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Thread: Futurecom DVRS Operation

  1. #1
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    Default Futurecom DVRS Operation

    Hey guys, we operate a few DVRS units (16) in our fleet. and just looking for comments one how you guys use/operate yours.

    We migrated from VHF Astro to a 700MHz P25 p2 system, we had DVRS units operating in simplex mode on VHF and now use them on 800 MHz, still simplex... We now have some new frequencies now so I'll be migrating them to duplex sometime this year.

    Currently, our crews in the trucks have to enable the DVRS with a switch wired up the a VIP cable. They occasionally forget, leave the switch on all the time or have all of them turned on at the scene (in simplex can cause issues). Dispatch isn't keen on having to remotely turn them on/off. System coverage is pretty good but admin wants them to be used all the time for anything in-building, although not needed imo.


    Just looking to see what others have found that works or challenges they encountered... Thanks.


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    Default

    One local fire agency has their units wired to the parking brake. Once they arrive on scene and park, the unit automatically enables. They rely on the DVRS Primary/Secondary algorithm to keep things orderly with multiple units on scene, which also has challenges. The DVRS default settings are geared towards single unit use (such as rural Police road stops), which make the units extremely 'deaf' to one another, and need to be changed. I'll post the notes from a tech brief below:

    The following parameters should be adjusted on a DVR to change the Primary/Secondary selection criteria for co-located DVRS scenario.

    1. Busy Lockout Threshold: This threshold is used by the Primary DVR during the dynamic Busy Lockout Phase to determine if another nearby radio (DVR) is already transmitting. This value should be set to minimum (-105dBm).

    2. Rx. RSSI Threshold: This threshold is used by a DVR to determine if another unit (DVR or PSU) is transmitting on the DVR Rx frequency. If a signal above this threshold is detected, DVR will postpone sending of Primary/Secondary messages to ensure proper transmission of these messages. If a Primary DVR is receiving Primary Heart Beat from another DVR at a level lower than the programmed threshold, the DVR will ignore the Primary Heart Beats and stay on in a Primary State. This value should be set to minimum (-110dBm).

    3. Tx. RSSI Threshold: This threshold is used by a non-Primary DVR to determine if another DVR is transmitting on the DVR Tx frequency. If a signal above this threshold is detected, DVR assumes that another DVR is transmitting (repeating call or sending signaling message). This value should be set to minimum (-110dBm).

    4. Rev. Tx Power: This is the Transmit power level at which a DVR transmits on the DVR Rx Frequency to communicate with other DVRs including transmission of Primary Heart Beat to other DVRs. This value should be set to maximum (+39dBm).

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  5. #3
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    Default

    Thanks Ice-T, I've been down the road with the parking brake, I installed airline switches to enable the DVR when they set the Maxi's. However... we ran into a few issues in the past when the officer would have the driver re-position the truck and continue attempting to update dispatch (then I get calls). We have discussed reusing this and modifying operations and more training. A few rural volunteer departments that I've set up use the parking break method with their pyramid units.

    As far as the set-up goes, I've tweaked them a few times. Simplex operation DVR is pita, multiple DVR units (+5) enabled on scene can cause intermittent audio holes, moving to duplex should resolve this. One of the big issues we get is when the guys turn them on as they leave the station and the DVR that becomes master isn't quite on scene yet or in the best location, some stations aren't too far apart. Training is helping.

    I've had a few conversations with Futurecom to iron out some of the settings.