Not really sure where this topic belongs. Admin, feel free to move this where it belongs.
Looking at getting one or a few vehicular repeater(s). Only need it for one channel so I was leaning on the SVR200.
We have a terrible time with portable radios transmitting to our dispatch on our repeater. An idea arose to look at maybe trying a vehicular repeater to make it better.
We are on vhf 137-174 band split.
Using CDM 1550 mobile radios in the trucks.
Are these VR units any good?
What is everyone's experience with them?
Kevin
Sent from my XT1097 using Tapatalk
1) I would not ignore the option of installing a voted system to improve your portable talk back. JPS now offers an option with their SNV-12 voter to better utilize internet / IP back haul. Where your agency has a WAN connection you can install a satellite receiver. No phone line leases, no microwave required. The new JPS option is better integrated in the past. Please look into the cost if doing this before committing to vehicle repeaters. A big question is the size of the fleet as well as where you need coverage and where you might place a satellite receiver. A voting system is the best solution.
2) While you can do what you want with a Pyramid SVR200, unless you have dual band portables, the vehicular repeater will be "In Band" meaning that RF notch filters will be required in each mobile to allow for the duplex operation of the repeater. It can be done, and new frequencies were allocated near the top of the VHF band to accommodate this, but it will require some attention to detail and potential compromises.
3) The Pyramid SVR200 is a fine product, Pyramid has focused on a niche that they serve well and there should be application notes on their website to work with your radios. The priority technology used in the SVR200 was developed by Motorola, is proven and worked well 40 years ago.
4) An SVR needs to be activated when on scene. This can be done in a number of ways. Some agencies use a manual switch, but if the officer bails out and forgets, the repeater will not be activated. This means he will not be able to transmit through the repeater, nor hear dispatch.
A better solution is to wire a switch that activates the repeater when the vehicle is placed in PARK. The radio will also need to be powered on when the vehicle engine is off so it is assumed that a battery protection run/shutoff timer is installed.
5) Whenever a SVR200 arrives on the scene and is activated, it transmits a specific audio tone that is recognized by all other SVR's in range. This tone tells the other SVR's who is "boss", and that most recent SVR is the only one that will repeat. The other SVR's will wait some random 10's of milliseconds and if the "Boss" does not transmit, during the first few milliseconds, one of the other repeaters will take priority and become the "Boss".
6) There is a priority interrupt timer so that a portable can transmit back to the repeater during the repeater drop out delay. This causes a clicking on the VRS signal toward the portable. It is a necessary feature. It also means that a few milliseconds of audio might be missed waiting for the priority interrupt interval. (A training issue)
7) The portable radios receiver and the VRS transmitter must operate in the carrier squelch mode for the system to work with multiple VRS on scene. So some interference might be heard on the portable.
In my opinion, it is a workable solution, but has some quirkiness that may make it annoying under stressful communications. If your department is 15 officers and 5 vehicles and the officers are "techies" who can operate a cable TV remote control without getting frustrated, it will work. They do need to fully understand the operation and limitations of the system. If they are not so forgiving of quirky tech (untrainable), then satellite voting receivers might be a better solution.
One of my first assignments as a tech rep was to explain to a rural county sheriff in Iowa how the Motorola vehicular repeaters operated. His response to me was "I don't want to know how it works, I just want it to work". His department was not a good match for that solution.