Connect with us

Adding Frequency Scanning to any AM/FM/SW Radio

Discussion in 'General Electronics Discussion' started by bigkim100, Apr 22, 2021.

Scroll to continue with content
  1. bigkim100

    bigkim100

    196
    19
    Apr 17, 2013
    I need a circuit that can be added to any recent AM/FM/SW Radio. It should allow the scanning speed to be variable, as well as reversing the scanning (highest to lowest/lowest to highest). Any ideas?
    Thanks in advance:confused:
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    12,455
    2,985
    Nov 17, 2011
    I think you will be hard pressed to find a circuit that can be attached to any radio.
    It may be possible to do so for any specific radio if you know how the tuning is done. You may then be able to control the tuner automatically to create a scanner.
    But there are many ways to implement the tuning circuit:
    - dedicated all-in-one radio ics
    - microcontroller controlled tuners
    - evne SDR (software defined radio) using undersampling and digital signal processing
    - ...
    Each will require a method of its own to create the scanner.
     
  3. bigkim100

    bigkim100

    196
    19
    Apr 17, 2013
    ok, so lets say that I used either a dedicated IC, how would I do this?

    or a specific, variable capacitor tuned radio
     
    Last edited by a moderator: Apr 23, 2021
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    12,455
    2,985
    Nov 17, 2011
    It will depend on the radio you want to modify.
    I don't know of a dedicated "scanner chip". You'll have to whip up a microcontroller and software to create the necessary control signals to tune through the various bands. These control signals may be analog voltages, digital codes, or whatever the tuner requires to set it to a specified frequency.
     
    Last edited: Apr 23, 2021
  5. 73's de Edd

    73's de Edd

    3,350
    1,403
    Aug 21, 2015
    Sir bigkim100 . . . . .


    What is the purpose ?/ end use ? of this type of receiver ?

    Or to " borry" his "sope" box and then mount and stand upon and quote our most honnable and esteemed hevans1944 and emote . . . .quote . . . . .
    Just cut the chase and TELL us what the HECK your FINAL end accomplishments use is being ! . .end quote . . . . . . . .then wipe off his box and return it.

    I initially might only be able to perceive of its use by a long hauler truck driver, with a dedicated concern for safety.
    (OR use by a quadraplegic invalid.)

    The only scanning IC that comes to my mind is a minumalistic design FM scanning IC **** . . . . .TDA7088T . . . . that only scans in one direction and repeats at the very end , BUT, you are being totally blind, as it has no provisions to display the received station ID /or/ frequency.
    It found mass utilization in small clip on FM receivers that fed its audio into an earphone . . . . . they eventually found themselves finally being marketed in . . . . .Just a Dollar Stores.

    ****Also, just for FM only, there is ON semiconductors LV24250LS, but to use that chip complexity, you would need to have electronic and digital design super expertise being entwined within the genetic make up of your one BIG set of gonads.
    Or
    The other item is just merely using / buying one of the past and / or present AM/FM car radio receivers that have an up and down scanning pushbutton, as well as an additional selectable menu of memory preset frequencies.
    But SCRATCH that ADDITIONAL burden of SW radio spectrum ( mostly dead quiet nowadays, anyhow )capability !

    Thaaaaaasssit . . . . . . .

    73's de Edd [​IMG]


    Kids today don't know how easy they have it.
    Why when I was young, I had to walk 9 feet through thick shag carpet just to change the TV channel.


    .
     
  6. hevans1944

    hevans1944 Hop - AC8NS

    4,704
    2,203
    Jun 21, 2012
    When I was young, I had to crawl 9 feet over a bare, highly waxed, floor just to turn the television ON! We had no need to change the TV channel because there was only one channel that the "rabbit ears" antenna, sitting in its glorious place on top of our Hoffman Easy Vision monochrome yellow-green phosphor TV, would receive.

    But that was okay with me because that channel had the Howdy Doody Show on every afternoon... and if you sat realllllly close to the screen you could just about make out (identify) the puppets on the show and distinguish Clarabell from Buffalo Bob. Fun times back in the 20th century.

    I happen to have an amateur radio rig, an Elecraft KX3, that has raw quadrature audio outputs. These two relatively wide-band signals can be processed to visually reveal a frequency spectrum in a "waterfall" display of the band I am operating on, but I haven't done that yet. This sort of thing is a very narrow niche market, often only pursued by avid DX (distance) operators to find openings in the band when a rare station pops up. It is doubtful anyone will offer it as a "feature" on anything other than an amateur radio rig.

    Professional use of a spectrum analyzer analyzer is another story, but very few amateur radio operators can afford a real spectrum analyzer. Some of these expensive puppies can almost display a DC to Light wavelength spectrum, more or less in real time. Just kidding. You still need optics, like a grating or a prism, for a visible-light spectrogram. And some really fancy stuff is required for longer wavelengths, like infrared and terrahertz back-scatter radar imaging.
     
  7. bigkim100

    bigkim100

    196
    19
    Apr 17, 2013
    I would like to adapt standard AM/FM radios with a circuit that sweeps the radio thru either the AM or FM band (Depending on if the radio is in the AM or FM mode). The speed of the sweep needs to be adjustable, and needs to be able to be added to most solid state radios. The attatched filehas been sent to me, but I dont understand how it works.
    Whatcha think?
    Thanks in advance
     

    Attached Files:

  8. Audioguru

    Audioguru

    3,616
    763
    Sep 24, 2016
    Very few radios are tuned with the variable voltage from that circuit.
    Why do you want to sweep the tuned frequencies anyway? The sweep circuit does not not "scan then stop at the next station" that a few radios have.
     
  9. bigkim100

    bigkim100

    196
    19
    Apr 17, 2013
    I do not want it to stop at stations at all

    Can I add Variactor tuning to a radio with standard Variable Capacitor circuits
     
    Last edited by a moderator: May 12, 2021
  10. Audioguru

    Audioguru

    3,616
    763
    Sep 24, 2016
    Where will you find a radio that has voltage tuning?
    Where inside the radio will you connect the voltage sweeping circuit?
    Why do you or anybody want a radio that sweeps all stations in a radio band?
     
  11. bigkim100

    bigkim100

    196
    19
    Apr 17, 2013
    Ok, I was hoping someone who will help me with replacing the standard tuning capacitors with Variactors
     
  12. Harald Kapp

    Harald Kapp Moderator Moderator

    12,455
    2,985
    Nov 17, 2011
    @bigkim100 : I moved the last 5 posts from your newly created separate thread into this one. It is the same topic. Please stay within this thread.
    If the standard capacitors are fixed, they are not used for tuning. Therefore replacing them by Varicaps will help nothing with your scanner. To modify an existing radio you need to find the tunable element.
     
  13. Ylli

    Ylli

    368
    107
    Jun 19, 2018
    I think he is trying to create a "Spirit Box".
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-