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Homemade AM ferrite antenna question
I want to try to make a homemade ferrite antenna to improve the AM reception on
an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
Elfa: - Tried looking here ?? http://www.hard-core-dx.com/nordicdx/antenna/ Dan In article , elfa writes: I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
You can buy them wound and all from several places.
Bill, N5NOB |
ELFA,
I suggest that you first consider using a simple Box Loop Antenna. Check-Out the "Loop Antennas" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/loopantennas/ Also the new "Ferrite Rod Antenna Experimenters" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/FerriteRodAntenna/ ~ RHF .. .. = = = elfa = = = wrote in message ... I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
In article , RHF says...
ELFA, I suggest that you first consider using a simple Box Loop Antenna. Appreciate the suggestion RHF, but this is for an electronic education I'm trying to give myself. All I want to do is make a ferrite antenna myself to see if I can actually do it. elfa Check-Out the "Loop Antennas" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/loopantennas/ Also the new "Ferrite Rod Antenna Experimenters" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/FerriteRodAntenna/ ~ RHF . . = = = elfa = = = wrote in message ... I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
elfa wrote in :
Appreciate the suggestion RHF, but this is for an electronic education I'm trying to give myself. All I want to do is make a ferrite antenna myself to see if I can actually do it. Anybody can do it. All you need is a ferrite bar, some wire, and a little bit of common sense. |
In article , donutbandit says...
elfa wrote in : Appreciate the suggestion RHF, but this is for an electronic education I'm trying to give myself. All I want to do is make a ferrite antenna myself to see if I can actually do it. Anybody can do it. All you need is a ferrite bar, some wire, and a little bit of common sense. Would you care to enlighten me? Are there a certain number of turns based on length of ferrite bar? elfa |
ELFA,
OK I will bite; here are a few questions: Is this going to be a stand-a-lone 'external' AM/MW Ferrite Rod Antenna (FRA) to be used with any radio/receiver ? - These usually have a single winding and variable tuning capacitor. - - They can be used by 'inductively coupling' them to Radios with a built-in AM/MW FRA. - - - They can be used by 'direct connection' to Receivers with External Antenna Inputs (that lack a AM/MW FRA). NOTE: Sometimes they are built with a 'connection' for an External Antenna, and are used to 'couple' and 'tune' this External Antenna for the AM/MW Band. Or, is this going to be a unique 'internal' AM/MW Ferrite Rod Antenna to be used as a 'replacement' for the existing FRA in a radio/receiver that you already have ? - Most of the time these have two windings and you will have to closely examine the original FRA to determine your physical starting points to build your replacement FRA for this specific radio/receiver. WINDINGS: - Number Windings both Primary and Secondary of the FRA. - - Position of both sets of Windings on the FRA. - - - Then you must start the trial and error process of getting-it-right for that radio/receiver. iane ~ RHF .. .. = = = elfa = = = wrote in message ... In article , RHF says... ELFA, I suggest that you first consider using a simple Box Loop Antenna. Appreciate the suggestion RHF, but this is for an electronic education I'm trying to give myself. All I want to do is make a ferrite antenna myself to see if I can actually do it. elfa Check-Out the "Loop Antennas" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/loopantennas/ Also the new "Ferrite Rod Antenna Experimenters" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/FerriteRodAntenna/ ~ RHF . . = = = elfa = = = wrote in message ... I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
In article , RHF says...
ELFA, OK I will bite; here are a few questions: Is this going to be a stand-a-lone 'external' AM/MW Ferrite Rod Antenna (FRA) to be used with any radio/receiver ? - These usually have a single winding and variable tuning capacitor. - - They can be used by 'inductively coupling' them to Radios with a built-in AM/MW FRA. - - - They can be used by 'direct connection' to Receivers with External Antenna Inputs (that lack a AM/MW FRA). NOTE: Sometimes they are built with a 'connection' for an External Antenna, and are used to 'couple' and 'tune' this External Antenna for the AM/MW Band. Or, is this going to be a unique 'internal' AM/MW Ferrite Rod Antenna to be used as a 'replacement' for the existing FRA in a radio/receiver that you already have ? - Most of the time these have two windings and you will have to closely examine the original FRA to determine your physical starting points to build your replacement FRA for this specific radio/receiver. WINDINGS: - Number Windings both Primary and Secondary of the FRA. - - Position of both sets of Windings on the FRA. - - - Then you must start the trial and error process of getting-it-right for that radio/receiver. iane ~ RHF You're too far ahead of me RHF. I haven't a clue as to how they work. All I wanted to do was just make one 2 times as big as on in a junk radio to see if I can get stations better based on size of antenna. At this point, I can't find a website that even explains windings etc. elfa . . = = = elfa = = = wrote in message ... In article , RHF says... ELFA, I suggest that you first consider using a simple Box Loop Antenna. Appreciate the suggestion RHF, but this is for an electronic education I'm trying to give myself. All I want to do is make a ferrite antenna myself to see if I can actually do it. elfa Check-Out the "Loop Antennas" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/loopantennas/ Also the new "Ferrite Rod Antenna Experimenters" eGroup on YAHOO ! - - - http://groups.yahoo.com/group/FerriteRodAntenna/ ~ RHF . . = = = elfa = = = wrote in message ... I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
elfa wrote:
You're too far ahead of me RHF. I haven't a clue as to how they work. All I wanted to do was just make one 2 times as big as on in a junk radio to see if I can get stations better based on size of antenna. At this point, I can't find a website that even explains windings etc. elfa Forget the ferrite and go for a big loop? http://www.mindspring.com/~loop_antenna/ -Bill |
They are a tuned resonant circuit the same as a box loop. Half of that
resonant circuit is in the radio. Due to differences in the circuitry, there is hardly a way to just say "take a ferrite rod and wind X number of turns on it". I could tell you how to do it, including the math necessary, if you really want to get that deep. If not, and you just want performance, build a box loop. Lots easier and plans are readily available. " You're too far ahead of me RHF. I haven't a clue as to how they work. All I wanted to do was just make one 2 times as big as on in a junk radio to see if I can get stations better based on size of antenna. At this point, I can't find a website that even explains windings etc. |
elfa wrote in :
You're too far ahead of me RHF. I haven't a clue as to how they work. All I wanted to do was just make one 2 times as big as on in a junk radio to see if I can get stations better based on size of antenna. At this point, I can't find a website that even explains windings etc. My God, can't anybody do anything any more without having to consort with the Internet and get permission from the Netizens? You wind some wire on a ferrite bar. You put a variable capacitor across it and see how it tunes. You adjust the windings until you get what you are looking for. Do you need toilet training instructions, as well? |
In article , donutbandit says...
elfa wrote in : You're too far ahead of me RHF. I haven't a clue as to how they work. All I wanted to do was just make one 2 times as big as on in a junk radio to see if I can get stations better based on size of antenna. At this point, I can't find a website that even explains windings etc. My God, can't anybody do anything any more without having to consort with the Internet and get permission from the Netizens? You wind some wire on a ferrite bar. You put a variable capacitor across it and see how it tunes. You adjust the windings until you get what you are looking for. Do you need toilet training instructions, as well? No...no need for the toilet training instructions. I can **** in your face without consulting a manual. elfa |
Elfa, I hope you plonked this guy, you didn't deserve that.
"elfa" wrote in message ... In article , donutbandit says... No...no need for the toilet training instructions. I can **** in your face without consulting a manual. elfa |
In article E_Gkb.598055$cF.262444@rwcrnsc53, CW says...
Elfa, I hope you plonked this guy, you didn't deserve that. It's the main reason I rarely visit this group. Too many blowhards and not enough of those with genuine expertise. I appreciate your offer of instructions re the ferrite bar antenna but I think I'll just skip it for now. This was the wrong group for this kind of request. It should have been in an electronics group. elfa "elfa" wrote in message ... In article , donutbandit says... No...no need for the toilet training instructions. I can **** in your face without consulting a manual. elfa |
"elfa" wrote in message ... I appreciate your offer of instructions re the ferrite bar antenna but I think I'll just skip it for now. This was the wrong group for this kind of request. It should have been in an electronics group. elfa The number of turns necessary for a loopstick antenna depends on several factors. 1) the frequency range required 2) the permeability of the ferrite core 3) the spacing of the turns For experimentation purposes, you might start with about 80 turns of AWG 30 enameled or cloth covered wire, contiguously spaced, near one end of the core. With this, use a ~360 pF variable capacitor. If you have a grid dip meter, you can easily find where this is resonant. If you don't, then you have to poke about on the AM dial of a cheap radio, and see where you can tune it. |
Good strategy is to make a guess and wind some extra turns. Then find out
whre you are. It is easier to to remove the extra turns than wind some more. Adding the windings expects you to make solder joints, maybe several ones. timo "Brenda Ann" wrote in message ... "elfa" wrote in message ... I appreciate your offer of instructions re the ferrite bar antenna but I think I'll just skip it for now. This was the wrong group for this kind of request. It should have been in an electronics group. elfa The number of turns necessary for a loopstick antenna depends on several factors. 1) the frequency range required 2) the permeability of the ferrite core 3) the spacing of the turns For experimentation purposes, you might start with about 80 turns of AWG 30 enameled or cloth covered wire, contiguously spaced, near one end of the core. With this, use a ~360 pF variable capacitor. If you have a grid dip meter, you can easily find where this is resonant. If you don't, then you have to poke about on the AM dial of a cheap radio, and see where you can tune it. |
Brenda,
thanks for the info... May try it myself ! Dan In article , "Brenda Ann" writes: "elfa" wrote in message ... I appreciate your offer of instructions re the ferrite bar antenna but I think I'll just skip it for now. This was the wrong group for this kind of request. It should have been in an electronics group. elfa The number of turns necessary for a loopstick antenna depends on several factors. 1) the frequency range required 2) the permeability of the ferrite core 3) the spacing of the turns For experimentation purposes, you might start with about 80 turns of AWG 30 enameled or cloth covered wire, contiguously spaced, near one end of the core. With this, use a ~360 pF variable capacitor. If you have a grid dip meter, you can easily find where this is resonant. If you don't, then you have to poke about on the AM dial of a cheap radio, and see where you can tune it. |
This was the wrong group for this kind of request.
It should have been in an electronics group. Actually, this group has fielded ferrite, air core, active and passive loop designs hundreds of times over the years. Do an archive search under loops, or loop construction. Or, do the same kind of search on an engine somewhere. But this group is a VERY good place for such info, the usual idiots notwithstanding. In fact you'll get a better answer here than a lot of places, even if you do have to put up with a few things in the meantime, if only because the serious and helpful replies you DO get are coming from people with real-world experience over many years in antenna experimentation. I've been in this group off and on for many years, and while I've also had my share of flame wars and idiot posts, a GREAT deal of the antenna experience I have gained has come directly (and in some cases *exclusively*) from this group. Linus |
don't quit the group elfa.
that question was very appropriate for rec.radio.sw I have found this to be the best place to ask MW/AM radio and antenna questions. Just ignore the reptiles that come out from under their rocks. You have to sift and sort thru the replies, but there are some very knowledgeable,helpful and friendly posters here. I have learned a lot from them in the past several years. 73 Russ K3Pi |
ELFA,
"BA" gave you some good advise. Before you start the windings. * Find a 6.5" to 8" Ferrite Rod Antenna (FRA). * 10 Feet of Wire (Magnet or Litz) * Cut a 2" X 2" piece of Typing/Copier Paper 20/24LB) * Wrap the Copier Paper around the FRA (About Two(2) Layers & Tape the Joint) - - - The Copier Paper will 'form' a "Tube" that can be moved on the FRA. * Wrap 50-80 Wire Windings over the Copier Paper Tube to form a "Moveable Coil Assembly (The Coil). * Set the Windings at the very tip of one of the Ends of the FRA. * Connect the Variable "Tuning" 360-400pf Capacitor (VTC) to the Leads from the Windings. # Place the FRA and VTC next to a Radio: Ideally you would use a Radio with a Digital Frequncy Display and a "S" Meter. * Starting-Mid-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the Middle of the AM/MW Band 800-1000 kHz. - Set the VTC to its Middle/Center Position. - - Very Slowly 'move' The Coil from the Tip of the FRA towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. Note: If you 'find' a "Sweet Spot" on this first try: You have Luck-Out ! * Top-End-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the High-End of the AM/MW Band 1500-1700 kHz. - Set the VTC to its Fully "OPEN" Position. - - Very Slowly 'move' The Coil from the 'prior' (Starting-Mid-Point) position towards the Tip of the FRA and then towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. * Bottom-End-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the Low-End of the AM/MW Band 550-700 kHz. - Set the VTC to its Fully "CLOSED" Position. - - Very Slowly 'move' The Coil from the 'prior' (Top-End-Point) position towards the Tip of the FRA and then towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. NOTE: Ideally these three points are within a 1/8" of each other and you would set The Coil in the the middle of the three. However the reality is that this will not be the case and you will have to REMOVE/ADD a few Windings and try the above process again. TIP: If you can "Tune" the Low-End and/or Middle of the AM/MW Band then REMOVE a few Windings. Or, if you can "Tune" the High-End and/or Middle of the AM/MW Band then ADD a few Windings. iane ~ RHF .. .. = = = "Brenda Ann" = = = wrote in message ... "elfa" wrote in message ... I appreciate your offer of instructions re the ferrite bar antenna but I think I'll just skip it for now. This was the wrong group for this kind of request. It should have been in an electronics group. elfa The number of turns necessary for a loopstick antenna depends on several factors. 1) the frequency range required 2) the permeability of the ferrite core 3) the spacing of the turns For experimentation purposes, you might start with about 80 turns of AWG 30 enameled or cloth covered wire, contiguously spaced, near one end of the core. With this, use a ~360 pF variable capacitor. If you have a grid dip meter, you can easily find where this is resonant. If you don't, then you have to poke about on the AM dial of a cheap radio, and see where you can tune it. |
RHF,
That post just made it into my "save" file. Thanks for the excellent instruction. -- Stinger "RHF" wrote in message om... ELFA, "BA" gave you some good advise. Before you start the windings. * Find a 6.5" to 8" Ferrite Rod Antenna (FRA). * 10 Feet of Wire (Magnet or Litz) * Cut a 2" X 2" piece of Typing/Copier Paper 20/24LB) * Wrap the Copier Paper around the FRA (About Two(2) Layers & Tape the Joint) - - - The Copier Paper will 'form' a "Tube" that can be moved on the FRA. * Wrap 50-80 Wire Windings over the Copier Paper Tube to form a "Moveable Coil Assembly (The Coil). * Set the Windings at the very tip of one of the Ends of the FRA. * Connect the Variable "Tuning" 360-400pf Capacitor (VTC) to the Leads from the Windings. # Place the FRA and VTC next to a Radio: Ideally you would use a Radio with a Digital Frequncy Display and a "S" Meter. * Starting-Mid-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the Middle of the AM/MW Band 800-1000 kHz. - Set the VTC to its Middle/Center Position. - - Very Slowly 'move' The Coil from the Tip of the FRA towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. Note: If you 'find' a "Sweet Spot" on this first try: You have Luck-Out ! * Top-End-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the High-End of the AM/MW Band 1500-1700 kHz. - Set the VTC to its Fully "OPEN" Position. - - Very Slowly 'move' The Coil from the 'prior' (Starting-Mid-Point) position towards the Tip of the FRA and then towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. * Bottom-End-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the Low-End of the AM/MW Band 550-700 kHz. - Set the VTC to its Fully "CLOSED" Position. - - Very Slowly 'move' The Coil from the 'prior' (Top-End-Point) position towards the Tip of the FRA and then towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. NOTE: Ideally these three points are within a 1/8" of each other and you would set The Coil in the the middle of the three. However the reality is that this will not be the case and you will have to REMOVE/ADD a few Windings and try the above process again. TIP: If you can "Tune" the Low-End and/or Middle of the AM/MW Band then REMOVE a few Windings. Or, if you can "Tune" the High-End and/or Middle of the AM/MW Band then ADD a few Windings. iane ~ RHF . . = = = "Brenda Ann" = = = wrote in message ... "elfa" wrote in message ... I appreciate your offer of instructions re the ferrite bar antenna but I think I'll just skip it for now. This was the wrong group for this kind of request. It should have been in an electronics group. elfa The number of turns necessary for a loopstick antenna depends on several factors. 1) the frequency range required 2) the permeability of the ferrite core 3) the spacing of the turns For experimentation purposes, you might start with about 80 turns of AWG 30 enameled or cloth covered wire, contiguously spaced, near one end of the core. With this, use a ~360 pF variable capacitor. If you have a grid dip meter, you can easily find where this is resonant. If you don't, then you have to poke about on the AM dial of a cheap radio, and see where you can tune it. |
Stinger,
Thank You, ELFA did not indicate that he had any test equipment Grid Dip Meter etc. So this was the simplest method by just using a basic AM/MW Radio. A Copy of this simple method is posted to: * " Ferrite Rod Antenna for Experimenters" eGroup on YAHOO! http://groups.yahoo.com/group/FerriteRodAntenna/ * "SWL Antennas and AM & FM Antennas" eGroup on YAHOO! http://groups.yahoo.com/group/SWL-AM-FM-Antenna/ ~ RHF .. .. = = = "Stinger" = = = wrote in message ... RHF, That post just made it into my "save" file. Thanks for the excellent instruction. -- Stinger "RHF" wrote in message om... ELFA, "BA" gave you some good advise. Before you start the windings. * Find a 6.5" to 8" Ferrite Rod Antenna (FRA). * 10 Feet of Wire (Magnet or Litz) * Cut a 2" X 2" piece of Typing/Copier Paper 20/24LB) * Wrap the Copier Paper around the FRA (About Two(2) Layers & Tape the Joint) - - - The Copier Paper will 'form' a "Tube" that can be moved on the FRA. * Wrap 50-80 Wire Windings over the Copier Paper Tube to form a "Moveable Coil Assembly (The Coil). * Set the Windings at the very tip of one of the Ends of the FRA. * Connect the Variable "Tuning" 360-400pf Capacitor (VTC) to the Leads from the Windings. # Place the FRA and VTC next to a Radio: Ideally you would use a Radio with a Digital Frequncy Display and a "S" Meter. * Starting-Mid-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the Middle of the AM/MW Band 800-1000 kHz. - Set the VTC to its Middle/Center Position. - - Very Slowly 'move' The Coil from the Tip of the FRA towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. Note: If you 'find' a "Sweet Spot" on this first try: You have Luck-Out ! * Top-End-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the High-End of the AM/MW Band 1500-1700 kHz. - Set the VTC to its Fully "OPEN" Position. - - Very Slowly 'move' The Coil from the 'prior' (Starting-Mid-Point) position towards the Tip of the FRA and then towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. * Bottom-End-Point: "Tune" the Radio to a medium strength AM/MW Radio Station at the Low-End of the AM/MW Band 550-700 kHz. - Set the VTC to its Fully "CLOSED" Position. - - Very Slowly 'move' The Coil from the 'prior' (Top-End-Point) position towards the Tip of the FRA and then towards the center of the FRA. - - - Try to identify by Ear or Eye an change in the Quality and Strength of Reception. - - - - Mark-Measure-Record this 'position'. NOTE: Ideally these three points are within a 1/8" of each other and you would set The Coil in the the middle of the three. However the reality is that this will not be the case and you will have to REMOVE/ADD a few Windings and try the above process again. TIP: If you can "Tune" the Low-End and/or Middle of the AM/MW Band then REMOVE a few Windings. Or, if you can "Tune" the High-End and/or Middle of the AM/MW Band then ADD a few Windings. iane ~ RHF . . = = = "Brenda Ann" = = = wrote in message ... "elfa" wrote in message ... I appreciate your offer of instructions re the ferrite bar antenna but I think I'll just skip it for now. This was the wrong group for this kind of request. It should have been in an electronics group. elfa The number of turns necessary for a loopstick antenna depends on several factors. 1) the frequency range required 2) the permeability of the ferrite core 3) the spacing of the turns For experimentation purposes, you might start with about 80 turns of AWG 30 enameled or cloth covered wire, contiguously spaced, near one end of the core. With this, use a ~360 pF variable capacitor. If you have a grid dip meter, you can easily find where this is resonant. If you don't, then you have to poke about on the AM dial of a cheap radio, and see where you can tune it. |
elfa, wrote:
All the devices that have been described by you draw the magnetic component of the radio wave out of the air, and concentrate it in a core that has a coil mounted on it. This induces RF voltage in the coil. In most of these, that coil is connected to a variable capacitor. Both the coil and the capacitor have a property called reactance, which resists the flow of RF current. But the two components have reactances of opposite signs (one positive, one negative), so when you adjust things so the positive & negative numbers are equal at your frequency of interest, the reactances cancel, and a large RF current flows. While this does bring in one more control, the ability to 'peak' the coil to work best ay only one frequency is usually worth it. The trick to using this to boost reception is to have a coil that intercepts more energy than your naked radio does. Ferrite has a high permitivity (take my word for it), which causes the magnetic field that would have flowed near the rod to go through it; the rod picks up energy from a physical space larger than the rod. Another approach is to build an air-core coil that encloses a lot of area. This gives up compactness, but is well-suited to home construction with balsa & plastic. Unfortunately, another poster was right, unless you can give us some quantative data about your rod & capacitor, we can't help with a recommended turns count. To try a guess, start with 40 turns, tune through your frequencies while tuning your loop's capacitor. When you find a frequency where the capacitor can peak the signal (orthe noise), adjust things: remove turns to move the loop's range to higher frequencies, add to bring down. Good luck. -- R F Wieland Newark, DE 19711-5323 USA 39.68N 75.74W Icom R75 Heathkit GR-81 Inverted-L in the attic Reply to wieland at me dot udel dot edu |
You should look at:
http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html (many simple schematics for buling crystal radios are also avaible over WWW pages) elfa wrote: I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
Looked this over; utterly worthless without advanced math skills;
- Good for those what got em ! Subject: Homemade AM ferrite antenna question From: Igor Gros Date: 11/4/2003 3:05 AM Eastern Standard Time Message-id: You should look at: http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html (many simple schematics for buling crystal radios are also avaible over WWW pages) elfa wrote: I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
Try 40 turns of wirewrap wire on the following ferrite:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=30573159 10 I measure 147uH which will put you in the center of the MW band with a 150 pF cap. This means that you can use the standard 10 - 356 pF variable cap. Happy winding, /Dave "Soames123" wrote in message ... Looked this over; utterly worthless without advanced math skills; - Good for those what got em ! Subject: Homemade AM ferrite antenna question From: Igor Gros Date: 11/4/2003 3:05 AM Eastern Standard Time Message-id: You should look at: http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html (many simple schematics for buling crystal radios are also avaible over WWW pages) elfa wrote: I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
Try 40 turns of wirewrap wire on the following ferrite:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=30573159 10 I measure 147uH which will put you in the center of the MW band with a 150 pF cap. This means that you can use the standard 10 - 356 pF variable cap. Happy winding, /Dave "Soames123" wrote in message ... Looked this over; utterly worthless without advanced math skills; - Good for those what got em ! Subject: Homemade AM ferrite antenna question From: Igor Gros Date: 11/4/2003 3:05 AM Eastern Standard Time Message-id: You should look at: http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html (many simple schematics for buling crystal radios are also avaible over WWW pages) elfa wrote: I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
Try 40 turns of wirewrap wire on the following ferrite:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=30573159 10 I measure 147uH which will put you in the center of the MW band with a 150 pF cap. This means that you can use the standard 10 - 356 pF variable cap. Happy winding, /Dave "Soames123" wrote in message ... Looked this over; utterly worthless without advanced math skills; - Good for those what got em ! Subject: Homemade AM ferrite antenna question From: Igor Gros Date: 11/4/2003 3:05 AM Eastern Standard Time Message-id: You should look at: http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html (many simple schematics for buling crystal radios are also avaible over WWW pages) elfa wrote: I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
Try 40 turns of wirewrap wire on the following ferrite:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=30573159 10 I measure 147uH which will put you in the center of the MW band with a 150 pF cap. This means that you can use the standard 10 - 356 pF variable cap. Happy winding, /Dave "Soames123" wrote in message ... Looked this over; utterly worthless without advanced math skills; - Good for those what got em ! Subject: Homemade AM ferrite antenna question From: Igor Gros Date: 11/4/2003 3:05 AM Eastern Standard Time Message-id: You should look at: http://www.st-andrews.ac.uk/~www_pa/...rt7/page5.html (many simple schematics for buling crystal radios are also avaible over WWW pages) elfa wrote: I want to try to make a homemade ferrite antenna to improve the AM reception on an old radio. I can't find any place on the internet that gives a simple explanation of the how to's. All I want to know is how many winds of copper wire and what lead connects to what radio connection. And also, just the most basic of antenna principals involved. Anyone have any suggestions? thanks elfa |
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