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I have a headphone and a cellphone that has built-in FM radio, and the headphone acts as the radio antenna. but my problem is the radio stations I listen to are very far from my place, good thing there are some positions where the sound is very clear.

I have 5 favorite station whom I listen to which are at the same place (that means they're all far from me) and I often switch to each one.

BAD THING is... each station has its OWN position for it to give a clear sound so if I want to switch to another frequency then I need to change the position to another which is very exhausting.

I wanna know if there is still hope to fix this thing.

I listen using the headphone's speaker not in loudspeaker (just saying).

m0Onfang
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  • When talking about different positions, are they all within your flat/house/apartment? Do you have wifi access at this location? – holroy Oct 05 '15 at 22:48

2 Answers2

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Try capacitive coupling to the cell phone: attach a wire about 2 m (6 ft) long to a piece of aluminum foil; rest the plastic case of the phone (avoid any metallic part touching the foil, for safety) on the foil and move the wire around for best reception.

There's no guarantee this will get more stations, but it's an easy experiment. Let us know how it works for you.

DrMoishe Pippik
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  • Can I know what kind of wire should I use? – m0Onfang Oct 10 '15 at 16:49
  • It doesn't make much difference... cheaper thin wire is more easily hidden. – DrMoishe Pippik Oct 11 '15 at 01:26
  • what I mean is, there are many types of wire, which one? could it be electric wire? – m0Onfang Oct 13 '15 at 11:32
  • another thing, do you mean I'll wrap the cellphone with the aluminum foil? – m0Onfang Oct 13 '15 at 11:43
  • Read the answer above. – DrMoishe Pippik Oct 13 '15 at 21:37
  • Would this work for WiFi? – busukxuan Sep 24 '16 at 15:01
  • @busukxuan: For wifi probably not because wavelength is much shorter. –  Sep 25 '16 at 05:07
  • @resident_heretic Is that because the waves can't easily diffract and figuratively get "sucked" into the wire antenna? Then would using an aluminium foil as the antenna work? – busukxuan Sep 25 '16 at 05:10
  • The ideal length of antenna for receiving or transmitting a signal is 1/4 wavelength . For FM (100MHz) approx 750mm or 29.5 inches. For WiFi (2400 Mhz give or take) 31.25mm or 1.25 inches. In order to work efficiently antennas have to electrically resonate . It is somewhat complicated to explain. Where the antenna is connected the radio the voltage induced by the radio signal is at it lowest value and the current is induced is at its highest value. ....I told you it was complicated :) –  Sep 25 '16 at 05:43
  • To complicate it more, the input stage of a radio may have a series inductor, which makes an antenna effectively longer. BTW, for WiFi, you can make an efficient "cantenna" out of a juice can and some wire -- be sure which band you use, as dimensions differ from 2.4 GHz through 5.9 GHz. http://jacobsalmela.com/wi-fi-cantenna-2-4ghz-how-to-make-a-long-range-wi-fi-antenna/ and http://www.turnpoint.net/wireless/cantennahowto.html – DrMoishe Pippik Sep 25 '16 at 17:48
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Signals on the FM(VHF) band are largely line of sight. They are also in a frequency band where nearby metal objects can interfere with the reception of signal due to partial or complete reflection of another signal on the same frequency. FM receivers are also affected by something referred to as capture effect. If your receivers has two signals of similar signal strengths by a certain number of Db(decibels) it will accept the stronger one and reject the weaker one. VHF and UHF signal reception can also be affected by the weather.

FM broadcast signal are reliable generally for about 80KMs or so. The weird thing about FM reception is when you are in a dead spot, simply moving a little bit to the right or left can make quite a difference.