track >> and just didn't try hard enough. >> >> I will be trying a small tuned magnetic loop tonight (e.g. the last one at >> http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) . >> And maybe a terminated beverage but I'm limited to about 150'... well maybe >> I could run something longer down the driveway as long as I clean it up >> before the sun comes up and the neighbors see. >> >> I was fairly impressed with small tuned magnetic loops when I was doing some >> BCB DX'ing several years ago. I wasn't comparing with beverages or anything. >> >> Tim N3QE >> ___ >> UR RST IS ... ... ..9 QSB QSB - hw? BK > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Thanks. I wasn't referring to a magnetic loop that uses the shield for pickup. I was referring to the outer shield on the coax that runs from any antenna to the shack. If you use an antenna that was chosen for its specific directional and/or low-noise properties, and you don't isolate that antenna from the outer shield of the feedline, the shield itself becomes part of the antenna, spoils the directionality and picks up additional noise. Art DelibertKB3FJO > From: w...@aol.com > Date: Sun, 17 Jun 2012 11:52:38 -0400 > To: radio7...@msn.com > CC: topband@contesting.com; tsho...@wmata.com > Subject: Re: Topband: Receiving loops > > If you are referring to a magnetic loop the problem is not the pickup from > the shield - that is the conductor for picking up the signals - all signals > including noise. The issue with a magnetic loop would be imbalance and that > would be due to improper construction where the sides of the loop either way > of the gap would not be equal or how you connect or install the tuning > capacitor. Close proximity to a conducting surface would also affect the > directivity. But even with a poorly constructed mag loop you should still get > the null but it may not be symetrical or as deep as it should be. > > Sent from my iPad > > On Jun 16, 2012, at 10:36, Arthur Delibert wrote: > > > > > Tim -- If the suggestions from others don't entirely do the trick, here's > > another thing to consider: The outer conductor on your coax might be > > picking up local noise and/or destroying the pattern of your receiving > > antenna. I DX the AM broadcast band with whatever antennas I can fit into > > my suburban backyard. I was getting poor results with a pennant until I > > put Radio Works T-4 line isolators at both ends of the coax. Suddenly the > > antenna began to behave as expected. Hope this helps. Art DelibertKB3FJO > >> From: tsho...@wmata.com > >> To: topband@contesting.com > >> Date: Sat, 16 Jun 2012 13:28:38 + > >> Subject: Topband: Receiving loops > >> > >> I want to try a new receiving antenna for the summer Stew Perry. Last > >> winter was my first foray onto 160M and I really felt like an alligator. I > >> could work everyone I could hear, with just 100W. I think that means I > >> need a better receive antenna. If you look at my score in the winter Stew > >> Perry I think I did great QSO-number wise, but my average distance was > >> very poor, I'm guessing typical alligator. > >> > >> I have tried pennants and K9AY's over the winter with little success. > >> Compared to my transmitting antenna (A "T" with a poor radial system) most > >> signals were still better, S/N wise, on my transmitting antenna. I feel > >> like I must've been doing something wrong. Still the fact that a few > >> signals came in on the loop with by ear much better S/N, maybe I was on > >> the right track and just didn't try hard enough. > >> > >> I will be trying a small tuned magnetic loop tonight (e.g. the last one at > >> http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 transformer) > >> . And maybe a terminated beverage but I'm limited to about 150'... well > >> maybe I could run something longer down the driveway as long as I clean it > >> up before the sun comes up and the neighbors see. > >> > >> I was fairly impressed with small tuned magnetic loops when I was doing > >> some BCB DX'ing several years ago. I wasn't comparing with beverages or > >> anything. > >> > >> Tim N3QE > >> ___ > >> UR RST IS ... ... ..9 QSB QSB - hw? BK > > > > ___ > > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
Agreed. Wasn't sure of which. On my flags and pennants I have no shield pick up which I account to both using well designed 16:1 transformers with isolated windings and having the coax run under ground much of the route back inside. Sent from my iPad On Jun 17, 2012, at 16:09, Arthur Delibert wrote: > Thanks. I wasn't referring to a magnetic loop that uses the shield for > pickup. I was referring to the outer shield on the coax that runs from any > antenna to the shack. If you use an antenna that was chosen for its specific > directional and/or low-noise properties, and you don't isolate that antenna > from the outer shield of the feedline, the shield itself becomes part of the > antenna, spoils the directionality and picks up additional noise. > > Art Delibert > KB3FJO > > > From: w...@aol.com > > Date: Sun, 17 Jun 2012 11:52:38 -0400 > > To: radio7...@msn.com > > CC: topband@contesting.com; tsho...@wmata.com > > Subject: Re: Topband: Receiving loops > > > > If you are referring to a magnetic loop the problem is not the pickup from > > the shield - that is the conductor for picking up the signals - all signals > > including noise. The issue with a magnetic loop would be imbalance and that > > would be due to improper construction where the sides of the loop either > > way of the gap would not be equal or how you connect or install the tuning > > capacitor. Close proximity to a conducting surface would also affect the > > directivity. But even with a poorly constructed mag loop you should still > > get the null but it may not be symetrical or as deep as it should be. > > > > Sent from my iPad > > > > On Jun 16, 2012, at 10:36, Arthur Delibert wrote: > > > > > > > > Tim -- If the suggestions from others don't entirely do the trick, here's > > > another thing to consider: The outer conductor on your coax might be > > > picking up local noise and/or destroying the pattern of your receiving > > > antenna. I DX the AM broadcast band with whatever antennas I can fit into > > > my suburban backyard. I was getting poor results with a pennant until I > > > put Radio Works T-4 line isolators at both ends of the coax. Suddenly the > > > antenna began to behave as expected. Hope this helps. Art DelibertKB3FJO > > >> From: tsho...@wmata.com > > >> To: topband@contesting.com > > >> Date: Sat, 16 Jun 2012 13:28:38 + > > >> Subject: Topband: Receiving loops > > >> > > >> I want to try a new receiving antenna for the summer Stew Perry. Last > > >> winter was my first foray onto 160M and I really felt like an alligator. > > >> I could work everyone I could hear, with just 100W. I think that means I > > >> need a better receive antenna. If you look at my score in the winter > > >> Stew Perry I think I did great QSO-number wise, but my average distance > > >> was very poor, I'm guessing typical alligator. > > >> > > >> I have tried pennants and K9AY's over the winter with little success. > > >> Compared to my transmitting antenna (A "T" with a poor radial system) > > >> most signals were still better, S/N wise, on my transmitting antenna. I > > >> feel like I must've been doing something wrong. Still the fact that a > > >> few signals came in on the loop with by ear much better S/N, maybe I was > > >> on the right track and just didn't try hard enough. > > >> > > >> I will be trying a small tuned magnetic loop tonight (e.g. the last one > > >> at http://www.w8ji.com/magnetic_receiving_loops.htm with the 9:1 > > >> transformer) . And maybe a terminated beverage but I'm limited to about > > >> 150'... well maybe I could run something longer down the driveway as > > >> long as I clean it up before the sun comes up and the neighbors see. > > >> > > >> I was fairly impressed with small tuned magnetic loops when I was doing > > >> some BCB DX'ing several years ago. I wasn't comparing with beverages or > > >> anything. > > >> > > >> Tim N3QE > > >> ___ > > >> UR RST IS ... ... ..9 QSB QSB - hw? BK > > > > > > ___ > > > UR RST IS ... ... ..9 QSB QSB - hw? BK > > ___ > > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
> Thanks. I wasn't referring to a magnetic loop that uses the shield for > pickup. I was referring to the outer shield on the coax that runs from > any antenna to the shack. If you use an antenna that was chosen for its > specific directional and/or low-noise properties, and you don't isolate > that antenna from the outer shield of the feedline, the shield itself > becomes part of the antenna, spoils the directionality and picks up > additional noise. Art DelibertKB3FJO Not necessarily. If the antenna is properly balanced, or properly unbalanced, that should be all the isolation necessary. Beverages are sensitive to common mode because people use autotransformers, or share a common shield and antenna ground, and the antenna almost always has a poor ground. So the antenna is nether balanced, no unbalanced, but is somewhere between and the shield has a connection to the antenna's ground. A small loop, if properly built, should be immune to common mode on the feeder. It is also more difficult to fix a problem in loop design by throwing beads on a cable, because loop common mode impedance is so high the beads are a tiny part of the CM system impedance. Adding a ground rod at the antenna, where the cable comes vertically to the earth, would probably be more effective with a small loop than beads. I never have needed additional isolation on a small loop, but I've never gapped the loop at the wrong place, or built a poorly balanced loop. PS Why do my posts take so long to appear on the reflector? Is this normal? 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Receiving loops
I'm the guy in MD with the 140 foot BOG. Mike is correct. My BOG works good on 160, better on 80, and best on 40. Very low noise levels with improved snr on all 3 bands. I feed it with cheap quad shield RG6. Best of all the antenna is invisible to the XYL as it lives on the opposite side of our privacy fence. Mike can set you up with the proper transformers and terminating resistors. On Sat, 2012-06-16 at 08:35 -0500, Mike Waters wrote: > Why don't you try a 150' BOG? I know a guy in Maryland who has one only > 140' long, and he hears DX on it on 160 that he doesn't on his inverted-L. > > Probably better than a BOG is a Slinky Beverage. > > 73, Mike > http://www.w0btu.com/Beverage_antennas.html > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Receiving Antenna Metrics With Examples Webinar
The World Wide Radio Operators Foundation (WWROF) is pleased to present the following Webinar. Date - Tuesday, February 13 Time - 19:00 UTC Registration - https://register.gotowebinar.com/register/6004189296300531458 Jukka OH6LI shares a presentation about receiving antennas. Gain and front-to-back are well established specifications. Some have used Receiving Directivity Factor, RDF as a receiving antenna metric. Now we have also the DMF. The Directivity Merit Figure algorithm is shown in an Excel tool for the first time. The Receiving Antenna Metrics Excel workbook is EZNEC and MMANA compatible. Presentation includes new metrics Noise Margin and Leaking Index. A number of antennas will be used as examples. The examples begin with residential area level solutions, extending to staggered beverages and beyond. Please note that this presentation will be recorded and available for playback at your convenience on the WWROF webpage: http://wwrof.org/category/webinar-archive/ 73 Ken K4ZW _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Receiving loop worked great in Stew Perry
In rebuilding the station this year, I have been trying a lot of receiving antennas. My criterion was: does this receive significantly better than the transmit vertical. I tried some beverages without success. In the past they had been good at times. I tried a low 80 meter dipole that I happened to have. That was somewhat useful. For the SP, I put up a low 160 meter dipole. It loaded up so well I could have used it for a transmit antenna. Surprisingly, it was only 10 dB below the 60 foot transmit vertical. I had expected 20 dB. But on receive, it was no better than the vertical. The big surprise was the receiving loop. This is the one shown on the cover of NCJ a few years ago. It was phenomenal for receiving. Signals that were barely audible on the vertical popped out of the noise on the loop and were Q5. I used it for the entire contest, occasionally checking it against the vertical. I don't like to think that certain antennas are magic but by golly this thing really works. I did rotate it for minimum power line noise, which ended up having it broadside to a power pole I have had trouble with before. It was also approximately broadside to VK6GX, but I had no trouble logging him around 1200Z. I appreciated not having to switch between beverages, which has probably caused me to miss VK's in the past. In theory, the loop should not be much different than a vertical. What explains this? I am thinking about trying it at 30 foot height instead of ground mounted. Has anyone tried this? Rick N6RK ___ Stew Perry Topband Distance Challenge coming on December 29th.
Re: Topband: Receiving loop worked great in Stew Perry
If you have nasty and persistent local Electical noise ie from arcing insulators and nearby electrical crud from devices and a constant s9 or strong noise floor the mag loop will work wonders only because it can null the strongest of the noise (or all if in same direction) and present a superior s/n situation. I've seen the tiny indoor loops do that too. The mag loop is completely omnidirectional in both vertical and horizontal planes except for the two end nulls so its no match for a full k9ay or terminated loop, flag, pennant etc which has a lot more vertical plan discrimination however they can't really null that strong very local Electical crud. Sent from my iPhone On Dec 31, 2012, at 11:30 PM, "Richard (Rick) Karlquist" wrote: > In rebuilding the station this year, I have been trying a lot of receiving > antennas. My criterion was: does this receive significantly > better than the transmit vertical. I tried some beverages without > success. In the past they had been good at times. I tried a low 80 > meter dipole that I happened to have. That was somewhat useful. > For the SP, I put up a low 160 meter dipole. It loaded up so well > I could have used it for a transmit antenna. Surprisingly, it was > only 10 dB below the 60 foot transmit vertical. I had expected 20 dB. > But on receive, it was no better than the vertical. > > The big surprise was the receiving loop. This is the one shown > on the cover of NCJ a few years ago. It was phenomenal for receiving. > Signals that were barely audible on the vertical popped out of the noise > on the loop and were Q5. I used it for the entire contest, occasionally > checking it against the vertical. I don't like to > think that certain antennas are magic but by golly this thing really > works. I did rotate it for minimum power line noise, which ended > up having it broadside to a power pole I have had trouble with before. > It was also approximately broadside to VK6GX, but I had no trouble > logging him around 1200Z. I appreciated not having to switch between > beverages, which has probably caused me to miss VK's in the past. > > In theory, the loop should not be much different than a vertical. > What explains this? > I am thinking about trying it at 30 foot height instead of ground > mounted. Has anyone tried this? > > Rick N6RK > ___ > Stew Perry Topband Distance Challenge coming on December 29th. ___ Stew Perry Topband Distance Challenge coming on December 29th.
Re: Topband: Receiving loop worked great in Stew Perry
Here is a link to the NCJ article describing the loop: http://www.n6rk.com/loopantennas/NCJ_loop_antenna_N6RK.pdf Rick N6RK ___ Stew Perry Topband Distance Challenge coming on December 29th.
Re: Topband: Receiving loop worked great in Stew Perry
Hello Rick, I've tried also a K9AY such loop on the past SP contest and was a good improvement over my INV-L. I never heard before CE1/K7CA and south american DX stations. An A/B test were "all to nothing" for K9AY loop comparing with INV-L for many times. Due to local constraint, I'm using a single loop on E-W switchable configuration. The F/B is about 15 to 25dB measured on MW BC band. Despite it is mounted on the INV-L near field (about 25 meters away), the mutual coupling does not damage too much the radiation pattern. I suggest to everyone who does not try a receiving antenna on 160m to give it a try. It will make a BIG difference. 73 de YO3FFF Cristi === Here is a link to the NCJ article describing the loop: http://www.n6rk.com/loopantennas/NCJ_loop_antenna_N6RK.pdf Rick N6RK ___ Stew Perry Topband Distance Challenge coming on December 29th. ___ Stew Perry Topband Distance Challenge coming on December 29th.
Topband: Receiving loop comparison: Pixel vs 20 ft and 40 ft passive loops (long)
For the second night of the ARRL contest, I set up three receiving loops with a switch to compare them in real time. A Pixel circular loop (10 foot perimeter) using the 30 dB Clifton Labs preamp that comes with it was the first antenna. The second one was a square 20 foot perimeter shielded loop as I described in the Sept./Oct. 2009 National Contest Journal: http://www.n6rk.com/loopantennas/NCJ_loop_antenna_N6RK.pdf) The third antenna was a square 40 foot version of the loop in the NCJ article. No external preamp was used with the 20 and 40 foot loops. The receiver was a Yaesu FT-1000 with its internal preamp turned on. All three loops were oriented to null at 30 degrees azimuth on ground wave, which minimizes the noise at this QTH. After comparisons on dozens of stations in the contest, the clear winner was the 40 foot loop. In general, the noise levels of the Pixel and the 40 foot loop were similar. However, the latter had 6 to 10 dB more signal, resulting in a markedly improved S/N ratio. There were numerous stations where a signal that was Q5 on the 40 foot loop was inaudible on the Pixel. I ended up just leaving the switch on the 40 foot loop for the balance of the contest. If I had to have only one loop to use, it would be an easy decision to go with the 40 foot one. The 20 foot loop had signal levels comparable to the Pixel, but the noise level was considerably lower. It came in 2nd place. The signal level of the 20 foot loop has always been marginal for the FT-1000 without external preamp. It might help to have some preamplification on it. I would rather use a larger loop than fool with a preamp. We have strong BCB signals, including one at 1,700 kHz, so preamps are always problematical. The 40 foot loop will work (on 160 meters only) with an unmodified antenna circuit board, however, I ran into BCB QRM of the tuning diodes. I removed one of the two tuning diodes, which allowed the tuning voltage to rise. This helped on the BCB QRM, but there was still some lite hash heard. Finally, I went to four diodes in a series parallel configuration as described in the article. This fixed the BCB QRM. The final configuration tunes from about 1.25 to 2.5 MHz, covering WWV. I also compared to the transmit vertical. In most cases, stations could be copied on the vertical, but maybe not at 100%, and even when they could be copied, there was the usual unpleasant impulsive noise, as compared to the gentle rushing noise of the loops. From a listening fatigue aspect, it is not good to have to listen on the vertical. I have no technical theory to explain why this is, I just observe it consistently. The Pixel loop covers all the way to 30 MHz. It still may be a useful receive antenna on the higher bands. When I purchased it for evaluation, I suspected that 160 meters was not its strong suit. Below 160 meters on BCB, the signals are much stronger and the Pixel should have no problem. Thus the take away is only that the Pixel isn't very useful on 160 meters. The mechanical construction of the 40 foot version is much more difficult that the 20 foot version. My initial attempt was successful enough for these tests, but was basically a discovery of what NOT to do. It did become clear that it is much easier to guy the vertical support rather than making it self supporting. I am interested in hearing about successful large loop construction techniques. Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
