Confused about Radio Waves, which can diffract and which can't? Watch

blobbybill
Badges: 11
Rep:
?
#1
Report Thread starter 3 years ago
#1
In my CGP guide, it says: "Radio waves used for TV and FM radio transmissions have very short wavelengths (10cm-10m). To get reception, you must be in direct sight of the transmitter - the signal doesn't bend around hills or travel far through buildings."

Whereas, the BBC website says this:"Radio waves are used to transmit television and radio programmes. Television uses higher frequencies than radio.A radio programme receiver does not need to be directly in view of the transmitter to receive programme signals. Diffraction allows low-frequency radio waves to be received behind hills, although repeater stations are often used to improve the quality of the signals."I am so confused; I get that long wavelength waves are diffracted and short wavelengths or not, but these two articles seem to have contrasting statements.The CGP one sasys that for radio and tv you need to be in sight of the transmitter, but the bbc one says that you dont need to be in sight of it for tv and radio.Can someone explain it properly please?
0
reply
thefatone
Badges: 6
Rep:
?
#2
Report 3 years ago
#2
(Original post by blobbybill)
In my CGP guide, it says: "Radio waves used for TV and FM radio transmissions have very short wavelengths (10cm-10m). To get reception, you must be in direct sight of the transmitter - the signal doesn't bend around hills or travel far through buildings."

Whereas, the BBC website says this:"Radio waves are used to transmit television and radio programmes. Television uses higher frequencies than radio.A radio programme receiver does not need to be directly in view of the transmitter to receive programme signals. Diffraction allows low-frequency radio waves to be received behind hills, although repeater stations are often used to improve the quality of the signals."I am so confused; I get that long wavelength waves are diffracted and short wavelengths or not, but these two articles seem to have contrasting statements.The CGP one sasys that for radio and tv you need to be in sight of the transmitter, but the bbc one says that you dont need to be in sight of it for tv and radio.Can someone explain it properly please?
some waves diffract less than others

1
reply
blobbybill
Badges: 11
Rep:
?
#3
Report Thread starter 3 years ago
#3
but do the radio/tv waves require you to be inline with the receiver or not? One says you do, one says you dont.
(Original post by thefatone)
some waves diffract less than others

0
reply
thefatone
Badges: 6
Rep:
?
#4
Report 3 years ago
#4
(Original post by blobbybill)
but do the radio/tv waves require you to be inline with the receiver or not? One says you do, one says you dont.
i think the diagram answers that, see the(diagram on the right) one with a longer wavelength diffracts more? that doesn't need to be inline with the receiver since it bends round corner and stuff more.
a shorter wavelength however (diagram on the left) diffracts less and can't reach the reciever so the shorter the wavelength, the less if diffracts, the more it needs to be inline with the reciever
0
reply
blobbybill
Badges: 11
Rep:
?
#5
Report Thread starter 3 years ago
#5
(Original post by thefatone)
i think the diagram answers that, see the(diagram on the right) one with a longer wavelength diffracts more? that doesn't need to be inline with the receiver since it bends round corner and stuff more.
a shorter wavelength however (diagram on the left) diffracts less and can't reach the reciever so the shorter the wavelength, the less if diffracts, the more it needs to be inline with the reciever
Yes, and your diagram confirms that. I am asking for with radio waves that are used for TV and FM radio, are they long enough wavelengths to diffract? The CGP says that they are not, whereas the BBC says that they are.

Thanks
0
reply
thefatone
Badges: 6
Rep:
?
#6
Report 3 years ago
#6
(Original post by blobbybill)
Yes, and your diagram confirms that. I am asking for with radio waves that are used for TV and FM radio, are they long enough wavelengths to diffract? The CGP says that they are not, whereas the BBC says that they are.

Thanks


maybe this helps?
0
reply
Joinedup
Badges: 20
Rep:
?
#7
Report 3 years ago
#7
It's not a case of this wave diffracts and that wave doesn't... it's that this (AM radio frequency) wave diffracts more than that (TV frequency) wave

typical AM radio frequency 1.152 MHz ~ 261 m wavelength
typical TV frequency 500 Mhz ~ 0.6 m wavelength

The BBC website is probably written for a less technical audience and is therefore less careful about its terms
1
reply
Kyx
Badges: 6
Rep:
?
#8
Report 3 years ago
#8
(Original post by Joinedup)
It's not a case of this wave diffracts and that wave doesn't... it's that this (AM radio frequency) wave diffracts more than that (TV frequency) wave

typical AM radio frequency 1.152 MHz ~ 261 m wavelength
typical TV frequency 500 Mhz ~ 0.6 m wavelength

The BBC website is probably written for a less technical audience and is therefore less careful about its terms
Not probably, definitely.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • University of West London
    Postgraduate Open Day - Ealing Site Postgraduate
    Thu, 20 Jun '19
  • University of Warwick
    Undergraduate Open Day Undergraduate
    Fri, 21 Jun '19
  • University of Bath
    Find out about life at the University and discover our diverse range of Undergraduate courses. Our course areas include the Sciences, Humanities & Social Sciences, Engineering & Design, and Management. Undergraduate
    Fri, 21 Jun '19

How did your AQA A-level Chemistry Paper 3 go?

Loved the paper - Feeling positive (48)
29.27%
The paper was reasonable (83)
50.61%
Not feeling great about that exam... (17)
10.37%
It was TERRIBLE (16)
9.76%

Watched Threads

View All