@vertigoandblastoise I am not sure how 2 loops would work, but I do know that a larger loop will work better, I have played around with a few other sizes and the larger ones do seem to work better.
can you stretch the frequency coverage up to cover the 160m band? (1800-2000khz) i would like it to cover 500/530-2000khz. is this possible with a 365pF cap or will it take more capacitance? (500pF)??
@quarknimble I am not sure if you would be able to stretch it out that far or not but I just added a link to the page I used to calculate my dimensions, you can play around with it putting in different values to see where you come out.
@quarknimble you can adjust the frequency coverage either by adding/removing capacitance or by varying the number of turns of wire. So, to cover 160m you would need to reduce the capacitance (eg. by adding a fixed capacitor in series with the variable capacitor) or remove some turns of wire. If you want, you can use a switch to add/remove fixed capacitors from the circuit to extend the overall range.
@miketmac yes it does, I just added a link in my video description that you can use to calculate the dimensions needed. You can play around with the calculator plugging in different frequencies etc using what you have to figure things out, works well.
@miketmac yes, the number of turns will affect the inductance of the loop and hence its resonant frequency. Add more turns to lower the range of frequencies covered. The size of the wire also impacts inductance (thinner wire increases inductance), but also affects the "Q" (selectivity) of the loop. Thinner wire increases the overall loop resistance, therefore lowers the Q, and so makes the loop less selective and less efficient.
@miketmac I had a few in my parts box salvaged from old AM radios, 365 pico-farad is the value I used. There are several places that sell them also, just search for 365 pico-farad variable capacitor in the search engine and you will find places you can buy them new. I don't think Radio Shack sells them these days.
@FarceTheory a single turn loop can be made for FM frequencies but you would probably be better off with a dipole or beam style antenna for FM frequencies mounted outdoors. This AM band loop would not work on the FM band since it is designed for much lower frequencies...
@Ibringthetruth1 generally these AM radios do have a loop antenna inside. In order to keep it small, they use a stick of ferrite to wind the antenna around. However, the efficiency of a loop antenna depends on the diameter of the loop, and which is why this big external antenna works so much better than the built-in loop antenna alone.
And a word to the wise... you just can't use a random number and size of wire turns, or just any variable capacitor. Together the coil and the capacitor form a tuned LC circuit at a frequency determined by the combined values of the coil and capacitor. Both values have to be calculated to place the tuned circuit to cover 560-1720khz... the AM band. You can copy a known working design... as in this case, or use the formulas to calculate those LC values.
I made one, but mounted it on the wall of a bedroom (I knew the direction of the distant station I wanted). Mine is 36" (three feet) measured diagonally with 11-turns of 30-ga wire in a 1.1" coil. I use an el-cheapo solid-state variable capacitor to tune mine, and built a sturdy shelf on the wall in the middle of the loop to place my radio.
I'm not sure where a ferrite rod could be placed.
I am a big AM/MW fan -m I am considering buying a grundig satelitt 750 mainly because of the turnable ferrite rod antenna on top - do you think a second larger or longer ferrit ros glued or taped on top would improve reception further? I want to be able to listen to Chicago radio in Florida- your loop looks fine but a ferrite rod would be less cumbersome- is there any way to put a plug on your loop so it could set a few feet away from the radio and still work or is it near-field only?
@opolo2112 I think the rod antenna that radio has will work very well and I don't think the antenna in the video will work much better since that radio and ferrite should work very well the way it is. My loop will mainly improve radios of less quality than that one. However, if you were to make a much larger sized loop than mine you may notice a good improvement. You can hook up any loop directly to the radio if there is an external jack for AM but I have not tried that yet.
Ferrite rod booster would be great for this purpose. I use mine from Houston to listen to 670, 720, 780, and 890 kHz stations on my 750--look at Youtube video (locate via "ferrite rod antenna" search term). Let me know if i can help further!
@kenlen13 Yes, a medium wave radio. The older tube types have the large open air capacitor and I like those the best but you can also use the small mini sized variable tuning caps found in transistor radios and that should be fine also. Antique Electronic Supply (search name) has the open air type 365pf, part number C-V365 I see for around 12 bucks. They probably have the small plastic enclosed ones also but not sure.
@johnu78 I don't remember the guage for sure but it was just some small wire I had around on a spool. The size of the wire is not that critical, the smaller wire is easy to get several turns than with a larger wire but I wouldn't worry too much as long as it is easy to work with.
@johnu78 Also, I used insulated wire so the wires would not short out to each other, you do need to keep each turn separate from the others so as not to short out to each other or it will not work for the range you want.
My loop antenna covers from 650 to 1710khz. Because i put 5mm separation from one turn to another. Same loop as the video (30x15cm of wood), and I used a variable capacitor of 336pf
It is directional, but your signal is in the direction that the cross is facing. Signals pass in the center of the loop, not along the perimeter. But otherwise good job.
great vid!!! Im very new to this .I just pick up an old am radio from 1938 Silvertone #4569.Need an antanna this look antanna looks great.the radio has short wave as well.The ? is will it work on short wave as well?Im thinking a longwave antanna as well.Oh what is the gauge wire did you you use and the lenght.thxs again for very cool vid.any help would be very helpfull thxs again
@bennra26008 thanks for the comment! That is great on the Silvertone, you will have a lot of fun with that radio. The loop I made will only work on the AM broadcast band, but you can make a loop that will cover parts of the shortwave band if you wanted but a whip antenna or wire antenna should work fine for you on SW. If you google loop antennas you will find a lot of info for other bands though if you want. I think I used 20gauge wire or so, not critical at all, small wire is easy to use.
@josephdupont Guess I should have, lol. I just had it set to the pre-tuned station at the time and didn't really think about it at the time for some reason. Thanks for the comment.
Hi, thanks for the video. I'm new to this and curious, i'm guessing that the size of the structure is relative to the number of turns. Also how do you know which connection on the capacitor is negative and do you just solder the other end to the housing. Thanks!!!
@mrjon925 Thanks for the comment, you are correct, the larger the size, the less number of turns needed. There are online calculators if you do a google search for calculating am radio loop antenna that will give you number of turns to use with your capacitor and size you want, you can experiment with the calculator.Tthe variable cap is not polarity sensitive, Just put in series with the loop wire. Once side of my cap was on the housing but not always the case.
Very interesting and informative video, thanks for sharing on YouTube!
I have a quick question, do you know if there is a design of AM antenna that would be suitable for mounting in a loft-space, away from the tuner? I have a hifi in the living room, and am looking to pull in weak AM and MW signals. I live in the Scottish Highlands. If you have any ideas on what to try, I would love to hear them, thanks!
@Phedrus1975 Thanks for the comment, and yes there is an antenna that might work for you, the only one I am aware of commercially made I guess, and that is the twin coil ferrite from the C.Crane company. I tried to put the link here but looks like that is not allowed, so you will have to search for that at the C.Crane home page.
Hopefully that might work for you...Larry
If anyone else has any more ideas please leave a comment here! thanks
This is really interesting and informative, Thanks for sharing. Do you think the results would be greater if you made the antenna larger? In other words, Say you made it 3 or 4 feet across. Would it pull in stations even stronger?
@DrOlds100 Thanks for the comment and yes, a larger loop would work better, I intend on making a larger one in the future to try out, if I do I will try to post that also on here...I may try something like a hula hoop loop or something about that size.
@djEvilDude I think you can get them online yet if you don't have one, just search for 365 picofarad variable capacitor. No batteries needed, the loop of the wire simply couples with the internal small built in loop the radio has, just like a transformer works, all you need is the wire and the capacitor and place by the radio. Lots of plans on the net if you search for AM radio loop antennas. Thanks for the comment and question also BTW! Always appreciated here.
@Bigus85 There are commercial versions you can buy such as a TERK AM antenna loop, just do a search on that and you will see them, there used to be one called the SELECTENNA I think it was or something like that, not sure if they still make them or not. Or you can make your own, several websites that show you how to do that if you search for Build AM Radio Loop Antenna. They all work about the same as far as I can tell as long as they are made to cover the same frequencies.
Tunable loops are the best for limited space and work VERY well.
John
jstrunck 2 weeks ago
This has been flagged as spam show
Super job on the loop!
Tunable loops are the best for limited space and work VERY well.
John
jstrunck 2 weeks ago
Super job on the loop!
Tunable loops are the best for limited space and work VERY well.
John
jstrunck 2 weeks ago
That works fabulous! I wonder what would happen if you had TWO of that loops.....
I am gonna find out for myself, but does it also matter if you make the loops larger?
Are they more powerfull? Or just two loops to make it more powerfull? thanks!
vertigoandblastoise 3 weeks ago
@vertigoandblastoise I am not sure how 2 loops would work, but I do know that a larger loop will work better, I have played around with a few other sizes and the larger ones do seem to work better.
RadioHamGuy 3 weeks ago
can you stretch the frequency coverage up to cover the 160m band? (1800-2000khz) i would like it to cover 500/530-2000khz. is this possible with a 365pF cap or will it take more capacitance? (500pF)??
quarknimble 1 month ago
@quarknimble I am not sure if you would be able to stretch it out that far or not but I just added a link to the page I used to calculate my dimensions, you can play around with it putting in different values to see where you come out.
RadioHamGuy 3 weeks ago
@quarknimble you can adjust the frequency coverage either by adding/removing capacitance or by varying the number of turns of wire. So, to cover 160m you would need to reduce the capacitance (eg. by adding a fixed capacitor in series with the variable capacitor) or remove some turns of wire. If you want, you can use a switch to add/remove fixed capacitors from the circuit to extend the overall range.
ma3xiu1 3 days ago
does the size of the wire and the turns matter??? thanks for the help!
miketmac 1 month ago
@miketmac yes it does, I just added a link in my video description that you can use to calculate the dimensions needed. You can play around with the calculator plugging in different frequencies etc using what you have to figure things out, works well.
RadioHamGuy 3 weeks ago
@miketmac yes, the number of turns will affect the inductance of the loop and hence its resonant frequency. Add more turns to lower the range of frequencies covered. The size of the wire also impacts inductance (thinner wire increases inductance), but also affects the "Q" (selectivity) of the loop. Thinner wire increases the overall loop resistance, therefore lowers the Q, and so makes the loop less selective and less efficient.
ma3xiu1 3 days ago
@ma3xiu1 Thanks , still trying to find the variable capacitor
miketmac 2 days ago
were you found the capacitor? can i bought it on radio shack? what specs?
miketmac 1 month ago
@miketmac I had a few in my parts box salvaged from old AM radios, 365 pico-farad is the value I used. There are several places that sell them also, just search for 365 pico-farad variable capacitor in the search engine and you will find places you can buy them new. I don't think Radio Shack sells them these days.
RadioHamGuy 3 weeks ago
@RadioHamGuy Thanks
miketmac 3 weeks ago
@RadioHamGuy Building in process
miketmac 3 weeks ago
Can this be done with FM?
FarceTheory 1 month ago
@FarceTheory a single turn loop can be made for FM frequencies but you would probably be better off with a dipole or beam style antenna for FM frequencies mounted outdoors. This AM band loop would not work on the FM band since it is designed for much lower frequencies...
RadioHamGuy 1 month ago
very cool! would be nice to see a "how to build"
natacus2007 2 months ago
you didn't show us anything. You just showed us that it works. You didn't show us how to make it.
BeyondNeptune 6 months ago
Why don't they include a damn loop antenna in the radio or as attachment.
just stupid.
good video.
Ibringthetruth1 6 months ago
@Ibringthetruth1 generally these AM radios do have a loop antenna inside. In order to keep it small, they use a stick of ferrite to wind the antenna around. However, the efficiency of a loop antenna depends on the diameter of the loop, and which is why this big external antenna works so much better than the built-in loop antenna alone.
ma3xiu1 3 days ago
And a word to the wise... you just can't use a random number and size of wire turns, or just any variable capacitor. Together the coil and the capacitor form a tuned LC circuit at a frequency determined by the combined values of the coil and capacitor. Both values have to be calculated to place the tuned circuit to cover 560-1720khz... the AM band. You can copy a known working design... as in this case, or use the formulas to calculate those LC values.
mnpd007 7 months ago
I made one, but mounted it on the wall of a bedroom (I knew the direction of the distant station I wanted). Mine is 36" (three feet) measured diagonally with 11-turns of 30-ga wire in a 1.1" coil. I use an el-cheapo solid-state variable capacitor to tune mine, and built a sturdy shelf on the wall in the middle of the loop to place my radio.
I'm not sure where a ferrite rod could be placed.
mnpd007 7 months ago
@mnpd007 Great to hear!
RadioHamGuy 7 months ago
This has been flagged as spam show
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Auction ends Jun 12, 201114:40:01 PDT
iamIegion 8 months ago
I am a big AM/MW fan -m I am considering buying a grundig satelitt 750 mainly because of the turnable ferrite rod antenna on top - do you think a second larger or longer ferrit ros glued or taped on top would improve reception further? I want to be able to listen to Chicago radio in Florida- your loop looks fine but a ferrite rod would be less cumbersome- is there any way to put a plug on your loop so it could set a few feet away from the radio and still work or is it near-field only?
opolo2112 9 months ago
@opolo2112 I think the rod antenna that radio has will work very well and I don't think the antenna in the video will work much better since that radio and ferrite should work very well the way it is. My loop will mainly improve radios of less quality than that one. However, if you were to make a much larger sized loop than mine you may notice a good improvement. You can hook up any loop directly to the radio if there is an external jack for AM but I have not tried that yet.
RadioHamGuy 9 months ago
@opolo2112
Ferrite rod booster would be great for this purpose. I use mine from Houston to listen to 670, 720, 780, and 890 kHz stations on my 750--look at Youtube video (locate via "ferrite rod antenna" search term). Let me know if i can help further!
salmonguyrep 9 months ago in playlist Amateur / shortwave Radio
what kind of radio can I salvage a variable capacitor from? does it have to come from a radio which tunes only MW? or where can I purchase one?
kenlen13 10 months ago
@kenlen13 Yes, a medium wave radio. The older tube types have the large open air capacitor and I like those the best but you can also use the small mini sized variable tuning caps found in transistor radios and that should be fine also. Antique Electronic Supply (search name) has the open air type 365pf, part number C-V365 I see for around 12 bucks. They probably have the small plastic enclosed ones also but not sure.
RadioHamGuy 10 months ago
What type of wire did you use?
johnu78 10 months ago
@johnu78 I don't remember the guage for sure but it was just some small wire I had around on a spool. The size of the wire is not that critical, the smaller wire is easy to get several turns than with a larger wire but I wouldn't worry too much as long as it is easy to work with.
RadioHamGuy 10 months ago
@johnu78 Also, I used insulated wire so the wires would not short out to each other, you do need to keep each turn separate from the others so as not to short out to each other or it will not work for the range you want.
RadioHamGuy 10 months ago
Does the antenna itself have any power to it?
johnu78 10 months ago
@johnu78 No power needed, it is a passive device, just the loop tuned to the same frequency as the radio.
RadioHamGuy 10 months ago
@RadioHamGuy
Okay. Excellent. What type of wire did you use?
johnu78 10 months ago
@johnu78 22# size .
Srry I forget it
Excellent video and thx for the antenna
renewii 10 months ago
wow great antenna.
My loop antenna covers from 650 to 1710khz. Because i put 5mm separation from one turn to another. Same loop as the video (30x15cm of wood), and I used a variable capacitor of 336pf
renewii 10 months ago
Need a better view of thw way the capacitor is hooked up! Great looking antenna
KC8YOQ 1 year ago
I made the same using Litz wire cause it's much better on mw frequencies
renekenshin6573 1 year ago
It is directional, but your signal is in the direction that the cross is facing. Signals pass in the center of the loop, not along the perimeter. But otherwise good job.
jasonwiener1988 1 year ago
great vid!!! Im very new to this .I just pick up an old am radio from 1938 Silvertone #4569.Need an antanna this look antanna looks great.the radio has short wave as well.The ? is will it work on short wave as well?Im thinking a longwave antanna as well.Oh what is the gauge wire did you you use and the lenght.thxs again for very cool vid.any help would be very helpfull thxs again
bennra26008 1 year ago
@bennra26008 thanks for the comment! That is great on the Silvertone, you will have a lot of fun with that radio. The loop I made will only work on the AM broadcast band, but you can make a loop that will cover parts of the shortwave band if you wanted but a whip antenna or wire antenna should work fine for you on SW. If you google loop antennas you will find a lot of info for other bands though if you want. I think I used 20gauge wire or so, not critical at all, small wire is easy to use.
RadioHamGuy 1 year ago
I've seen enough of these to know that your design is very good.
thanks for your youtube. If more people knew about this they would not need
Sirus.
josephdupont 1 year ago
how come you did not adjust the capacitor? interesting youtube
josephdupont 1 year ago
@josephdupont Guess I should have, lol. I just had it set to the pre-tuned station at the time and didn't really think about it at the time for some reason. Thanks for the comment.
RadioHamGuy 1 year ago
Thanks for the great report! :D
~Cindy, a BIG fan of AM DXing. :)
CindyBradyTooh 1 year ago
@CindyBradyTooh It sure is a fun hobby, I started at age 7 with an AM transistor radio I got for Christmas.
RadioHamGuy 1 year ago
Hi, thanks for the video. I'm new to this and curious, i'm guessing that the size of the structure is relative to the number of turns. Also how do you know which connection on the capacitor is negative and do you just solder the other end to the housing. Thanks!!!
mrjon925 1 year ago
@mrjon925 Thanks for the comment, you are correct, the larger the size, the less number of turns needed. There are online calculators if you do a google search for calculating am radio loop antenna that will give you number of turns to use with your capacitor and size you want, you can experiment with the calculator.Tthe variable cap is not polarity sensitive, Just put in series with the loop wire. Once side of my cap was on the housing but not always the case.
RadioHamGuy 1 year ago
Very interesting and informative video, thanks for sharing on YouTube!
I have a quick question, do you know if there is a design of AM antenna that would be suitable for mounting in a loft-space, away from the tuner? I have a hifi in the living room, and am looking to pull in weak AM and MW signals. I live in the Scottish Highlands. If you have any ideas on what to try, I would love to hear them, thanks!
Phedrus1975 1 year ago
@Phedrus1975 Thanks for the comment, and yes there is an antenna that might work for you, the only one I am aware of commercially made I guess, and that is the twin coil ferrite from the C.Crane company. I tried to put the link here but looks like that is not allowed, so you will have to search for that at the C.Crane home page.
Hopefully that might work for you...Larry
If anyone else has any more ideas please leave a comment here! thanks
RadioHamGuy 1 year ago
@RadioHamGuy Thanks for your reply, I'll look into it!
Phedrus1975 1 year ago
Thanks you sir! From "Next Door"!!! Will make one of these sometime!!
MSTLOM 1 year ago
HI,
This is really interesting and informative, Thanks for sharing. Do you think the results would be greater if you made the antenna larger? In other words, Say you made it 3 or 4 feet across. Would it pull in stations even stronger?
DrOlds100 1 year ago
@DrOlds100 Thanks for the comment and yes, a larger loop would work better, I intend on making a larger one in the future to try out, if I do I will try to post that also on here...I may try something like a hula hoop loop or something about that size.
RadioHamGuy 1 year ago
Awesome, I really want to build one but I don't think I have a capacitor laying around!
Also does it need batteries?
Thanks!
djEvilDude 1 year ago
@djEvilDude I think you can get them online yet if you don't have one, just search for 365 picofarad variable capacitor. No batteries needed, the loop of the wire simply couples with the internal small built in loop the radio has, just like a transformer works, all you need is the wire and the capacitor and place by the radio. Lots of plans on the net if you search for AM radio loop antennas. Thanks for the comment and question also BTW! Always appreciated here.
RadioHamGuy 1 year ago
Where I can buy an antenna like that?
Thanks!
Bigus85 1 year ago
@Bigus85 There are commercial versions you can buy such as a TERK AM antenna loop, just do a search on that and you will see them, there used to be one called the SELECTENNA I think it was or something like that, not sure if they still make them or not. Or you can make your own, several websites that show you how to do that if you search for Build AM Radio Loop Antenna. They all work about the same as far as I can tell as long as they are made to cover the same frequencies.
RadioHamGuy 1 year ago
Oups, I guess You meant 365 pf ...
Alain - VE2CUY
puyansude 1 year ago
Yes I did, sorry, I will have to put a correction there!
RadioHamGuy 1 year ago
impressive loop
burt2481 1 year ago