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Thread: M7100 Mobile - Is is capable of Monitoring P25 Trunking in 700 MHz Band

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    Default M7100 Mobile - Is is capable of Monitoring P25 Trunking in 700 MHz Band

    I have an M7100 mobile which I would like to set up to passively monitor a P25 Phase 1 Trunking System (of which I'm an authorized user).
    The radio has the following details:


    M7100 800 MHz
    Model: MAHG-N8MXX

    Radio Software File Name: J2R18L04
    Adi/DSP Software File Name: F8R06S03

    Features: 01 03 04 05 06 07 08 09 10 12 23 33 39


    I looked up the frequency information for the trunking system and noticed that it's on the 700 MHz band (i.e. control channels on 770 MHz),
    which unfortunately are out of the M7100's 806-870 MHz (TX 806-825 MHz, RX 851-870 MHz) frequency ranges.


    I've seen an SC4 file to convert an 800 Band Orion to the 900 MHz amateur band by shifting the RX base up ~50 MHz from 851 MHz to 902 MHz
    and the TX base up ~100 MHz from 802 MHz to 902 MHz.

    My questions for the experts: if I were to craft an SC4 file to lower the RX base down ~80-90 MHz from 851 MHz to ~770 MHz,

    1) Would the radio be able to receive around the 770 MHz frequencies? and

    2) Would the SC4 file adjust all of the various frequencies entered into the trunking sections of the RPM (version RPM10B07) software?


    -RF


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    No, it will not work in the 700mhz band at all. VCO will unlock. Look for an M7200 or a cheap 700/800 XTL.

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    triptolemus (Apr 01, 2019)

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    ADOJA,


    Thank you for your reply. I have a P7200 which I recently purchased from eBay and is my backup plan. I'll at a minimum need to build a programming cable (which is on my to-do list anyways) and probably will need to downgrade the firmware per the discussion in a different thread. I have an XTS5000 which I'll check into using as well, but wanted to go with the M/A-Com/Harris radio as it has the direct ability for passive receive only operation.



    -RF

    P.S. I like your picture of the red MT500. I have one of those in my Motorola radio collection. I just saw one listed on eBay today (not mine) if anyone is interested in getting one.

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    Yes, the P7200 is definitely your best option since it is 700 and 800 (instead of just 800 like the M7100) The programming cable can be built with a $1 FT232RL chip from eBay and a couple extra speaker mic connectors. Or, you can make your own plastic pin holder and get some pins on eBay.

    I have a few P7200's and they're great for listening to P25 trunked and analog EDACS systems. Programming is much easier than my XTS. My Unication G5 does have a little better audio, but price is significantly higher.

    The red MT500 is in like new condition and still works. I wish I could find a yellow one for a reasonable price to match it.

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    The M7200 and P7200 were the first Harris (M/A-Com at the time) product to offer 700 MHz.

    The m7300 replaced the M7200 in supporting 700 & 800 MHz.

    The M5300 is a down-featured M7300 (same hardware), but only allows either 700 or 800, not both.
    Gatorbait3014
    Retired Master Two-Way Radio Master Technician & System Engineer (34+ years)

    My goal in life is to become as wonderful as my dog thinks I am.


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    motorola_otaku (Apr 05, 2019)