Will UHF TV transmit signal may affect our AM radio receive.

Discussion in 'Wireless & RF Design' started by ken_urriquia, Oct 26, 2010.

  1. ken_urriquia

    Thread Starter New Member

    Oct 25, 2010
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    Hello,

    We are receiving then rebroadcast AM radio on our site, and we are starting to transmit our UHF TV signal this coming month. Will our UHF transmit may affect our received signal on AM radio? Please note that the antenna for AM receive is also located on the same tower with antenna for UHF transmit

    Thanks...
     
  2. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    1,758
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    Do you not have an Engineer onhand? How did you get a broadcast license?
     
  3. Papabravo

    Expert

    Feb 24, 2006
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    A strong transmitter will desensitize a a nearby receiver even if the receiver and transmitter are on different frequencies. Weak signals can drop below the raised noise floor in the receiver.
     
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  4. ken_urriquia

    Thread Starter New Member

    Oct 25, 2010
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    Sir,

    Do this mean, there is a possibility that we will no longer receive the AM radio signal once we started to broadcast our UHF TV signal?
     
  5. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Mammamia!!!!!!!!

    Transmitting with no knowledge on radio and TV transmission theory.
    What is this world coming to?
     
  6. ken_urriquia

    Thread Starter New Member

    Oct 25, 2010
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    Sir,

    There are senior engineers who are facilitating the transmission I just want to do some research and learn some basics.

    Thanks.
     
  7. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    Did you ask the senior engineers? What did they say?
     
  8. ken_urriquia

    Thread Starter New Member

    Oct 25, 2010
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    Not yet I'm doing some research before asking them to prevent non sense question that I think what happen on this post. Hehehehehe.
     
  9. Papabravo

    Expert

    Feb 24, 2006
    10,135
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    That is exactly what can happen. Without the UHF TV signal the weak AM signal is just above the noise floor and the receiver can pick it out of the mud -- so to speak. Then the strong EM field from the UHF TV transmitter will raise the noise floor of the AM receiver so that the weak signal is no longer able to make it through the first stage of the receiver and as a result the receiver becomes deaf to weak signals, but can still receive stronger signals. Google "Receiver Desensitization" for more information.

    http://www.lbagroup.com/associates/intfaq.php

    scroll about 2/3 rds of the way down the page.
     
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  10. skeptic

    Active Member

    Mar 7, 2010
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    If your site is well designed the UHF should not affect the reception of AM. Is your site operating as a repeater for AM. I presume you are retransmitting on a different frequency than you receive. I would expect much more interference from the retransmitted AM than the UHF signal.
     
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  11. ken_urriquia

    Thread Starter New Member

    Oct 25, 2010
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    Do this mean there will be no desensitization interference on our AM receiver like what papabravo said if the UHF transmitter system is designed properly?

    "[SIZE=-1]Receiver desensitization interference occurs when an undesired signal from a nearby "off-frequency" transmitter is sufficiently close to a receiver's operating frequency"

    Is there any equipments/shielding needed to install to make this AM/UHF system work without interfering with each other?
    [/SIZE]
     
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