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vinod chandran

Jun 21, 2011
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Hi all,
I am planning to build an FM radio. But i don't want any knobs to tune the radio. Instead of that i want to connect it with a remote control. I know the tuning knob of an FM radio is a variable capacitor. Is there any way to control it with a remote control ?.
 

BobK

Jan 5, 2010
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Modern radios use frequency synthesis instead of a variable capacitor to tune. If you are planning to build a retro radio with a variable air capacitor, I supose you could use a servo to turn it.

Bob
 

davenn

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Sep 5, 2009
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or you could go the really modern way of a SDR radio ( SDR = Software Defined Radio) these projects are all the rage at the moment. the output of which is connected to your computer and the signal is decoded ( demodulated) with software and audio is heard. I had one here for a while from a fellow amateur friend... quite cool


Dave
 

CocaCola

Apr 7, 2012
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or you could go the really modern way of a SDR radio ( SDR = Software Defined Radio) these projects are all the rage at the moment. the output of which is connected to your computer and the signal is decoded ( demodulated) with software and audio is heard. I had one here for a while from a fellow amateur friend... quite cool

Yeah, all the rage because it's cheap, easy and wide open the dongles for the computer are about $20 and you have a the grand pappy of scanners...
 

BobK

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Interesting, I am going to have to look that up!

Bob
 

CocaCola

Apr 7, 2012
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Interesting, I am going to have to look that up!

I picked up a dongle just have not found much time to tinker with it yet...

  • FM: both narrow band and wideband. The former is used on two way radio systems such as emergency services and private radio networks (like couriers and taxis) and UHF CB and the latter is the usual broadcast FM the likes of which you have in the kitchen and car. Aircraft and boats and ships also use narrow band FM which you can use RTLSDR to listen to. The SDR# software can receive both narrowband and wideband FM and the latter do stereo FM too!
  • AM: Most AM transmissions are below the bottom frequency of RTLSDR dongles. You will need a translator (I'll deal with translators soon) to get these frequency bands.
  • Upper/Lower Sideband (USB/LSB). See AM above.
  • CW: Continuous wave for morse code enthusiasts.
  • With GNURadio you can receive and demodulate digital modes such as pagers (POCSAG), ADS-B (aircraft positions), AIS (ship positions), AP25 and TETRA (digital trunk radio) and many others.
  • GPS reception is currently being worked on but should be do-able.
  • Satellite reception including receiving ham transmissions from the International Space Station are possible to. I have seen some screen shots of someone using RTLSDR and a 2.5m dish to track the carrier signal on deep space robots such as Voyager and the Mars missions.
  • This post alludes to the tuner chip being disabled and the RTL chip being used to receive transmissions at 30MHz and below.
Lots of fun to be had there for those that want to tinker and snoop... Do note that it might be illegal for you to listen to some of those frequencies depending on your location, but I won't tell...
 
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