Test, lab, industrial electronic products

How make TV signal strength meter?

I occasionally have need of a TV signal strength meter, when I re-arrange
or debug my TV antenna farm.  (We don’t believe in cable.)

Do any of you either know of a source for an inexpensive signal strength
meter (tunable to individual VHF channels, at a minimum), or can you
suggest a simple way to build one.  I imagine that a tv tuner connected,
to a simple detector to turn the output to DC, connected to a meter,
is the basic idea.

Bill Dudley
wdud…@monmouth.com

posted by admin in Uncategorized and have Comments (3)

3 Responses to “How make TV signal strength meter?”

  1. admin says:

    William F. Dudley (wdud…@shell.monmouth.com) wrote:
    : I occasionally have need of a TV signal strength meter, when I re-arrange
    : or debug my TV antenna farm.  (We don’t believe in cable.)

    : Do any of you either know of a source for an inexpensive signal strength
    : meter (tunable to individual VHF channels, at a minimum), or can you
    : suggest a simple way to build one.  I imagine that a tv tuner connected,
    : to a simple detector to turn the output to DC, connected to a meter,
    : is the basic idea.

    How about simply connecting a voltmeter to the AGC voltage of a TV set?
    That would have the advantage that you’d be able to see the signal
    you’re measuring.  

    AGC is one of the connection points to the tuner, if I’m not mistaken.


    Michael A. Covington                http://www.ai.uga.edu/faculty/covington/
    Artificial Intelligence Center                                           <><
    The University of Georgia                Unless specifically indicated, I am
    Athens, GA 30602-7415 U.S.A.                not speaking for the University.

  2. admin says:

    wdud…@shell.monmouth.com (William F. Dudley) wrote:

    >I occasionally have need of a TV signal strength meter, when I re-arrange
    >or debug my TV antenna farm.  (We don’t believe in cable.)
    >Do any of you either know of a source for an inexpensive signal strength
    >meter (tunable to individual VHF channels, at a minimum), or can you
    >suggest a simple way to build one.  I imagine that a tv tuner connected,
    >to a simple detector to turn the output to DC, connected to a meter,
    >is the basic idea.
    >Bill Dudley
    >wdud…@monmouth.com

    1.      Get a schematic of a TV set you own, but don’t mind breaking.
    Find the AGC line, and run it to a voltmeter.  A VTVM, or DMM is ok.
    That is cheap.  It is easy.  It will work.

    2.      Get an expensive radio that tunes up to 690 MHz and has a
    signal strength meter.

    3.      Get a used, less expensive signal strength meter from a cable
    company.  It won’t cover the upper UHF channels, but it will be
    calibrated, sort of.  Read out will be in dB above or below one
    millivolt.

    4.      Get a new expensive one of the above in No. 3.

            In general, keep your antennas at least one wave length from any other
    antenna.  Keep the antenna at least 1/2 wavelength from other metal,
    except the mounting mast.  Most people don’t keep ‘em far enough
    apart.

    Jeremy  Lansman
    KYES-TV

  3. admin says:

    - Hide quoted text — Show quoted text -

    mcovi…@ai.uga.edu (Michael Covington) wrote:
    >William F. Dudley (wdud…@shell.monmouth.com) wrote:
    >: I occasionally have need of a TV signal strength meter, when I re-arrange
    >: or debug my TV antenna farm.  (We don’t believe in cable.)
    >: Do any of you either know of a source for an inexpensive signal strength
    >: meter (tunable to individual VHF channels, at a minimum), or can you
    >: suggest a simple way to build one.  I imagine that a tv tuner connected,
    >: to a simple detector to turn the output to DC, connected to a meter,
    >: is the basic idea.
    >How about simply connecting a voltmeter to the AGC voltage of a TV set?
    >That would have the advantage that you’d be able to see the signal
    >you’re measuring.  
    >AGC is one of the connection points to the tuner, if I’m not mistaken.
    >–
    >Michael A. Covington                http://www.ai.uga.edu/faculty/covington/
    >Artificial Intelligence Center                                           <><
    >The University of Georgia                Unless specifically indicated, I am
    >Athens, GA 30602-7415 U.S.A.                not speaking for the University.

    I have connected a 50 microamps meter  with a variable resistor in
    series to de AGC of anTV set and it works. But may not give any
    indication  for low signals if the TV set has a so called delayed AGC.
    This is the most commum situation.
    Have fun

    Mel at:      lo…@odyssee.net