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Loop Antennas
On Tue, 8 Nov 2005 13:51:06 -0800, "Michael" wrote:
I get a lot of noise from my random wire antenna. It transmits very well but is very noisy in receive. My neighbor put up a 280 foot loop antenna which Ok. he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his So, the noise is "profoundly" less (whatever that means), but what about signals that you want to hear, and how does it perform transmitting. You see, a 30dB attenuator would profoundly reduce the noise.... and the desired receive signals, and the tx signal, but it isn't necessarily better. You probably know the answers, you just didn't tell us. It is often the case that the best antenna for transmission is the one that makes the most noise where you want to be heard, and the best antenna for receiving is the one that gives the best S/N ratio (not necessarily the best S meter deflection) for stations from that place, and they may not be the same antenna. Owen -- |
Loop Antennas
Michael wrote:
Has anybody else had this experience with loops? Only the past three generations. :-) -- 73, Cecil http://www.qsl.net/w5dxp |
Loop Antennas
Ah yes grasshopper - zee loops - zay are good.
The loop helps reduce noise since its dc-shorted and no static buildup, and your socks won't stick to it. ;-) but it takes more trees to hold it up "Michael" wrote in message ... I get a lot of noise from my random wire antenna. It transmits very well but is very noisy in receive. My neighbor put up a 280 foot loop antenna which he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his house at a 30 ft. height. It is arranged in a square. Has anybody else had this experience with loops? It looks like I have room to put up a triangular loop. Will this work as well? Can I use the same tuner I have now and just feed a coax into a balun. Or, should I put the balun in the tuner and come straight out with ladder line? There is a lot of room in this tuner. It is an old remote controlled tuner surplused from a ship. |
Loop Antennas
Michael,
I've had sort of the same experience with a loop antenna. I'd say it was probably about the same for most everyone. As far as where to put the balun and how to feed the thing, I honestly don't think it's going to make much difference. What would be easiest and 'best' for you? That's how I'd do it... 'Doc PS - Are loops the 'end-all of antennas? Huh, good question, and the answer is probably, no. But, I've had good luck with mine... |
Loop Antennas
On 2005-11-08, Michael wrote:
Has anybody else had this experience with loops? It looks like I have room to put up a triangular loop. Will this work as well? Can I use the same tuner I have now and just feed a coax into a balun. Or, should I put the balun in the tuner and come straight out with ladder line? Following Walt's (W2DU) ideas, I have a 259' horizontal delta (triangle) loop (two trees and a wooden pole) fed at almost middle of one side (convenience, not design) by 450 ohm ladder line. This is soldered directly to a ferrite bead choke balun (ala W2DU) which, via PL-259s and barrel connector, goes to a very short piece of 50 ohm coax (about 6') directly into the house to the unbalanced SO-239 input of my MFJ-941E. Works like a charm on all bands 80-10m, no RF in the room, and good signal reports. ....Edwin, KD5ZLB -- __________________________________________________ _____ "Once you have flown, you will walk the earth with your eyes turned skyward, for there you have been, there you long to return."-- da Vinci ... www.shreve.net/~elj |
Loop Antennas
Michael.
Why not try a folded dipole made from 300 ohm TV twin lead? Cut it for the band you are interested in. A tuner or a balun to 52 ohm coax to match your rig will be necessary. I was impressed with the lack of noise pickup from the one I put up a couple of years ago. Cut for 75 meters. My home and antenna are just a hundred feet or so from a power line with 3 sets of high voltage lines and sometimes they are very noisy on a regular dipole, but not the folded dipole. Paul, KD7HB |
Loop Antennas
I get a lot of noise from my random wire antenna. It transmits very well but
is very noisy in receive. My neighbor put up a 280 foot loop antenna which he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his house at a 30 ft. height. It is arranged in a square. Has anybody else had this experience with loops? It looks like I have room to put up a triangular loop. Will this work as well? Can I use the same tuner I have now and just feed a coax into a balun. Or, should I put the balun in the tuner and come straight out with ladder line? There is a lot of room in this tuner. It is an old remote controlled tuner surplused from a ship. |
Loop Antennas
"I get a lot of noise from my random wire antenna. It transmits very well but is very noisy in receive. My neighbor put up a 280 foot loop antenna which Ok. he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his So, the noise is "profoundly" less (whatever that means), but what about signals that you want to hear, and how does it perform transmitting. Well, I would not be raving about his antenna if it also reduced the signals you want to hear. He gets the same kind of signal reports that I do. We were both on the same net one night and we were both be received equally at various spots. Clearly, mine transmits as well as his. You see, a 30dB attenuator would profoundly reduce the noise.... and the desired receive signals, and the tx signal, but it isn't necessarily better. When I listened to our local North Dakota Data Net, I heard all the checkins like they were much much closer. No Noise! I should have been more specific. The S?n ratio was profoundly better than my puny random wire. However, I do not know yet if I am up to putting up 3 or 4 32 foot poles or higher. What a drag. I will probably do this next spring. It is getting too cold to make the task a very pleasant one now. You probably know the answers, you just didn't tell us. It is often the case that the best antenna for transmission is the one that makes the most noise where you want to be heard, and the best antenna for receiving is the one that gives the best S/N ratio (not necessarily the best S meter deflection) for stations from that place, and they may not be the same antenna. Owen -- |
Loop Antennas
"Hal Rosser" wrote in message . .. Ah yes grasshopper - zee loops - zay are good. The loop helps reduce noise since its dc-shorted and no static buildup, and your socks won't stick to it. ;-) but it takes more trees to hold it up Oh thank you Master Rosser. I am a little wiser now. How long before I can take the pebble from your hand or maybe just kick butt? |
Loop Antennas
Michael wrote:
I had never hear of a loop antenna back in the 50s. Loops started to come into their own with the invention by C. C. Moore of the Cubical Quad circa 1939. -- 73, Cecil http://www.qsl.net/w5dxp |
Loop Antennas
See this link for some more info
http://lists.contesting.com/archives.../msg00393.html "Cecil Moore" wrote in message . com... Michael wrote: I had never hear of a loop antenna back in the 50s. Loops started to come into their own with the invention by C. C. Moore of the Cubical Quad circa 1939. -- 73, Cecil http://www.qsl.net/w5dxp |
Loop Antennas
I appreciate all the comments very much. A folded dipole would be easier for
me. I will discuss this with my neighbor W0BBN. He has been using a loop for 20 years. It sounds like it is hard to go wrong if you are willing to put out the work for a loop antenna. I have been away from low band work since I started college. That has been very very long ago. I had never hear of a loop antenna back in the 50s. There was no internet and other hams were few and far between where I lived in the country. |
Loop Antennas
The loop is a DC short and is very quiet. You can also feed it with a
quarter wave section of 75 ohm coax using (quarter wave length x Velocity of coax) as the length of the matching section. Good luck, Bill, W4WNT "Michael" wrote in message ... I get a lot of noise from my random wire antenna. It transmits very well but is very noisy in receive. My neighbor put up a 280 foot loop antenna which he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his house at a 30 ft. height. It is arranged in a square. Has anybody else had this experience with loops? It looks like I have room to put up a triangular loop. Will this work as well? Can I use the same tuner I have now and just feed a coax into a balun. Or, should I put the balun in the tuner and come straight out with ladder line? There is a lot of room in this tuner. It is an old remote controlled tuner surplused from a ship. |
Loop Antennas
"Michael" wrote in
: I get a lot of noise from my random wire antenna. It transmits very well but is very noisy in receive. My neighbor put up a 280 foot loop antenna which he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his house at a 30 ft. height. It is arranged in a square. Has anybody else had this experience with loops? It looks like I have room to put up a triangular loop. Will this work as well? Can I use the same tuner I have now and just feed a coax into a balun. Or, should I put the balun in the tuner and come straight out with ladder line? There is a lot of room in this tuner. It is an old remote controlled tuner surplused from a ship. Michael, a horizontal full-wave loop is actually quite a good choice for LOCAL networking on 75m. The feedpoint impedance will depend somewhat on the distance above ground and on the quality of the ground but should range between about 200 ohms down to as low as about 50 (or even lower if your ground is good). The shape of the loop is not all that important and, if it's symmetric, the feedpoint can be anywhere. The ideal height would be about 65 feet, but lower will still work well. The radiation characteristic of an antenna like this is horizontal polarization but with the main lobe directly skyward (which is actually a good thing on 75m for LOCAL work). It does this, of course, at the expense of radiation at low angles, so it is not a useful DX antenna (though it may outperform a dipole at the same height). Being a loop, it is also somewhat immune to near-field electrostatic interference such as from nearby power lines (which may account for the lower noise pickup). -- Dave Oldridge+ ICQ 1800667 |
Loop Antennas
Sound like your discribing my station setup. I also use a Delta loop in the
shape of a diamond with the highest point at approximately 70 feet and the lowest opposite corner is about 40 feet, both above ground. Now it gets interesting as this set up is likely about 5 feet lower than the closest neighbouring amateur's basement floor is and I still out perform his inverted V. But the my loop is a full wave on 80 meters and I have a rather uneak piece of property. My soil is very good conductively and my ground happens to be a creek bed with a 8 inch water pipe submerged in the creek which runs all year round with about a foot of water over the pipe. Also when I was looking for property I drove my van in to the property as far as I could and call CQ on my mobile hf. Made a contact in Glasglow, Moscow and Japan. I bought the property that afternoon. And I haven't stopped enjoying the bands even when we are at the low side of a cycle. I've also played with a number of antennas and always came back to the delta loop or a four square. I'm planning on putting up a full wave delta loop for 160 meters this spring. My present loop is hooted up to a homebrew 4:1 balun with 300 ohm foam then a 10 foot piece of 9913 coax to a At-180 Icom tuner to a IC-706MKIIG. On a bad night I can make contacts about the Mississippe to Hawai, on a good night Europe and the Globe. If you have the room they are one of the best antennas for the money invested. But you still have to have a good location and a good ground, if your missing either there isn't an antenna in the world that will help you. By the way I'm 147 feet above sea level and my closest neighbouring amateur is 177 feet and his antenna is 30 feet above that, but I still out preform him hands down on any and all bands. Anyway this is what it's all about, haveing fun and making new friends. 73...de ve7agw, Al Vancovuer Island, BC "Michael" wrote in message ... I get a lot of noise from my random wire antenna. It transmits very well but is very noisy in receive. My neighbor put up a 280 foot loop antenna which he feeds with ladder line. He feeds the ladder line from a 4 to 1 balun to coax. The coax comes from a tuner. His setup performs very well on all bands down to 75 meters. I went over to his shack last night and listened to his receiver on 75. I was really impressed with the lack of noise. I can safely say the difference in noise was profound. He has this loop surrounding his house at a 30 ft. height. It is arranged in a square. Has anybody else had this experience with loops? It looks like I have room to put up a triangular loop. Will this work as well? Can I use the same tuner I have now and just feed a coax into a balun. Or, should I put the balun in the tuner and come straight out with ladder line? There is a lot of room in this tuner. It is an old remote controlled tuner surplused from a ship. |
Loop Antennas
What I find amazing is that "Michael" leaves the impression that he is in ND
when his neighbor W0BBM is in north central Kansas with two whole states in between. It gives a whole new meaning to "neighbor." Hard to compare antennas when the neighboring antennas are so far apart. 73, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Michael" wrote in message ... I appreciate all the comments very much. A folded dipole would be easier for me. I will discuss this with my neighbor W0BBN. He has been using a loop for 20 years. It sounds like it is hard to go wrong if you are willing to put out the work for a loop antenna. I have been away from low band work since I started college. That has been very very long ago. I had never hear of a loop antenna back in the 50s. There was no internet and other hams were few and far between where I lived in the country. |
Loop Antennas
Being a loop, it
is also somewhat immune to near-field electrostatic interference such as from nearby power lines (which may account for the lower noise pickup) Dunno...I consider this to be fictional content... They may be slightly quieter as far as corona buildup, or charge on the antenna itself, but not any noise in the far or near field. If a loop picks up less noise in a certain direction vs another antenna, it's the inferior antenna in that direction. Noise is rf, and a signal, the same as any other signal. If you get rid of noise, you get rid of *any* signal in that direction and angle. I also consider the magic noise reducing qualities of the "shielded" loops to be a fairy tale also. I've done a good bit of testing, and can see no indication that a shielded loop is any "quieter" than a regular unshielded loop. The shielded loop design promotes good balance. But good balance can be had with any loop. I guess loops are ok, and they are efficient when fed with coax, same as a dipole, but I usually prefer dipoles on 80m. If you run a loop for NVIS, you want it all high up in the air, with no parts dragging towards ground. Many stick loops in the yard, and some parts will be high, some parts low. The current distribution is "fairly" constant around the loop, vs max on the dipole being at the feed point. So you have more chances of increased ground and clutter loss with the loops in many cases. I prefer the dipoles and inv vees because the maximum current point is up high at the apex, and the ends of the wires, which may droop lower, are voltage nodes. I'd rather have the bulk of my radiation high up in the air, rather than spread helter skelter around the yard area. Often the dipole will outperform such a draggy loop... But if all the loop is high and well supported, they can be worthwhile. But still more work for little if any real increase in performance vs the dipole. MK |
Loop Antennas
Cec, in this little country we don't seem to suffer from static from
dust or other dry storms. Rather rarely, when a thunderstorm is in the vicinity, I have experienced rain-static which occurs only during a heavy 'tropical' downpour. At such times I am inclined to disconnect the antenna, anyway, to avoid damage due to a direct lightning strike on the antenna or house. The S-meter may rise to S-10 or S-11 for a few minutes but this extreme occurs only once every few years. I have never experienced static due to dry snow. I have only once experienced static on a nice warm day with a completely blue sky and this lasted only for half an hour. Never figured out why. Using a high value resistor or choke to ground the antenna doesn't have any effect on S-meter noise level. I would not expect it to. I cannot see how loop antennas are less susceptible to static except that their smaller size may have a smaller catchment area for particles or raindrops. Could you briefly describe what happens to the S-meter on the 160, 80 and 40 meter bands when severe static occurs in Texas, or any other States, and how frequently static weather conditions occur strong enough to temporally put one off the air? ---- Reg. |
Loop Antennas
Reg Edwards wrote:
Could you briefly describe what happens to the S-meter on the 160, 80 and 40 meter bands when severe static occurs in Texas, or any other States, and how frequently static weather conditions occur strong enough to temporally put one off the air? On my IC-745 in AZ, the coax connector would arc many times at the transceiver about once a month during late summer. It pinned the S-meter but didn't seem to damage the IC-745. It arced whether the IC-745 was on or off. A 4:1 voltage balun cured that particular arcing problem although it generated other problems. The PL-239 coax connectors must arc around 300 volts or so. -- 73, Cecil http://www.qsl.net/w5dxp |
Loop Antennas
Heck, next time a T-storm rolls through, I'll record it ,
and let you hear it. Simple to do with my radio running through the sound card. I can compress the file to mp3 to save DL time. No unzipping required. MK |
Loop Antennas
Now that we have heard all the benefits of various loop antennas, I
have a question about the physical part of the antenna. I am planning on erecting an 80 meter or perhaps 160 meter square loop antenna. The question is how have you fixed the corners of your loop antenna? Can the antenna wire move in the insulator so as to equalize the force on each side? Or is the insulator in the corner fastened tightly to the antenna wire? Also, what type of insulators are your using in the corners? Ceramic compression? Glass, Other type ceramic? Anyone using plastic insulators? TIA Paul, KD7HB Redmond, OR |
Loop Antennas
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Loop Antennas
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Loop Antennas
Paul,
It really doesn't matter to much how you prepare or fix the corners. I have used free floating and fastened down tight. If they are in the trees sooner of later the wire will snap regardless of how you have the corners prepared. The alpha-delta cin insulator from Radio Works $1.50 are very good one to consider using. Larry/W4LM wrote in message oups.com... Now that we have heard all the benefits of various loop antennas, I have a question about the physical part of the antenna. I am planning on erecting an 80 meter or perhaps 160 meter square loop antenna. The question is how have you fixed the corners of your loop antenna? Can the antenna wire move in the insulator so as to equalize the force on each side? Or is the insulator in the corner fastened tightly to the antenna wire? Also, what type of insulators are your using in the corners? Ceramic compression? Glass, Other type ceramic? Anyone using plastic insulators? TIA Paul, KD7HB Redmond, OR |
Loop Antennas
wrote in message
oups.com... Now that we have heard all the benefits of various loop antennas, I have a question about the physical part of the antenna. I am planning on erecting an 80 meter or perhaps 160 meter square loop antenna. The question is how have you fixed the corners of your loop antenna? Can the antenna wire move in the insulator so as to equalize the force on each side? Or is the insulator in the corner fastened tightly to the antenna wire? Also, what type of insulators are your using in the corners? Ceramic compression? Glass, Other type ceramic? Anyone using plastic insulators? TIA Paul, KD7HB Redmond, OR Hi Paul and the group, I let my corners float and all I use are pvc 1/2 or 3/4 pipe 90 deg. elbows with dacron rope tied to around them then flug over a tree. Been using this method for years. No pulleys or extra fancy methods just rope and a elbow, this way I can move the antenna around if I choose to change my feed point at any time. Also allows for the stresses to even themselves out between the trees depending on how the wind blows. Although one tree is a very small sapling that stands about 40 feet high and the other three trees can pull it via the antenna wire with no great effort at all. Also have enough slack in the antenna to allow for rapid wind changes. Everyone has a different method and most are very good and serve the purpose they were intended to, one persons idea may not work in another area, but to each his own method works otherwise there would be a lot of trial and error going on, hi hi. Been there done that and got the hat to show for it to. I'm fortunate in my area as I don't get much wind at all, although I have used a similar method on the west coast of Vancouver Island with weighted milk jugs instead of tying off the support line for two of the four support lines. 73...de ve7agw, Al Port Alberni, BC |
Loop Antennas
Al, VE7AGW wrote:
"I have used a similar method on the west coast of Vancouver Island with weighted milk jugs, instead of tying off the support line for two of the four support lines." I just heard Ray Price sing "For the Good Times" on KKYX, San Antonio, 680 KHz. The station is 200 miles from here. The sntenna is the built-in loopstick in the radio. I listen 24 hours, all country msic, all the time for more thann 32 years. Best regards, Richard Harrison, KB5WZI |
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