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Antenna design
Hi there, I am trying to build a longwire antenna for use in the 20 meter
band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre |
A google search of "dipole antenna" gave about 48k hits.
I think the following url will be of help: http://www.angelfire.com/mb/amandx/dipole.html The Alpha-Delta Sloper will give you very good wide band coverage. It can be seen at http://www.universal-radio.com/catalog/sw_ant/3377.html ========= Pierre Vachon wrote: Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre |
Hi Pier
- Try getting a portable SWR & walking around your lot, putting it to a " Blank " frequency and checking where you hear noise, and where you don't You should also check to see swhere on your lot you pick up 20 - 70 meter frequencies your interested in Try this both in the daytime, and at night.. THEN You'll be able to put an antenna in the ": Noise Free areas" Dan / NYC ( Sangean 606A, Jwin M14, Icom R-75 ) In article , "Pierre Vachon" writes: Subject: Antenna design From: "Pierre Vachon" Date: Mon, 11 Oct 2004 18:58:03 -0400 Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre |
Pierre,
Unless you have a transformer nearby, the powerlines won't necessarily be the cause of the hum you mention. They can certainly cause noise, when something is loose or dirty. But not usually a hum. Use a portable SW radio to track it down. Walk around with it to see if the hum gets louder or softer. Mark. "Pierre Vachon" wrote in message . .. Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre |
"Pierre Vachon" wrote Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre The minimum height above ground is about 1 millimeter ;-) That's where Hurricane Isabel dumped one of my long wires last fall. It took over a week to clear debris away before I could get it back up in the tree it was pulled out of. It still received quite well in the meantime, even laying on the ground. Of course the higher the antenna, the better it receives. At an angle of more than 45 degrees, there is very little effect on the direction the sloping wire points. At an angle of more than about 75 degrees, you are approaching a "vertical" which is known for it's higher background noise. Not desirable in DX work. You didn't say if you are going to use a Balun transformer at the antenna and coax feedline to connect to the radio. *If* you do, then you can certainly ground the shield of the coax at the balun (even ground the unused side of the balun), and shield ground the coax again before it comes into your home. That can certainly help reduce noise. If the coax shield is not grounded, the home electrical ground can "feed" noise from the radio, out the coax shield, and back into the coax center conductor at the antenna connection. Shield grounding does prevent this from happening. It is also required in order for any static or lightning protection device to work properly, should you use those devices. Good luck, Jack |
= = = "Pierre Vachon" wrote in message
= = = ... Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre PV, Your simplest 'design' would be a "Low Noise" Antenna in the 'form' of an Inverted "L" Antenna. Since you have Power Line at the front of the Yard. Consider running your Coax Cable to the Back-End of the Yard (Possibly a Corner?). Construct an Antenna Support at this 'spot'. I like to us Top-Rail as a Free-Standing Antenna Support. Next at this back-of-the-yard 'location' install a Ground Rod. Then 'mount' a Matching Transformer on the Top of the Ground Rod. (This is your Primary Grounding Point for your Antenna and Ground System.) Connect the Antenna Wire Element and Coax Cable to the Matching Transformer (Balun/MLB). Route/Run the Antenna Wire Element 'up' to the Top of the Top Rail and 'out' toward the front yard. Near the front of the Yard find or build a second Antenna Support. (Top Rail Again?) Some people like "Exact Numbers". So since you mention the 70 Meter and 20 Meter Bands; consider 'cutting' your Inverted "L" Antenna to be a Quarter Wave Length on Top-Horizontal-Arm for your Lowest Band and a Quarter Wave Length on the Bottom-Vertical-Leg or your Lowest Band. * 80 Meter 1/4WL = 67 Feet Top-Horizontal-Arm * 20 Meter 1/4WL = 18 Feet Bottom-Vertical-Leg Total Length of the Antenna Wire Element = 85 Feet. READ: Antennas - Five Things to Consider : Antenna, Balun, Ground, Coax & Planning http://groups.yahoo.com/group/Shortw...a/message/1544 The SWL Versions of the Inverted "L" Antennas can be any size because they are in-fact simply Random Wire Antennas that are 'designed' to Fit the available space. http://groups.yahoo.com/group/Shortw...nna/message/54 Inverted "L' Antenna Reading List http://groups.yahoo.com/group/Shortw...na/message/374 'About' the Inverted "L" Antenna = http://tinyurl.com/5aw9a 'Sizing' the Inverted "L" Antenna = http://tinyurl.com/5cqf8 The 'Low Noise' Inverted "L" Antenna = http://tinyurl.com/5953c About - TOP RAIL as a "Free Standing" Antenna Support http://groups.yahoo.com/group/Shortw...na/message/201 http://groups.yahoo.com/group/Shortw...enna/message/3 .. .. REMEMBER: "The Shortwave Antenna is 55.5% of the . . . Radio/Receiver and Antenna/Ground Reception Equation" http://groups.yahoo.com/group/Shortw...na/message/288 A Shortwave Antenna is "Equally" Important for Good Reception [.] .. .. iane ~ RHF .. Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and beyond, The Beyond ! .. .. |
Pierre Vachon wrote:
Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre A real longwire antenna is much longer than what you are thinking of building. The antenna you describe is called a 'random wire' or inverted-L. This kind of antenna is not tuned for a specific band or range of frequencies. In fact, it performs well throughout the shortwave spectrum. See the following website for instructions on building a good low noise inverted-L antenna. I use this kind with my R8B. http://www.anarc.org/naswa/badx/ante...e_antenna.html ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
"starman" wrote in message ... Pierre Vachon wrote: Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre A real longwire antenna is much longer than what you are thinking of building. The antenna you describe is called a 'random wire' or inverted-L. This kind of antenna is not tuned for a specific band or range of frequencies. In fact, it performs well throughout the shortwave spectrum. See the following website for instructions on building a good low noise inverted-L antenna. I use this kind with my R8B. http://www.anarc.org/naswa/badx/ante...e_antenna.html Hmm. That brings up a question that I'd thought of earlier, but when I was writing my posts, I forgot to put it in. How do you figure out the impedance of various random wires of different gauges?? John Doty's article mentioned an 18 gauge wire hung more than a few feet above the ground, but I'm just curious what sort of differences there would be using, say, 14, 16 or 22 gauge wire in a similar scenario. I can't imagine trying to test it without a load of some sort. --Mike L. |
Michael Lawson wrote: "starman" wrote in message ... Pierre Vachon wrote: Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre A real longwire antenna is much longer than what you are thinking of building. The antenna you describe is called a 'random wire' or inverted-L. This kind of antenna is not tuned for a specific band or range of frequencies. In fact, it performs well throughout the shortwave spectrum. See the following website for instructions on building a good low noise inverted-L antenna. I use this kind with my R8B. http://www.anarc.org/naswa/badx/ante...e_antenna.html Hmm. That brings up a question that I'd thought of earlier, but when I was writing my posts, I forgot to put it in. How do you figure out the impedance of various random wires of different gauges?? John Doty's article mentioned an 18 gauge wire hung more than a few feet above the ground, but I'm just curious what sort of differences there would be using, say, 14, 16 or 22 gauge wire in a similar scenario. I can't imagine trying to test it without a load of some sort. Don't worry about it. The gauge of the wire will have an extremly minimal effect, and besides, there are so many other variables as well. dxAce Michigan USA http://www.iserv.net/~n8kdv/dxpage.htm |
In article ,
"Michael Lawson" wrote: "starman" wrote in message ... Pierre Vachon wrote: Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to groundit?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre A real longwire antenna is much longer than what you are thinking of building. The antenna you describe is called a 'random wire' or inverted-L. This kind of antenna is not tuned for a specific band or range of frequencies. In fact, it performs well throughout the shortwave spectrum. See the following website for instructions on building a good low noise inverted-L antenna. I use this kind with my R8B. http://www.anarc.org/naswa/badx/ante...e_antenna.html Hmm. That brings up a question that I'd thought of earlier, but when I was writing my posts, I forgot to put it in. How do you figure out the impedance of various random wires of different gauges?? John Doty's article mentioned an 18 gauge wire hung more than a few feet above the ground, but I'm just curious what sort of differences there would be using, say, 14, 16 or 22 gauge wire in a similar scenario. I can't imagine trying to test it without a load of some sort. A decrease in the gauge number means an increase in the wire diameter. If you increase the wire diameter the impedance goes down. If you place the wire closer to the ground the impedance goes down. The difference between a step in wire gauge is about 12 ohms. A 16 gauge wire 5 to 15 feet off the ground ranges from 500 to 600 ohms. -- Telamon Ventura, California |
Michael Lawson wrote:
"starman" wrote in message ... Pierre Vachon wrote: Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre A real longwire antenna is much longer than what you are thinking of building. The antenna you describe is called a 'random wire' or inverted-L. This kind of antenna is not tuned for a specific band or range of frequencies. In fact, it performs well throughout the shortwave spectrum. See the following website for instructions on building a good low noise inverted-L antenna. I use this kind with my R8B. http://www.anarc.org/naswa/badx/ante...e_antenna.html Hmm. That brings up a question that I'd thought of earlier, but when I was writing my posts, I forgot to put it in. How do you figure out the impedance of various random wires of different gauges?? John Doty's article mentioned an 18 gauge wire hung more than a few feet above the ground, but I'm just curious what sort of differences there would be using, say, 14, 16 or 22 gauge wire in a similar scenario. I can't imagine trying to test it without a load of some sort. --Mike L. The size (gauge) of the wire is not important for a *reception* antenna. It does matter for a transmitting antenna. The typical inverted-L has an impedance of several hundred ohms for much of it's frequency range. That's why a 9:1 (impedance) balun is often used. If the receiver has an antenna input impedance of about 50-ohms, a 9:1 balun will match it to a 450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is actually 3:1. My balun has a primary winding with 10-turns and a secondary with 30-turns. I used #22 enameled wire on a 1/2" dia. type-43 ferrite core. I plan to make a new balun using a 'binocular' core. This core shape makes the balun's impedance more consistent throughout it's frequency range. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
(RHF) wrote in message om...
= = = "Pierre Vachon" wrote in message = = = ... Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? A year or so ago I had to come up with a replacement for an ageing vertical antenna for my amateur radio station...After researching, I decided to put up a full wave loop cut for 80 meters..Im going to quote some sentences from this article, which you should check out: http://www.bloomington.in.us/~wh2t/loop.html "To determine the approximate length in feet of a Full Wave Loop antenna use the formula 1005/Freq in Mhz = length in feet. For 160 meters a full wave loop antenna resonant at 1.9 Mhz would be about 529 feet long. For the 75 meter band a full wave loop antenna resonant at 3.85 would be about 261 feet long. A full wave for 3.9 Mhz = 257 Feet 8 inches. " I happened to design mine for the 75/80 meter band. "This type of antenna doesn't depend on an efficient ground system for efficient performance. The impedance of a Full Wave Loop antenna is theoretically in the vicinity of 100 ohms. Connect one end of the wire to the coax center and Connect the coax shield to the other end of the wire. Be sure and seal the end of the coax against water. Form the wire in a loop and run it horizontally to trees or whatever supports are handy. Be sure to insulate the wire from the supports. " Now, this antenna works great on receive and transmit on everything from 75/80 meters and up (10-80) for transmit, the meager automatic antenna tunner in me bloody kenwood ts450sat tunes it..amazing..and the one band that sometimes gives me a bit of trouble is 15 meters, where I have to use the external tuner.. And it hears really good everywhere my radio will go (general coverage)...mine is only up an average of about 20 ft.. So, if you have the room I'd seriously consider a full wave loop..good luck.. Steve kb8viv |
"starman" wrote in message ... Michael Lawson wrote: "starman" wrote in message ... Pierre Vachon wrote: Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre A real longwire antenna is much longer than what you are thinking of building. The antenna you describe is called a 'random wire' or inverted-L. This kind of antenna is not tuned for a specific band or range of frequencies. In fact, it performs well throughout the shortwave spectrum. See the following website for instructions on building a good low noise inverted-L antenna. I use this kind with my R8B. http://www.anarc.org/naswa/badx/ante...e_antenna.html Hmm. That brings up a question that I'd thought of earlier, but when I was writing my posts, I forgot to put it in. How do you figure out the impedance of various random wires of different gauges?? John Doty's article mentioned an 18 gauge wire hung more than a few feet above the ground, but I'm just curious what sort of differences there would be using, say, 14, 16 or 22 gauge wire in a similar scenario. I can't imagine trying to test it without a load of some sort. --Mike L. The size (gauge) of the wire is not important for a *reception* antenna. It does matter for a transmitting antenna. The typical inverted-L has an impedance of several hundred ohms for much of it's frequency range. That's why a 9:1 (impedance) balun is often used. If the receiver has an antenna input impedance of about 50-ohms, a 9:1 balun will match it to a 450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is actually 3:1. My balun has a primary winding with 10-turns and a secondary with 30-turns. I used #22 enameled wire on a 1/2" dia. type-43 ferrite core. I plan to make a new balun using a 'binocular' core. This core shape makes the balun's impedance more consistent throughout it's frequency range. Is there much of a difference in the gauge of the enameled wire wound around the core?? I followed John Bryant's lead in his article and used 30 gauge wire, but I was thinking that 26 would be easier to handle. --Mike L. |
Michael Lawson wrote: "starman" wrote in message ... Michael Lawson wrote: "starman" wrote in message ... Pierre Vachon wrote: Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? I am a little limited in space as my yard is only 75 feet long and there are power lines at the front. I assume that they are the source of an irritating hum on the receiver on certain frequencies. Thanks for the help in advance. Pierre A real longwire antenna is much longer than what you are thinking of building. The antenna you describe is called a 'random wire' or inverted-L. This kind of antenna is not tuned for a specific band or range of frequencies. In fact, it performs well throughout the shortwave spectrum. See the following website for instructions on building a good low noise inverted-L antenna. I use this kind with my R8B. http://www.anarc.org/naswa/badx/ante...e_antenna.html Hmm. That brings up a question that I'd thought of earlier, but when I was writing my posts, I forgot to put it in. How do you figure out the impedance of various random wires of different gauges?? John Doty's article mentioned an 18 gauge wire hung more than a few feet above the ground, but I'm just curious what sort of differences there would be using, say, 14, 16 or 22 gauge wire in a similar scenario. I can't imagine trying to test it without a load of some sort. --Mike L. The size (gauge) of the wire is not important for a *reception* antenna. It does matter for a transmitting antenna. The typical inverted-L has an impedance of several hundred ohms for much of it's frequency range. That's why a 9:1 (impedance) balun is often used. If the receiver has an antenna input impedance of about 50-ohms, a 9:1 balun will match it to a 450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is actually 3:1. My balun has a primary winding with 10-turns and a secondary with 30-turns. I used #22 enameled wire on a 1/2" dia. type-43 ferrite core. I plan to make a new balun using a 'binocular' core. This core shape makes the balun's impedance more consistent throughout it's frequency range. Is there much of a difference in the gauge of the enameled wire wound around the core?? I followed John Bryant's lead in his article and used 30 gauge wire, but I was thinking that 26 would be easier to handle. 26 will work just fine. I've typically used 22. dxAce Michigan USA http://www.iserv.net/~n8kdv/dxpage.htm |
Hi RHF, I used to subscribe to it but I tend to change hobbies in the Summer
LOL..Anyway, last year I remember we were trying to have a net (so to speak) on hf and it never really materialized. When summer hit I was back into my other hobby of motorcycles..I should resubscribe though, if I remember correctly there was a pretty good group there..Thanks again for the invite.. Steve kb8viv |
Michael Lawson wrote:
"starman" wrote in message The size (gauge) of the wire is not important for a *reception* antenna. It does matter for a transmitting antenna. The typical inverted-L has an impedance of several hundred ohms for much of it's frequency range. That's why a 9:1 (impedance) balun is often used. If the receiver has an antenna input impedance of about 50-ohms, a 9:1 balun will match it to a 450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is actually 3:1. My balun has a primary winding with 10-turns and a secondary with 30-turns. I used #22 enameled wire on a 1/2" dia. type-43 ferrite core. I plan to make a new balun using a 'binocular' core. This core shape makes the balun's impedance more consistent throughout it's frequency range. Is there much of a difference in the gauge of the enameled wire wound around the core?? I followed John Bryant's lead in his article and used 30 gauge wire, but I was thinking that 26 would be easier to handle. --Mike L. Use whatever size wire works best on the ferrite core you have. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
= = = starman wrote in message
= = = ... Michael Lawson wrote: "starman" wrote in message The size (gauge) of the wire is not important for a *reception* antenna. It does matter for a transmitting antenna. The typical inverted-L has an impedance of several hundred ohms for much of it's frequency range. That's why a 9:1 (impedance) balun is often used. If the receiver has an antenna input impedance of about 50-ohms, a 9:1 balun will match it to a 450-ohm antenna (9x50=450). The wire turns ratio for a 9:1 balun is actually 3:1. My balun has a primary winding with 10-turns and a secondary with 30-turns. I used #22 enameled wire on a 1/2" dia. type-43 ferrite core. I plan to make a new balun using a 'binocular' core. This core shape makes the balun's impedance more consistent throughout it's frequency range. Is there much of a difference in the gauge of the enameled wire wound around the core?? I followed John Bryant's lead in his article and used 30 gauge wire, but I was thinking that 26 would be easier to handle. --Mike L. Use whatever size wire works best on the ferrite core you have. STARMAN, Isn't Type 43 the recommended as a Balun "Core Material" ? Why isn't Type 61 also a 'suggested' Balun Core Material ? NOTE: Matching Transformer = Balun = UnUn True Story: A while back I bought a Grab Bag of Feritte Cores on eBay. Some of them had a #20 Enameled Wire wrapped on them with 36 Turns. They were about 1" OD x 1/2" ID x 1/2" H. So I thought, why not try them as an Matching Transformer on an 'old' Telephone Two Wire Service Line (pre-1950s) that runs overhead about 75 Ft from the Power Pole to the House. Being lazy I simply wrapped a Twelve Turn (12T) Secondary and wired it up with a #22 Magnet Wire from a RadioShack 'three pack' Catalog # 278-1345 ($5). Well 36:12 Turns worked good for AM/MW and up to 7 MHz but the Signal Levels fell off after 7 MHz. So then I tried Reducing the Primary to 30 Turns and the Secondary to 10 Turns. Again the AM/MW Band was good and the Shortwave coverage went up to 23 MHz. Not being one to settle for 'good enough'; I then tried Reducing the Primary to 24 Turns and the Secondary to 8 Turns. Well the AM/MW Reception went down and the Shortwave Bands reception picked up to the CB Band. So it seems that the 'majic' 30 Turns and 10 Turns worked the best for my needs using this ?Core?. TESTING: The receiver for this Test was an Icom IC-R75. http://www.icomamerica.com/products/receivers/r75/ My Matching Transformer "Test Standard" was an ICE 180A. http://www.arraysolutions.com/Produc...age%20Matching My Test Measurement were with "My Ears" and 'My Eyes' (S-Meter). The 'old' Telephone Service Line was a Two Wire (Copper Clad Steel?) Cable. One Wire was used for the ICE 180A and the other Wire was used for the ?Core? Matching Transformer. FWIW: Reading your statement about the Binocular Cores, I have just ordered some from Universal-Radio.Com to Test. It is my understanding that One Turn 'counts' for Two when You use a Binocular Core. Now Is That True ? Also, I have a SWL 10:1 Balun that is made by "RF Junkie" and will be testing it soon using the same test-set-up. * Two Shortwave Listener (SWL) 10:1 Baluns for Random Wire Antennas http://groups.yahoo.com/group/Shortw...a/message/1523 iane ~ RHF .. .. |
(RHF) wrote in message m...
Good information snipped STARMAN, Isn't Type 43 the recommended as a Balun "Core Material" ? Why isn't Type 61 also a 'suggested' Balun Core Material ? NOTE: Matching Transformer = Balun = UnUn True Story: A while back I bought a Grab Bag of Feritte Cores on eBay. Some of them had a #20 Enameled Wire wrapped on them with 36 Turns. They were about 1" OD x 1/2" ID x 1/2" H. So I thought, why not try them as an Matching Transformer on an 'old' Telephone Two Wire Service Line (pre-1950s) that runs overhead about 75 Ft from the Power Pole to the House. Being lazy I simply wrapped a Twelve Turn (12T) Secondary and wired it up with a #22 Magnet Wire from a RadioShack 'three pack' Catalog # 278-1345 ($5). Well 36:12 Turns worked good for AM/MW and up to 7 MHz but the Signal Levels fell off after 7 MHz. So then I tried Reducing the Primary to 30 Turns and the Secondary to 10 Turns. Again the AM/MW Band was good and the Shortwave coverage went up to 23 MHz. Not being one to settle for 'good enough'; I then tried Reducing the Primary to 24 Turns and the Secondary to 8 Turns. Well the AM/MW Reception went down and the Shortwave Bands reception picked up to the CB Band. So it seems that the 'majic' 30 Turns and 10 Turns worked the best for my needs using this ?Core?. RHF - it sounds like you did not know what the material for this core was (43 vs. 61 or other) - right? Is it possible that the frequency range is more dependent on the number of turns (inductance?) than the actual material? This is not a trick question... TESTING: The receiver for this Test was an Icom IC-R75. http://www.icomamerica.com/products/receivers/r75/ My Matching Transformer "Test Standard" was an ICE 180A. http://www.arraysolutions.com/Produc...age%20Matching My Test Measurement were with "My Ears" and 'My Eyes' (S-Meter). The 'old' Telephone Service Line was a Two Wire (Copper Clad Steel?) Cable. One Wire was used for the ICE 180A and the other Wire was used for the ?Core? Matching Transformer. Question - what is the advantage of using the ICE 180A (1.5-30 MHz) over the 180C (0.1 - 30 MHz)? Is the 180A inherently better suited to SW because it does not need to be so broadbanded? Or will the other work as well, PLUS get you MW? Do these use binocular cores? Or just one of them? FWIW: Reading your statement about the Binocular Cores, I have just ordered some from Universal-Radio.Com to Test. It is my understanding that One Turn 'counts' for Two when You use a Binocular Core. Now Is That True ? I would love to know this also, and also see a GOOD diagram of how to wire a binocular core. Also, I have a SWL 10:1 Balun that is made by "RF Junkie" and will be testing it soon using the same test-set-up. * Two Shortwave Listener (SWL) 10:1 Baluns for Random Wire Antennas http://groups.yahoo.com/group/Shortw...a/message/1523 It is great to see all these fine antenna posts - becoming familiar with the experience of others, and ultimately (hopefully) contributing something that may help others, is the best and highest use of this medium, I think (oh, yeah, that and name-calling over politics ;-) Bruce Jensen |
In article ,
(bpnjensen) wrote: (RHF) wrote in message m... Good information snipped STARMAN, Isn't Type 43 the recommended as a Balun "Core Material" ? Why isn't Type 61 also a 'suggested' Balun Core Material ? NOTE: Matching Transformer = Balun = UnUn True Story: A while back I bought a Grab Bag of Feritte Cores on eBay. Some of them had a #20 Enameled Wire wrapped on them with 36 Turns. They were about 1" OD x 1/2" ID x 1/2" H. So I thought, why not try them as an Matching Transformer on an 'old' Telephone Two Wire Service Line (pre-1950s) that runs overhead about 75 Ft from the Power Pole to the House. Being lazy I simply wrapped a Twelve Turn (12T) Secondary and wired it up with a #22 Magnet Wire from a RadioShack 'three pack' Catalog # 278-1345 ($5). Well 36:12 Turns worked good for AM/MW and up to 7 MHz but the Signal Levels fell off after 7 MHz. So then I tried Reducing the Primary to 30 Turns and the Secondary to 10 Turns. Again the AM/MW Band was good and the Shortwave coverage went up to 23 MHz. Not being one to settle for 'good enough'; I then tried Reducing the Primary to 24 Turns and the Secondary to 8 Turns. Well the AM/MW Reception went down and the Shortwave Bands reception picked up to the CB Band. So it seems that the 'majic' 30 Turns and 10 Turns worked the best for my needs using this ?Core?. RHF - it sounds like you did not know what the material for this core was (43 vs. 61 or other) - right? Is it possible that the frequency range is more dependent on the number of turns (inductance?) than the actual material? This is not a trick question... Well, actually in a way it is a trick question. Inductors and transformers are complex devices. Small differences in construction will have a large effect on performance. How you connect it will change its performance. Where (in frequency) you make measurement will affect the results. I mention this because you want it to work from .5 MHz to 30 MHz. -- Telamon Ventura, California |
Isn't Type 43 the recommended as a Balun "Core Material" ?
Type 43 is optimal for the shortwave (HF) spectrum. Why isn't Type 61 also a 'suggested' Balun Core Material ? The 'Q' of type-61 makes it too selective for HF. You want the balun to be broadband not peaked for a particular frequency. Is it possible that the frequency range is more dependent on the number of turns (inductance?) than the actual material? This is not a trick question... The ferrite composition plays a large role in determining the effective frequency range of the coil. In the case of a balun/unun you're not trying to make a tuned coil. You want it to be efficient over the desired frequency range. See the following webpage for ferrite core info': http://www.universal-radio.com/catal.../amidonT1.html FWIW: Reading your statement about the Binocular Cores, I have just ordered some from Universal-Radio.Com to Test. It is my understanding that One Turn 'counts' for Two when You use a Binocular Core. Now Is That True ? I would love to know this also, and also see a GOOD diagram of how to wire a binocular core. Here's how to wind ferrite cores, including binocular ones: http://www.oselectronics.com/downloa...ansformers.pdf ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
(bpnjensen) wrote:
Question - what is the advantage of using the ICE 180A (1.5-30 MHz) over the 180C (0.1 - 30 MHz)? Is the 180A inherently better suited to SW because it does not need to be so broadbanded? Or will the other work as well, PLUS get you MW? Do these use binocular cores? Or just one of them? Both use binocular cores -- I have a 180 and a 182. The only visible difference is that the DC blocking capaccitor. The binocular may be different. I wondered about the difference as well, and the only thing I could think of is that the smaller value of the blocking capacitor on the 180A helps attenuate MW and LW, which certain radios' front ends can't handle. -- Eric F. Richards, "Making me root for a sanctimonious statist blowhard like Kerry isn't the worst thing Bush has done to the country. But it's the offense that I take most personally." -- http://www.reason.com/links/links071304.shtml |
= = = (bpnjensen) wrote in message
= = = . com... (RHF) wrote in message m... Good information snipped STARMAN, Isn't Type 43 the recommended as a Balun "Core Material" ? Why isn't Type 61 also a 'suggested' Balun Core Material ? NOTE: Matching Transformer = Balun = UnUn True Story: A while back I bought a Grab Bag of Feritte Cores on eBay. Some of them had a #20 Enameled Wire wrapped on them with 36 Turns. They were about 1" OD x 1/2" ID x 1/2" H. So I thought, why not try them as an Matching Transformer on an 'old' Telephone Two Wire Service Line (pre-1950s) that runs overhead about 75 Ft from the Power Pole to the House. Being lazy I simply wrapped a Twelve Turn (12T) Secondary and wired it up with a #22 Magnet Wire from a RadioShack 'three pack' Catalog # 278-1345 ($5). Well 36:12 Turns worked good for AM/MW and up to 7 MHz but the Signal Levels fell off after 7 MHz. So then I tried Reducing the Primary to 30 Turns and the Secondary to 10 Turns. Again the AM/MW Band was good and the Shortwave coverage went up to 23 MHz. Not being one to settle for 'good enough'; I then tried Reducing the Primary to 24 Turns and the Secondary to 8 Turns. Well the AM/MW Reception went down and the Shortwave Bands reception picked up to the CB Band. So it seems that the 'majic' 30 Turns and 10 Turns worked the best for my needs using this ?Core?. RHF - it sounds like you did not know what the material for this core was (43 vs. 61 or other) - right? Is it possible that the frequency range is more dependent on the number of turns (inductance?) than the actual material? This is not a trick question... BJ, YES - I DID NOT KNOW - I think that sometimes you just get 'lucky' :o) READ: Assessing unknown Ferrite Toroids http://www.alan.melia.btinternet.co.uk/toroids.htm As for Me the whole "ART" and 'science' {mystery] of SWL Antennas is: * Read & Think * Build & Do * Surprise & Enjoy Afer all, I am simply a SWL and Not On A Power Trip ~ RHF { No Transmitter Required } .. .. TESTING: The receiver for this Test was an Icom IC-R75. http://www.icomamerica.com/products/receivers/r75/ My Matching Transformer "Test Standard" was an ICE 180A. http://www.arraysolutions.com/Produc...age%20Matching My Test Measurement were with "My Ears" and 'My Eyes' (S-Meter). The 'old' Telephone Service Line was a Two Wire (Copper Clad Steel?) Cable. One Wire was used for the ICE 180A and the other Wire was used for the ?Core? Matching Transformer. Question - what is the advantage of using the ICE 180A (1.5-30 MHz) over the 180C (0.1 - 30 MHz)? Is the 180A inherently better suited to SW because it does not need to be so broadbanded? Or will the other work as well, PLUS get you MW? Do these use binocular cores? Or just one of them? I bought the ICE 180A and it seems to work very well down through the AM/MW Broadcast Band (500 kHz) although it's listed Coverage is 1.5 MHz to 30 MHz. The ICE 182A Beverage Matching (Isolation) Unit has a listed Coverage of 100 kHz to 30 MHz. http://www.arraysolutions.com/Produc...age%20Matching As to the Debate about what makes an ICE 180A and an ICE 182A 'different': "IDK" - I DON'T KNOW ! {Did 'mister-know-it-all' Really Say "IDK" :o} .. .. FWIW: Reading your statement about the Binocular Cores, I have just ordered some from Universal-Radio.Com to Test. It is my understanding that One Turn 'counts' for Two when You use a Binocular Core. Now Is That True ? I would love to know this also, and also see a GOOD diagram of how to wire a binocular core. Concerning the 'topic' of Binocular Core Matching Transformers her are a several Links/URLs to take-a-look at: * Multi-Aperture Cores http://partsandkits.com/binocular.html http://www.cwsbytemark.com/CatalogSh...Files/2_34.pdf * Wide Band RF Transformers http://www.electronics-tutorials.com...ansformers.htm * * What are Toroids ? http://www.electronics-tutorials.com/basics/toroids.htm * RF Transformer - Mini-Circuits http://rust.lbl.gov/~gtp/DOM/dataShe.../tranfrmr.html * Inductors: Binocular Balun Cores - Surplus Sales http://www.surplussales.com/FerMisc/FerMisc-5.html * Construction and Use of Broad Band Transformers - Figuer #2 http://www.oselectronics.com/downloa...ansformers.pdf * Amidon #43 & #61 Material Two-Hole or Binocular Cores http://www.amidoncorp.com/aai_woundbeads.htm * Impedance Matching Transformers for Receiving Antennas at Medium and Lower Shortwave Frequencies Bill Bowers - John Bryant - Nick Hall-Patch [VE7DXR] http://www.dxing.info/equipment/impe...ing_bryant.doc http://www.dxing.info/equipment/impe...mer_bryant.doc * Baluns - Kits & Custom - The WireMan http://thewireman.com/baluns.html * Baluns in Theory - RadioWorks http://radioworks.com/nbalun.html * Toroidal Balun Kits, Toroids and Enamelled Wire Packs - OZ-Gear http://www.ozgear.com.au/balun/ToroidalBalunKits.htm * Balun and Transformer Core Selection - Binocular Core Image http://www.w8ji.com/core_selection.htm .. .. Also, I have a SWL 10:1 Balun that is made by "RF Junkie" and will be testing it soon using the same test-set-up. * Two Shortwave Listener (SWL) 10:1 Baluns for Random Wire Antennas http://groups.yahoo.com/group/Shortw...a/message/1523 It is great to see all these fine antenna posts - becoming familiar with the experience of others, and ultimately (hopefully) contributing something that may help others, is the best and highest use of this medium, I think (oh, yeah, that and name-calling over politics ;-) Bruce Jensen iane ~ RHF .. .. |
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