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Grounding
Will be using a long wire strung around inside of the house for now when I
get my tabletop. Where the radio will be there are no pipes etc, what is the best way to ground, can I use the center screw of the electric outlet. Been using protables now & a set top with a whip built in antenna (RS394). |
Grounding
On Thu, 08 Dec 2005 13:02:01 GMT, "Steve Rabinowitz"
wrote: Will be using a long wire strung around inside of the house for now when I get my tabletop. Where the radio will be there are no pipes etc, what is the best way to ground, can I use the center screw of the electric outlet. Been using protables now & a set top with a whip built in antenna (RS394). Only if your mains wiring is in metallic pipe or raceways. Otherwise I'd run a discrete wire. |
Grounding
Is there any where in the house or must I attch to a metal stake in the
ground. Would rather not run the wire outside, "David" wrote in message ... On Thu, 08 Dec 2005 13:02:01 GMT, "Steve Rabinowitz" wrote: Will be using a long wire strung around inside of the house for now when I get my tabletop. Where the radio will be there are no pipes etc, what is the best way to ground, can I use the center screw of the electric outlet. Been using protables now & a set top with a whip built in antenna (RS394). Only if your mains wiring is in metallic pipe or raceways. Otherwise I'd run a discrete wire. |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
SR,
Vice using the questionable the Ground {Green Wire} of your Household AC Power System. Why not consider a simple Around-the-Room {Ceiling Level} Horizontal [Flat] Loop Antenna. The Loop Antenna is consider a 'blanced' Antenna that does not require a Ground and is Horizontally Polarized so it generally pick-up less man made noise. The "In-Door" Horizontal [Flat] Loop Antenna is easy to build; usually is relatively long 40-60 Feet for an In-Door Antenna; and relatively lower noise pick-up to an in-door vertical antenna or long wire antenna. The Radio or Receiver can be run off of AC with an AC Ground connection via the AC Power Plug or DC without any Ground connection at all. something to consider - iane ~ RHF |
Grounding
Dear Steve,
If you run any kind of wire in your house, you probably will not need any grounding at all. Just to check, however, try the radio without grounding at first and then try hooking up a ground and see if there is any improvement or any difference at all. (The ground on your electrical outlet is fine for this experiment.) RHF and BPNJensen's posts are also correct. A loop antenna used inside a house may give better performance than just plain wire run randomly and loops generally need no grounding. As a matter of fact, in my personal experience, a loop antenna, indoors or outdoors, will afford much better reception quality (S/N ratio) than long wires in areas where there is a great deal of local electrical interference as loops tend to "reject" such interference. You might want to try to make (or buy) a loop antenna and mount it in a window. There are several sources on the web for instructions and a very good book is Joe Carr's LOOP ANTENNA HANDBOOK. Do try a good antenna on your Satellit 800. I think you'll be very pleased. Best, Joe |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
"RHF" wrote in message oups.com... SR, Vice using the questionable the Ground {Green Wire} of your Household AC Power System. Why not consider a simple Around-the-Room {Ceiling Level} Horizontal [Flat] Loop Antenna. The Loop Antenna is consider a 'blanced' Antenna that does not require a Ground and is Horizontally Polarized so it generally pick-up less man made noise. The "In-Door" Horizontal [Flat] Loop Antenna is easy to build; usually is relatively long 40-60 Feet for an In-Door Antenna; and relatively lower noise pick-up to an in-door vertical antenna or long wire antenna. The Radio or Receiver can be run off of AC with an AC Ground connection via the AC Power Plug or DC without any Ground connection at all. something to consider - iane ~ RHF . . RHF, This is the first time I recall you *not* posting a link to materials/instructions for building the antenna you recommended in your reply. It seems like one I've seen you refer to previously, but darned if I can find it in my saved newsgroup messages. |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
The loop will be unbalanced if you don't use a balun. Of course, my
solution is to buy the Wellbrook ALA100. At 40ft of wire, I find two BCB stations about 20 miles away force my 7030 to switch on the attenuator. I have maybe 10db before the s-meter is pegged, so I wouldn't go much beyond 60ft if you get the wellbrook. RHF wrote: SR, Vice using the questionable the Ground {Green Wire} of your Household AC Power System. Why not consider a simple Around-the-Room {Ceiling Level} Horizontal [Flat] Loop Antenna. The Loop Antenna is consider a 'blanced' Antenna that does not require a Ground and is Horizontally Polarized so it generally pick-up less man made noise. The "In-Door" Horizontal [Flat] Loop Antenna is easy to build; usually is relatively long 40-60 Feet for an In-Door Antenna; and relatively lower noise pick-up to an in-door vertical antenna or long wire antenna. The Radio or Receiver can be run off of AC with an AC Ground connection via the AC Power Plug or DC without any Ground connection at all. something to consider - iane ~ RHF . . . . . |
Grounding
On Thu, 08 Dec 2005 13:02:01 GMT, "Steve Rabinowitz"
wrote: Will be using a long wire strung around inside of the house for now when I get my tabletop. Where the radio will be there are no pipes etc, what is the best way to ground, can I use the center screw of the electric outlet. Been using protables now & a set top with a whip built in antenna (RS394). You probably won't hear any differently with a ground. And be careful where you attach one: I know a ham who lost his whole station -- lightning hit and came up through the ground wire and fried his equipment. Unless you can hear a difference, I wouldn't bother. Bob k5qwg |
Grounding
I guess the old way of attaching a wire to the screw that holds the face
plate of the electric outlet won't be any good then. I could have swore my father years ago used that for grounding. "David" wrote in message ... On Thu, 08 Dec 2005 15:44:30 GMT, "Steve Rabinowitz" wrote: Is there any where in the house or must I attch to a metal stake in the ground. Would rather not run the wire outside, "David" wrote in message . .. On Thu, 08 Dec 2005 13:02:01 GMT, "Steve Rabinowitz" wrote: Will be using a long wire strung around inside of the house for now when I get my tabletop. Where the radio will be there are no pipes etc, what is the best way to ground, can I use the center screw of the electric outlet. Been using protables now & a set top with a whip built in antenna (RS394). Only if your mains wiring is in metallic pipe or raceways. Otherwise I'd run a discrete wire. A fuse or breaker box that is ''served'' by metal conduit or raceway, or a metal (for sure) cold water pipe that has metallic continuity (for sure) into the ground. |
Grounding
Protecting the antenna means providing lightning with an
alternative path to earth. Your building does that just fine. But be better advised to earth using a lightning rod located above the roof. Safety ground system and earthing system share many components. Different systems for different purposes with some common parts. AC wall receptacle is not an earth ground. An antenna is earthed so that lightning will not take a more destructive path via the receiver. Ac receptacle ground means lightning would spread out inside the building to damage other electronics. Connect things to the wall receptacle grounded screw to protect human life. This is not same as earthing lightning. To earth lightning, install Ben Franklin's well proven solution above the roof. Earth incoming transients on utility wires using either 'whole house' protector or a ground block - all connected to a common earth ground that remains outside the building. Steve Rabinowitz wrote: I guess the old way of attaching a wire to the screw that holds the face plate of the electric outlet won't be any good then. I could have swore my father years ago used that for grounding. |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
BpnJ,
If the Loop were free standing in open Air; then yes what you say would be generally true. However, the Wire Antenna Element is usually laying against the surface of the House's Interior Walls and therefore may not be as theoretical as expected. TIP - Try the Loop Antenna with both Antenna Inputs the LO-Z 50 Ohms and the HI-Z 500 Ohms on Several Shortwave Bands : 120M - 90M - 75M - 60M - 49M - 41M - 31M - 25M - 22M - 19M - 16M - 13M - 11M YMMV - On some the LO-Z may be the best connection and on others the HI-Z may be the best connection. BALUN - As you stated a simple Matching Transformer may provide the necessary Broad Banded 'match' to be able to use a single In-Door Loop Antenna Input for All Bands. TWIN LEAD DOUBLE LOOP - Another 'Trick' is to make the Loop a Double Loop using 300 Ohm TV type Twin Lead wired in Series with a piece of the same 300 Ohm TV type Twin Lead from the Ceiling Loop to the Radio/Receiver. In this instance the HI-Z 500 Ohm Terminals usually work the best and it goes without saying that the Double Loop is Twice as Long as a Single Loop :o) This does not seem to work as well with the narrower and closer together common Speaker Wire. FWIW - Some Claim that the Double Ceiling Loop Antenna provides more signal and less noise then a Single Ceiling Loop Antenna. I have yet to do a side-by-side of the One or the Two around the same Ceiling at the same time. Note - I would thing that it would take at least 6" or may be closer to a Foot between the Single and Double Loops to give each one a reasonable independent test in the same room. Some Food-for-Thought and an Invitation to Experiment with In-Door Horizontal [Flat] Ceiling Loop Antennas. [ Surprise Yourself :] iane ~ RHF |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
Sanjaya,
Wire Wire Everywhere . . . Pick a Wire - Any Wire ! Ninty Feet (90-Ft.) of 22 AWG Stranded Hook-Up Wire RadioShack Catalog # 278-1218 http://www.radioshack.com/product/in...ductId=2036275 Fifty-Five Feet (55-Ft.) of 18 AWG Stranded Hook-Up Wire RadioShack Catalog # 278-1220 http://www.radioshack.com/product/in...ductId=2049741 Fifty-Five Feet (55-Ft.) of 18 AWG Stranded Hook-Up Wire RadioShack Catalog # 278-1220 http://www.radioshack.com/product/in...ductId=2049741 Fifty Feet (50-Ft.) of 24 AWG Clear Insulation Stranded Speaker Wire RadioShack Catalog # 278-1301 http://www.radioshack.com/product/in...ductId=2102499 [ For That "Instant" Dipole Antenna ] - In-Door In-the-Attic In-the-Room - For that "No-See-Um" [Hidden] Ceiling Loop Antenna . . . http://groups.google.com/group/rec.r...a4ff8558eb78c8 Fifty Feet (50-Ft.) of White 30 AWG Single Strand Kynar Insulated Wire Wraping Wire RadioShack Catalog # 278-502 http://www.radioshack.com/product/in...ductId=2062641 |
Grounding
I'm with Tom...
One should NEVER use the metal screw or electrical conduit for an earth ground. Not only is this contrary to the NEC code but it allows ground loop currents to exist along the single ground path due to inconsistent bonding between conduit, flanges, flange screws and...eventually...the ground rod. Lightning will follow the path of least resistance. You will often see a coil (even a single turn) of taped of professional communications atenna systems at the point of entry into the building. This is to provide, however slight, a small impedance to discourage lightning current from taking THAT path and, instead chosing a separate direct ground path. Do this little experiment: Install a good ground at the entry to your house and run a wire to it for your shortwave receiver. Once done, take an ohmmeter and measure the resistance between that ground wire and the screw on your wall outlet. I have often been surprised at how much resistance exists between the wall outlet and a "real ground." Well, that resistance is probably more than enough to divert a lightning current to a shorter path to your receiver such as through its antenna. Good luck. Vern Weiss W9STB "w_tom" wrote in message ... Protecting the antenna means providing lightning with an alternative path to earth. Your building does that just fine. But be better advised to earth using a lightning rod located above the roof. Safety ground system and earthing system share many components. Different systems for different purposes with some common parts. AC wall receptacle is not an earth ground. An antenna is earthed so that lightning will not take a more destructive path via the receiver. Ac receptacle ground means lightning would spread out inside the building to damage other electronics. Connect things to the wall receptacle grounded screw to protect human life. This is not same as earthing lightning. To earth lightning, install Ben Franklin's well proven solution above the roof. Earth incoming transients on utility wires using either 'whole house' protector or a ground block - all connected to a common earth ground that remains outside the building. Steve Rabinowitz wrote: I guess the old way of attaching a wire to the screw that holds the face plate of the electric outlet won't be any good then. I could have swore my father years ago used that for grounding. |
Quest: Connect End Of Loop To Beginning ?: In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
Hi,
Question re the "loop" Would you connect the end of the loop to the beginning, thus making a "true loop" up there, or just leave it open at the end ? Why ? What is the effect of the vertical run down to the receiver ? Would you suggest coax for this vertical section, or usually not necessary ? Bob -------------------------- "RHF" wrote in message oups.com... SR, Vice using the questionable the Ground {Green Wire} of your Household AC Power System. Why not consider a simple Around-the-Room {Ceiling Level} Horizontal [Flat] Loop Antenna. The Loop Antenna is consider a 'blanced' Antenna that does not require a Ground and is Horizontally Polarized so it generally pick-up less man made noise. The "In-Door" Horizontal [Flat] Loop Antenna is easy to build; usually is relatively long 40-60 Feet for an In-Door Antenna; and relatively lower noise pick-up to an in-door vertical antenna or long wire antenna. The Radio or Receiver can be run off of AC with an AC Ground connection via the AC Power Plug or DC without any Ground connection at all. something to consider - iane ~ RHF . . . . . |
Quest: Connect End Of Loop To Beginning ?: In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
Robert 11,
THE LOOP ANTENNA ELEMENT : The Loop being a Square/Rectangular Shaped Loop completes the Circling of the Room around the Four Walls. Both Ends of the Loop come together at some point on the Wall or at a Corner of the Walls near the Ceiling and are connected to a Pair {Two} Parallel Wire Feed-in-Line that goes down to the Radio's Antenna Input. THE FEED-IN-LINE : The short vertical Feed-in-Line for this type of In-Door {In-the-Room} Loop Antenna is usually a Pair {Two} Parallel Wires. * 300 Ohm TV type Twin Lead works well as a Feed-in-Line for this type of Loop Antenna. * Speaker Wire also can be used; either flat or twisted will work. * The basic wire used to make the Wire Loop Antenna Element can be continued as a single piece from the Radio up the Wall; around the Four Walls; and down back to the Radio. If this is done then it is recommended that the short vertical parallel run has the two Wires Twisted together. * A piece of Audio Coax Cable can also be used; especially if the Radio uses an 1/8" Mono Jack for the External Antenna Input. WANT A BIGGER LOOP ANTENNA - PUT IT IN THE ATTIC : [ When an Out-Side / Out-Doors Antenna is NOT Permitted. ] KISAP: I recommend using TV type Antenna Parts for most "In-the-Attic" Antenna installations. * 75 Ohm Coax Cable for the Feed-in-Line for Household 'man-made' Noise RFI/EMF Reduction. * TV 75 Ohm to 300 Ohm Matching Transformer (Balun) for Noise RFI/EMF Reduction and AM/MW Band Signal Reduction. * TV 300 Ohm Twin Lead for the Wire Antenna Element 50-100 Feet -or- 90 Feet of Insulated Hook-Up Wire. * "F" Jack to 1/8" Plug (1/8" Mono-Jack Adapter) RadioShack Catalog # 278-257 READ - For Shortwave Listening (SWL) here is a "Simpler" Horizontal Loop Antenna in the Attic using common TV type Parts. http://groups.yahoo.com/group/Shortw...a/message/6656 http://groups.google.com/group/rec.r...59a36c32f5ecd7 READ - Shortwave Listeners (SWL) Horizontal Loop Antenna built with common and cheap TV Parts http://groups.yahoo.com/group/Shortw...a/message/6135 http://groups.google.com/group/rec.r...8323867b8b44a3 ADDITIONAL READING LIST - Here are several Messages to Read about In-the-Attic Antennas: * Things-to-Think-about: Using Attic Antenna with the your 'portable' AM/FM/Shortwave Radio. http://groups.yahoo.com/group/Shortw...a/message/1658 * A Compilation of "In-the-ATTIC" Antennas http://groups.yahoo.com/group/Shortw...na/message/426 * Low Cost SWL Antenna (Made From TV Parts) http://groups.yahoo.com/group/Shortw...nna/message/17 * ATTIC - Receiving Antenna Question - Think Loop made from TV Parts http://groups.yahoo.com/group/Shortw...a/message/1635 * Ground Required At Balun ? {Getting "Grounded" in your Attic} http://groups.yahoo.com/group/Shortw...na/message/287 * Snake-in-the-Attic SWL Antenna {Simplest Low Noise Attic Antenna} http://groups.yahoo.com/group/Shortw...na/message/313 http://groups.yahoo.com/group/Shortw...na/message/317 * AM/MW Band Signal Reduction using TV Type Coax Cable Parts for better Shortwave Listener Antenna http://groups.yahoo.com/group/Shortw...na/message/930 * Simple SW Antenna = Improved Random Wire Antenna using TV Antenna Parts http://groups.yahoo.com/group/Shortw...na/message/740 .. .. hope this helps - iane ~ RHF |
Grounding
Vern Weiss [W9STB],
Do the same simple experiment in a 50+ Year Old House and you may be 'shocked' at the results ;-) ~ RHF |
Grounding
In article ,
"Smokey" wrote: I'm with Tom... Snip Then you would be the "thunder" to the nut case lightning Troll. In any event into the kill file with you. Plonk -- Telamon Ventura, California |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
In article . com,
"RHF" wrote: M... - " The loop will be unbalanced if you don't use a balun. " Please Educate me as to Why the Loop Antenna would be Un-Balance without using a Balun ? i want to know - cause -iane ~ RHF Any time you connect a transmission line directly to a antenna the coax shield can affect the antenna unless you decouple it. You can: 1. Run the coax at a right angle from the antenna elements. 2. Use a choke of some type on the coax. Otherwise the coax shield become part of the antenna. -- Telamon Ventura, California |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
M...,
My assumtions were that he said he was getting ready for a Table Top Receiver; and that it would have both a LO-Z 50 Ohm {SO-239 Jack} and HI-Z 500 Ohm {Pair of Terminals} as the External Antenna Inputs. But in re-reading the original post; I see that it is a RadioShack DX-394 which only has the one SO-239 Jack as it's External Antenna Input. My general preference with a Ceiling Loop Antenna is to use 300 Ohm Twin Lead as the Feed-in-Line from the Wire Loop Element to the Receiver's HI-Z 500 Ohm {Pair of Terminals} for the External Antenna Input. The exception being if the Radio uses an 1/8" Mono-Jack as the External Antenna Input. Then a short piece of simple Audio Coax Cable with an 1/8" Mono-Plug can be the better choice for a Feed-in-Line from the Loop Antenna to the Radio. Note - Horizontal Wire Loop Antenna Element directly connected to a Vertical Feed-in-Line. iane ~ RHF |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
In article .com,
"RHF" wrote: M..., My assumtions were that he said he was getting ready for a Table Top Receiver; and that it would have both a LO-Z 50 Ohm {SO-239 Jack} and HI-Z 500 Ohm {Pair of Terminals} as the External Antenna Inputs. But in re-reading the original post; I see that it is a RadioShack DX-394 which only has the one SO-239 Jack as it's External Antenna Input. My general preference with a Ceiling Loop Antenna is to use 300 Ohm Twin Lead as the Feed-in-Line from the Wire Loop Element to the Receiver's HI-Z 500 Ohm {Pair of Terminals} for the External Antenna Input. The exception being if the Radio uses an 1/8" Mono-Jack as the External Antenna Input. Then a short piece of simple Audio Coax Cable with an 1/8" Mono-Plug can be the better choice for a Feed-in-Line from the Loop Antenna to the Radio. Note - Horizontal Wire Loop Antenna Element directly connected to a Vertical Feed-in-Line. You would be better off using 50 ohm coax for the loop antenna and also the lead-in using the radios low Z input. If you are in a low noise area then use an unbalanced coax loop for more pickup. If local noise is a problem then use a voltage balanced loop. -- Telamon Ventura, California |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
I agree on the choke, but it seems to me the right angle coax would be
an antenna, but not aimed with the rest of the loop. For instance, a horizontal loop connected to vertical coax would fit your description, but I would still say the coax unbalanced the loop. FWIW, I get better results with vertical loops than horizontal. Telamon wrote: In article . com, "RHF" wrote: M... - " The loop will be unbalanced if you don't use a balun. " Please Educate me as to Why the Loop Antenna would be Un-Balance without using a Balun ? i want to know - cause -iane ~ RHF Any time you connect a transmission line directly to a antenna the coax shield can affect the antenna unless you decouple it. You can: 1. Run the coax at a right angle from the antenna elements. 2. Use a choke of some type on the coax. Otherwise the coax shield become part of the antenna. -- Telamon Ventura, California |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
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In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
In article .com,
"RHF" wrote: Telamon, Yes - A 'smaller' Vertical Coax Cable Loop Antenna is another opinion to consider for an In-Door Antenna. The "TRICK" to TV 'type' Coax Cable [Shielded] SWL Loop Antennas {RHF} http://groups.yahoo.com/group/Shortw...a/message/1626 http://groups.google.com/group/rec.r...a0aadd03af7bc7 Yes the 75 ohm TV stuff will work OK if that is what you have around. The only problem there is the cable size does not match up with the 50 ohm connectors. Usually you can hack that well enough to connect things together. If you are going to buy the coax you might as well but the 50 ohm cable. -- Telamon Ventura, California |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
Telamon,
Thank You for remind me of this simple fact about a properly Terminated Coax Cable and the need to have it Matched on both ends. [ Making It an Effective Signal Conduit. ] to live is to learn - cause - iane ~ RHF |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
Telamon,
FWIW - Most of my better performing "GreerTech" Coax Cable Veritcal Loop Antennas are made using full size RG8 Coax Cable. Yes - Sometimes Bigger (Thicker) is Better. The basic design of the "GreerTech" Coax Cable [Shielded] Loop Antenna is good and very practical. GREERTECH = http://www.greertech.com/hfloop/mymagloop.html LOOP= http://www.greertech.com/hfloop/mymagloop.html http://groups.yahoo.com/group/Shortw...a/message/1625 http://groups.yahoo.com/group/Shortw...a/message/1730 http://groups.yahoo.com/group/Shortw...a/message/1539 http://groups.yahoo.com/group/Shortw...a/message/1008 http://groups.google.com/group/rec.r...8005ce8c7f5c9c ~ RHF |
In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
"bpnjensen" wrote the impedance for this type of antenna is about 100 ohms. At what frequency? A large horizontal loop of about 40 feet or larger circumference will exhibit different impedance across the bands as will any single wire antenna or dipole. Except that a large horizontal loop will exhibit a significantly less impedence variation. would suggest that, if this type of antenna is used, for best match it be mated to the low-Z input of the radio (50 ohms rather than 500), although an appropriate transformer could easily resolve this (probably minor) problem regardless of the input. I wouldn't be too concerned about the impedance for receiving purposes. The broadband nature of a large horizontal loop will offset any loss from impedance mismatch compared to any other type of single wire antenna or dipole at the same height. As a once famous person said, "It's all relative." Or better, "If you build it 'RF' will come." Just do it and experiment. |
To RHF Again: Quest: Connect End Of Loop To Beginning ?: In-Door Horizontal [Flat] Loop Antenna - - - No Grounding Required
"Robert11" wrote a. Would coax work (meaningfully) better than the 300 ohm TV wire for the feed line ? Would I need a Balun also ? Using 300 ohm line gently twisted (don't kink it) in a spiral (any direction - L or R) once about every 12-18 inches or so is generally a better "match" than coax for the broadband large horizontal loop. b. What are the major performance differences, therefore, between the apparently 3 different ways of doing it: - your suggestion of a balanced twin line to receiver Don't be concerned about impedence mismatch using a large horizontal loop for reception purposes. It is superior to any other single wire antenna or dipole. The large horizontal loop will perform equally to your random wire on your random wires resonant frequency or multiple but will out perform it over all other bands. Assuming they are compared at the same height. My horizontal loop is about 80 meters in circumference in the shape of a fat "L" using a 450ohm ladderline feed. It is about 15 meters in height - not ideal, but so what. I can transmit on any HF amateur frequency without using any balun or matching device. Reception exhibits the same characteristics, as it should. - what I now have, a single wire forming a sort of loop, with the end open This is a random wire regardless of the configuration. It is NOT a loop. Creating a loop would make it far more "broadbanded" than a random wire or dipole. Just try it and experiment. |
The In-the-Attic Horizontal [Flat] Loop Antenna - Just may be the better choice to fill the available space.
Conclusion - Having stated the three above sets of parameters
for the above three types / shapes of Antennas that are often used as In-the-Attic Antenna : It now becomes apparent to me that the Loop Antenna is the better choice with a potential for : * Higher Signal Levels due to the fact for the available space there is simply more Wire in the Air....................................... This can vary though. Would depend on the bands used, etc.. Just having more wire in the air doesn't mean much in itself. It's quite possible and common for a smaller footprint antenna to trounce the larger one. IE: my coax fed dipoles have a total of 440 ft of wire in the air. Yes, it works well on any HF band, but my yagi would eat it for lunch on the bands the yagi is designed for. And the yagi uses a total of appx 90 ft of element/s to do it. * Equally as low Noise due to the natural properties of a Loop. And what would these properties be? The only "noise" property a loop has that differs from any other wire antenna is the reduction of corona, or static buildup, etc. And only in locations where that could help, would it be any advantage. Here in Houston, it would mean nada. At HCJB, with the large amounts of element eating corona up in those high mountains, it can help. Other than that, the loops behave no different than any other antenna. * Greater Antenna Aperture {Signal Capture Area} due to the natural shape and size of a Loop in any given space; with less apparent signal fading. This means little in general.. I can run a full wave loop on 80m for NVIS, and compare it to a dipole, and they are almost exactly the same in the real world. If you model a 80 dipole at 40 ft and compare it with a 80 horizontal loop at 40 ft, the loop has the small advantage of 1 db. In the real world, this is basically unnoticable on HF. It's not the aperture you would want to worry about. It would be the pattern of the antenna on the various bands, vs whatever you would compare it to. This can easily be modeled. Going One Step Farther : A Vertical [Tall] Loop Antenna In-the-Attic could offer almost as many advantages over the Random Wire Antenna and Dipole Antenna; as does the Horizontal [Flat] Loop Antenna. You say? What would these advantages be? Have you tried modeling it? You might be surprised... A full wave loop has no advantage over a dipole, except in differences in pattern. They are both about equally efficient. What would that mean? On some bands, the dipole could be better. On others, the loop... Basically, it's a crap shoot. Here, I have enough room to run either full wave loops, or dipoles. I run the dipoles. Why? Same appx performance, with less work involved. On the higher bands, I'd generally prefer the dipoles, vs a horizontal loop due to current distribution concerns. Vertical loop vs dipole? About 2 db or so, and barely worth the trouble. I'd rather run an extended double zepp, vs the vertical fed loop. Has about 1 db more gain on it's design freq. Intuitively I would think that for a Vertical Loop Antenna to perform up to its potential the maximum Length-to-Height (Aspect) Ratio would be about 4:1 or 5:1 . Nope. The maximum performing loop is a perfect circle. A square would be better than a tall narrow loop. Whatever covers the largest area is best as far as gain. If you want horizontal, you feed at the top or bottom. Vertical, from either side.. A loop is a loop no matter the orientation. Same properties will apply to both. Anyway, there is no real advantage to a loop vs dipole, unless the pattern of the loop is more favorable for a certain band and direction, etc, in use at the time. This will vary. As far as s/n ratio, you could run either one with little or no difference on most the bands, assuming both are properly decoupled from the feedline.. MK |
The In-the-Attic Horizontal [Flat] Loop Antenna - Just may be the better choice to fill the available space.
MK - By Definition "In-the-Attic"
In-the-Attic = Limited Space and Antenna Size In-the-Attic = Usually means that the Wire Antenna Element is 12 Feet to 18 Feet High above AGL for a single story house. Maybe twice that for a two story house or split-level condo. NOTE - For a Shortwave Listener's (SWL) "Receive Only" Antenna that is designed to "Fill" the Available Space : Whether these Antennas are : a Random Wire; a Dipole, or a Loop they are not "Cut' for any specific Wave Length and Frequency; they are simply Random Wire Antennas IN-THE-ATTIC AND ATTIC SIZE : In a 30 Foot by 40 Foot size Attic a basic straight Random Wire Antenna can be 30 Feet along the short side; 40 Feet along a the long side; or 50 Feet across a the diagonal. In a 30 Foot by 40 Foot size Attic a simple straight Wire Dipole Antenna can be 30 Feet along the short side; 40 Feet along a the long side; or 50 Feet across a the diagonal. In a 30 Foot by 40 Foot size Attic a common Wire Loop Antenna would be : 30 Feet along one short side; 40 Feet along one the long side; 30 Feet along the other short side; 40 Feet along the other long side; for a total of 140 Feet around the Attic [.] MK - It should be self-evident that " there is simply more Wire in the Air. " and that is all I said and meant to say. RELATIVE ANTENNA NOISE : " Equally as low Noise due to the natural properties of a Loop. " The usual ascertion is that a Dipole Antenna has a Lower Noise Factor (Property) then the same Length Random Wire at the same Height; all other things being equal : Balun / No Balun; Coax Cable / Twin Lead / Ladder Line; ETC. The Horizontal [Flat] Loop Antenna has the same Lower Noise Factor (Property) then the Dipole Antenna has in the same relative Available "In-the-Attic" Space : All other things being equal : Balun / No Balun; Coax Cable / Twin Lead / Ladder Line; ETC. There is Nothing to be gained or lost by using the Dipole or Loop Antenna in the Attic Noise Wise : But with the Loop Antenna more Wire is in the Air which can result in more Signal from the Antenna. ANTENNA APERTURE : RHF Said - " Greater Antenna Aperture {Signal Capture Area} due to the natural shape and size of a Loop in any given space; with less apparent signal fading. " MK - You model two 80 Meter Band Antennas; a Half-Wave Dipole Antenna and a Full-Wave Horizontal Loop Antenna and say that they are the same with little measurable difference between the two. "OK" Again here my beginning point is "In-the-Attic" were both the Dipole Antenna and the Horizontal [Flat] Loop Antenna are using the same Available Space and are in fact simply two 'random wire' antennas that happen to be laid-out in the confines of the Attic. Here the 50 Foot long Dipole Antenna with lets say 50 Square Foot of Signal Capture Area has less potential as an Antenna : Then the 140 Foot long Horizontal [Flat] Loop Antenna with lets say 120 Square Foot of Signal Capture Area that has more potential as an Antenna. To my simple way of thinking relative size and area does matter. ? Now is this Theoretically or Machine Measurable - Most Likely. ? Now is this Discernable by the Shortwave Listener (SWL) - Maybe. THE CRAP SHOOT : MK you say : "Basically, it's a crap shoot." "I run the dipoles." RHF says : For an In-the-Attic Antenna "Crap Shoot" I prefer the Horizontal [Flat] Loop Antenna - It's a matter of choice. MY INTUITIVE STATEMENT ABOUT VERTICAL LOOP ANTENNAS : RHF Said - " Intuitively I would think that for a Vertical Loop Antenna to perform up to its potential the maximum Length-to-Height (Aspect) Ratio would be about 4:1 or 5:1 ." Again here my beginning point is "In-the-Attic" most every Attics that I have been in is Longer and Wider then they are High {Tall}. So 'if' we are trying to Maximizing the Size of the Vertical Loop Antenna then a simple Circle or Square would not produce as much Wire Length and Combined Area as a Rectangle or Triangle using up the Available Space inside the Attic. The added comment about the Length-to-Height (Aspect) Ratio being about 4:1 or 5:1 was to not have the Vertical Loop become to flat compressed and effectively become a fat Folded Dipole Antenna of sorts. RESTATING MY CONCLUSIONS {NON-TECHNICAL OPINIONS} : For a "Receiver Only" Antenna being used by a Shortwave Listener (SWL) The Horizontal [Flat] Loop Antenna used In-the-Attic may/could/should perform better then the simple Dipole Antenna with potentially Higher Signal Levels; the same relative Noise Level; and less apparent Fading. STAYING ON MESSAGE - THIS CONVERSATION : MK - You appear to be a "Technical Person" and that is well and good. However, I am for the most part a non-technical person who simply tries to Keep It Simple And Practical [KISAP]. For me these Conversations can be an interesting exercise in restating my simple minded opinions : But for you these Conversations may turn out to be an exercise in futility - a Fools Errant so to speak. MK - Part of my 'iane' signature { I Ain't No Elmer } Means : I Don't Get Techincal - Because - I simply am not smart enough to try and WOW anyone with the all that math or science. MK - I Am Glad We Had This Talk :o) kisap - keeping it simple and practical ~ iane ~ RHF |
The In-the-Attic Horizontal [Flat] Loop Antenna - Just may be the better choice to fill the available space.
One thing you have to remember about the arguments between various antenna
types; dipoles, longwires, yagi's. etc. These are all "tuned" antennas (even a random longwire) and their maximum gain is only evident in a single band. While a large horizontal loop of "one wave" in length (example: 80 meters circumference = one wavelength at 3.5MHz) will perform equally to a "half wave" dipole (i.e. 40 meters long) AT THE SAME HEIGHT. Where the large horizontal loop shines is at all frequencies about its "one wave" length. The large horizontal loop of a theoretical length of 80 meters in circumference will exhibit the characteristics of a dipole at ANY frequency above 3.5MHz. Whereas a halfwave dipole will only exhibit equal performance at 3.5MHz and its multiples (i.e. 7MHz, 14MHz, 21MHz). Everywhere else the dipole will exhibit a loss compared to a large horizontal loop. The characteristics of our theoretical 80 meter large horizontal loop are "relatively" flat all through the spectrum with much less peaks or valleys compared to a dipole all the way up to at least 30MHz. It is the ideal antenna for general SWL and HF utility monitoring because its performance is equal all across the shortwave spectrum. Consider its performance similar to a UHF/VHF discone antenna. It exhibits a flat response, no gain or loss (relative to a half-wave vertical), from 50-900MHz! That is about 1000MHz! - that is very "broadbanded." "RHF" wrote in message ups.com... MK - By Definition "In-the-Attic" In-the-Attic = Limited Space and Antenna Size In-the-Attic = Usually means that the Wire Antenna Element is 12 Feet to 18 Feet High above AGL for a single story house. Maybe twice that for a two story house or split-level condo. NOTE - For a Shortwave Listener's (SWL) "Receive Only" Antenna that is designed to "Fill" the Available Space : Whether these Antennas are : a Random Wire; a Dipole, or a Loop they are not "Cut' for any specific Wave Length and Frequency; they are simply Random Wire Antennas IN-THE-ATTIC AND ATTIC SIZE : In a 30 Foot by 40 Foot size Attic a basic straight Random Wire Antenna can be 30 Feet along the short side; 40 Feet along a the long side; or 50 Feet across a the diagonal. In a 30 Foot by 40 Foot size Attic a simple straight Wire Dipole Antenna can be 30 Feet along the short side; 40 Feet along a the long side; or 50 Feet across a the diagonal. In a 30 Foot by 40 Foot size Attic a common Wire Loop Antenna would be : 30 Feet along one short side; 40 Feet along one the long side; 30 Feet along the other short side; 40 Feet along the other long side; for a total of 140 Feet around the Attic [.] MK - It should be self-evident that " there is simply more Wire in the Air. " and that is all I said and meant to say. RELATIVE ANTENNA NOISE : " Equally as low Noise due to the natural properties of a Loop. " The usual ascertion is that a Dipole Antenna has a Lower Noise Factor (Property) then the same Length Random Wire at the same Height; all other things being equal : Balun / No Balun; Coax Cable / Twin Lead / Ladder Line; ETC. The Horizontal [Flat] Loop Antenna has the same Lower Noise Factor (Property) then the Dipole Antenna has in the same relative Available "In-the-Attic" Space : All other things being equal : Balun / No Balun; Coax Cable / Twin Lead / Ladder Line; ETC. There is Nothing to be gained or lost by using the Dipole or Loop Antenna in the Attic Noise Wise : But with the Loop Antenna more Wire is in the Air which can result in more Signal from the Antenna. ANTENNA APERTURE : RHF Said - " Greater Antenna Aperture {Signal Capture Area} due to the natural shape and size of a Loop in any given space; with less apparent signal fading. " MK - You model two 80 Meter Band Antennas; a Half-Wave Dipole Antenna and a Full-Wave Horizontal Loop Antenna and say that they are the same with little measurable difference between the two. "OK" Again here my beginning point is "In-the-Attic" were both the Dipole Antenna and the Horizontal [Flat] Loop Antenna are using the same Available Space and are in fact simply two 'random wire' antennas that happen to be laid-out in the confines of the Attic. Here the 50 Foot long Dipole Antenna with lets say 50 Square Foot of Signal Capture Area has less potential as an Antenna : Then the 140 Foot long Horizontal [Flat] Loop Antenna with lets say 120 Square Foot of Signal Capture Area that has more potential as an Antenna. To my simple way of thinking relative size and area does matter. ? Now is this Theoretically or Machine Measurable - Most Likely. ? Now is this Discernable by the Shortwave Listener (SWL) - Maybe. THE CRAP SHOOT : MK you say : "Basically, it's a crap shoot." "I run the dipoles." RHF says : For an In-the-Attic Antenna "Crap Shoot" I prefer the Horizontal [Flat] Loop Antenna - It's a matter of choice. MY INTUITIVE STATEMENT ABOUT VERTICAL LOOP ANTENNAS : RHF Said - " Intuitively I would think that for a Vertical Loop Antenna to perform up to its potential the maximum Length-to-Height (Aspect) Ratio would be about 4:1 or 5:1 ." Again here my beginning point is "In-the-Attic" most every Attics that I have been in is Longer and Wider then they are High {Tall}. So 'if' we are trying to Maximizing the Size of the Vertical Loop Antenna then a simple Circle or Square would not produce as much Wire Length and Combined Area as a Rectangle or Triangle using up the Available Space inside the Attic. The added comment about the Length-to-Height (Aspect) Ratio being about 4:1 or 5:1 was to not have the Vertical Loop become to flat compressed and effectively become a fat Folded Dipole Antenna of sorts. RESTATING MY CONCLUSIONS {NON-TECHNICAL OPINIONS} : For a "Receiver Only" Antenna being used by a Shortwave Listener (SWL) The Horizontal [Flat] Loop Antenna used In-the-Attic may/could/should perform better then the simple Dipole Antenna with potentially Higher Signal Levels; the same relative Noise Level; and less apparent Fading. STAYING ON MESSAGE - THIS CONVERSATION : MK - You appear to be a "Technical Person" and that is well and good. However, I am for the most part a non-technical person who simply tries to Keep It Simple And Practical [KISAP]. For me these Conversations can be an interesting exercise in restating my simple minded opinions : But for you these Conversations may turn out to be an exercise in futility - a Fools Errant so to speak. MK - Part of my 'iane' signature { I Ain't No Elmer } Means : I Don't Get Techincal - Because - I simply am not smart enough to try and WOW anyone with the all that math or science. MK - I Am Glad We Had This Talk :o) kisap - keeping it simple and practical ~ iane ~ RHF . All are WELCOME and "Invited to Join" the Shortwave Listener (SWL) Antenna eGroup on YAHOO ! http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ SWL ANTENNAS GROUP = http://tinyurl.com/an6tw . Some Say: On A Clear Day You Can See Forever. I Believe : On A Clear Night You Can Hear Forever . . . and Beyond , , , The BEYOND ! ! ! With a Shortwave Listening Antenna of your own making. "If You Build It {SWL Antenna} You Will Hear Them !" http://groups.yahoo.com/group/Shortwave-SWL-Antenna/ SWL ANTENNAS GROUP = http://tinyurl.com/an6tw . . . . . |
The In-the-Attic Horizontal [Flat] Loop Antenna - Just may be the better choice to fill the available space.
SED,
Thank You for the Reply and Sharing this Info concerning the characteristics of the Dipole Antenna verses the Loop Antenna. May we all Learn something new each day; and re-learn something anew all over again everyday :o) - iane ~ RHF |
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