Results 1 to 11 of 11

Thread: 808 mhz RX on XTL?

  1. #1
    Join Date
    Sep 04, 2012
    Posts
    51
    Thanks
    10
    Thanked 60 Times in 14 Posts

    Default 808 mhz RX on XTL?

    I am trying to track down some illegal carriers and wanted to program the repeater input, around 808mhz, into a XTL or XTS (mixed mode digital CSQ) to try and locate the offending signal. CPS does not like a RX freq in this range and creates an invalid. Anyone know of a work around? I have APX equipment available as well and have not tried to input 808mhz on that CPS, but I suspect the result will be the same.


  2. #2
    Join Date
    Jan 05, 2013
    Location
    Planet Vulcan
    Posts
    189
    Thanks
    144
    Thanked 104 Times in 50 Posts

    Default

    Unfortunately a service monitor is what has been used in past around here due to that issue, but with no real signal strength meter it is kinda worthless. Might be easier using an inexpensive scanner.

  3. #3
    Join Date
    Oct 08, 2012
    Posts
    280
    Thanks
    4
    Thanked 177 Times in 77 Posts

    Default

    A service monitor? No real signal strength meter? You're joking, right?

  4. #4
    cyrus's Avatar
    cyrus is offline Trailer Park Superintendent
    Join Date
    Jan 06, 2012
    Location
    Moonbase Alpha
    Posts
    902
    Thanks
    379
    Thanked 447 Times in 204 Posts
    Country: Japan

    Default

    Try a spectrum analyzer with a directional antenna. It will allow you to characterize the offending signal as well as localizing it.
    Cyrus

    Bubbles: I'd like to see that Red Blue Green c***sucker put one of those together, duct-tapin' it.

  5. #5
    Join Date
    Mar 07, 2013
    Location
    On the road
    Posts
    71
    Thanks
    2
    Thanked 90 Times in 21 Posts
    Country: United States

    Default

    To add to this, I would HIGHLY suggest a bandpass filter also. Most S/A's will overload (mixer saturation) in the vicinity of cell/ESMR sites.

  6. #6
    Join Date
    Mar 07, 2013
    Location
    On the road
    Posts
    71
    Thanks
    2
    Thanked 90 Times in 21 Posts
    Country: United States

    Default

    And since we're on the subject, here's my latest find...

    20130829_134330.jpg

    You'd really be surprised how far 50 mW (supposedly) at 800.750 MHz will go.

  7. #7
    freerider-aust No Longer Registered

    Default

    the info you are after is here https://www.p25.ca/threads/41-HOWTO-...lits%29-in-CPS also the apx bands are set in the firmware so you wont be able to change it

    Quote Originally Posted by kb0uxv View Post
    I am trying to track down some illegal carriers and wanted to program the repeater input, around 808mhz, into a XTL or XTS (mixed mode digital CSQ) to try and locate the offending signal. CPS does not like a RX freq in this range and creates an invalid. Anyone know of a work around? I have APX equipment available as well and have not tried to input 808mhz on that CPS, but I suspect the result will be the same.

  8. #8
    Join Date
    Mar 07, 2013
    Location
    On the road
    Posts
    71
    Thanks
    2
    Thanked 90 Times in 21 Posts
    Country: United States

    Default

    Quote Originally Posted by freerider-aust View Post
    the info you are after is here https://www.p25.ca/threads/41-HOWTO-...lits%29-in-CPS also the apx bands are set in the firmware so you wont be able to change it
    I'm pretty sure the filtering won't pass any 800 MHz reverse link frequencies, even if the CPS hack allows it.

    But I could be wrong.
    Last edited by KevinC; Sep 02, 2013 at 01:28 AM.

  9. #9
    Join Date
    Jan 05, 2013
    Location
    Planet Vulcan
    Posts
    189
    Thanks
    144
    Thanked 104 Times in 50 Posts

    Default

    Quote Originally Posted by tvsjr View Post
    A service monitor? No real signal strength meter? You're joking, right?
    What I meant to say is that the Motorola radio doesn't have a signal strength meter. My bad...the young one broke my train of thought while I was typing.

  10. #10
    Join Date
    Feb 04, 2012
    Posts
    2,048
    Thanks
    257
    Thanked 937 Times in 412 Posts

    Default

    In had a similar problem a while ago what I ended up doing was to take a 800 duplexer and set the one bandpass to the offending freq then I used a uniden BCD996 scanner as the reciever with a scope program on a laptop to look at the signal modulation. I was able to track down the source of interfearance in an hour. The signal meter on the scanner along with the attenuator function served well all that was needed was to change the antenna to a 1/4 wave once I got full scale and remove it completely to finish the location. FYI it turned out to be a european modem used by a "new" resident to the country who had no idea his stuff was not legal here in this country.

    I do have a spectrum analizer and a lot of other test equipment but this all sat on the seat of my car and was easy to look at while driving arround.

    As another FYI Industry Canada was absolutly useless in helping.

  11. #11
    Join Date
    Sep 04, 2012
    Posts
    51
    Thanks
    10
    Thanked 60 Times in 14 Posts

    Default

    Thanks for the replies. I ended up figuring out the issue last night, one of the local shops was doing a PM at a sub-site a week ago and must have accidently reversed the channel bank v.24 cables between channels 7 and 8. I got the big clue last night when monitoring the output freqs with digital CSQ (when you alias the channel names its like zone watch in the field), duplicate audio was on both channels. Swapped the cables and all is now well.