forum.vdsworld.com Forum Index forum.vdsworld.com
Visit VDSWORLD.com
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 


FM Radio stations using a TV card?

 
Post new topic   Reply to topic    forum.vdsworld.com Forum Index -> Miscellaneous
View previous topic :: View next topic  
Author Message
Mac
Professional Member
Professional Member


Joined: 08 Jul 2000
Posts: 1585
Location: Oklahoma USA

PostPosted: Fri Mar 18, 2005 11:42 pm    Post subject: FM Radio stations using a TV card? Reply with quote

Anyone know if this is possible?

If so, do ya have any ideas how to accomplish it?

I've had FM radios pick up TV stations before, just
wondering if the reverse is true. I'm in the US btw.

Cheers, Mac Smile

_________________
VDSug.dll does file IO, check/disable menu items,
non-VDS dlls, draw functions and more...
Free download (30k dll size) at:
http://www.vdsworld.com/download.php?id=361
Back to top
View user's profile Send private message Send e-mail
FreezingFire
Admin Team


Joined: 23 Jun 2002
Posts: 3508

PostPosted: Sat Mar 19, 2005 2:18 am    Post subject: Reply with quote

AFAIK my TV card can't do such a thing. However, there are small,
inexpensive USB adapters that you can get to recieve FM/AM radio on
your computer. You might want to look into those. Smile

_________________
FreezingFire
VDSWORLD.com
Site Admin Team
Back to top
View user's profile Send private message Visit poster's website
CodeScript
Moderator Team


Joined: 08 Jun 2003
Posts: 1060
Location: India

PostPosted: Sun Mar 20, 2005 9:19 am    Post subject: Reply with quote

I remember to have seen a TV tuner card with built in FM. Dunno which make was it though..
_________________
Regards
- CodeScript
Arrow Give your application a professional look with the VDSGUI Extension
Back to top
View user's profile Send private message Visit poster's website
Hooligan
VDS Developer
VDS Developer


Joined: 28 Oct 2003
Posts: 479
Location: California

PostPosted: Mon Mar 21, 2005 4:38 pm    Post subject: Reply with quote

Now you've touched on an area of my expertise... (worked repairing electronics for years and years.)
In the US, the FM radio band runs from 88 MHz to 108 MHz. The stations must have 0.2 MHZ seperation, and must be centered at odd tenth's (i.e. 88.1MHz, 88.3MHz, 88.5MHz, etc.)
TVs on the other hand, have 6 MHz of seperation between channels, with the sound being centered at 0.25MHz below the top end of its allotted frequency range. Channels 2 through 6 are from 54 MHz to 88 MHz, putting the sound carrier for channel 6 at 87.75 MHz (real close to the bottom end of the FM band). The sound is actually "encoded" onto the carrier differently on TV than FM radio, which means that even if you could tune to the correct frequency, your TV probably wouldn't demodulate the sound effectively. (Actually a low quality TV would probably work better than a high quality TV, for this) Channels 7 through 13 are assigned 174MHz to 216 MHz, well above the FM band. Only a massively overdriven FM station, producing lots of harmonics, and just at the right frequency, would allow picking up the sound at channels in this range. The same goes for channels 14 through 83, in which the frequencies are from 470 MHz to 890 MHz. Other countries have entirely different TV schemes, so the effects would be conciderably different.

Sorry for rambling on, but hopefully that helps you understand some of the basics behind it.

Hooligan

_________________
Hooligan

Why be normal?
Back to top
View user's profile Send private message
Mac
Professional Member
Professional Member


Joined: 08 Jul 2000
Posts: 1585
Location: Oklahoma USA

PostPosted: Mon Mar 21, 2005 11:23 pm    Post subject: Reply with quote

Thanks for the input guys. Smile

Hooligan, I appreciate the info. It's quite possible the
FM radio picking up TV stations was due to a couple
of factors:

1. The radio I remember was a second hand portable
and may have had frequency problems - as I recall it
didn't work for very long.

2. I was within sight of the TV transmitter tower, and
there was a set of those huge cross-country power
lines on property next to us (between us and the TV
tower) that prolly affected (distorted?) the signal we
were getting (US channel 12 btw).

This was several years ago, so I may have tinkered
with the rheostats (and hence the frequencies). I have
some knowledge of electronics (lol, just enough to be
dangerous prolly: "Hey ya'll, watch this..."). Laughing

This was mostly just a curiosity question - I have an
AM/FM/WX radio by the computer anyway. Wink

Thanks again, Mac Smile

_________________
VDSug.dll does file IO, check/disable menu items,
non-VDS dlls, draw functions and more...
Free download (30k dll size) at:
http://www.vdsworld.com/download.php?id=361
Back to top
View user's profile Send private message Send e-mail
Hooligan
VDS Developer
VDS Developer


Joined: 28 Oct 2003
Posts: 479
Location: California

PostPosted: Mon Mar 21, 2005 11:50 pm    Post subject: Reply with quote

Were you tuned to 104.9 or thereabouts? That would be the first subharmonic (half the sound carrier frequency). Although, if the TV station was right on top of you, it could very well bleed over to stations "off-center".
...Fun with RF electronics...

Enjoy...
Hooligan

_________________
Hooligan

Why be normal?
Back to top
View user's profile Send private message
Mac
Professional Member
Professional Member


Joined: 08 Jul 2000
Posts: 1585
Location: Oklahoma USA

PostPosted: Mon Mar 21, 2005 11:53 pm    Post subject: Reply with quote

Hooligan, I just remember it was near one end of
the FM range - don't remember which end. Embarassed

That may very well be the case though. Wink

Cheers, Mac Smile

_________________
VDSug.dll does file IO, check/disable menu items,
non-VDS dlls, draw functions and more...
Free download (30k dll size) at:
http://www.vdsworld.com/download.php?id=361
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    forum.vdsworld.com Forum Index -> Miscellaneous All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum

Twitter@vdsworld       RSS

Powered by phpBB © 2001, 2005 phpBB Group