Pro -106 and Roanoke P25

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Jvell1

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I have a pro 106 and having problems with choppy reception of the Roanoke P25 system. Anyone have any experience with this system or reasons why I am having this problem?
 

John

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The system is a simulcast system; transmitting at the same time from 4 sites on the same frequency. So scanners both from Uniden and GRE/Radio Shack can have trouble receiving the system if you are in a position where you are picking up signals from more than one site. Where are you located? A directional antenna pointed at your closest site may help. If you want to check your radio to make sure there is nothing wrong with it, I have found that downtown Roanoke is one the best places since it gets a very strong signal from Mill Mountain which tends to overpower all the other sites.
 

gcgrotz

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John, just a thought here, I had the opposite problem here in downtown C'ville, the signal from Carter's Mtn was so strong it was bouncing off buildings and causing lots of multi-path distortion. Reception was better out in the county. We had the same problem with analog TV and I installed a yagi just above the roof pointed at the mountain which cleaned it right up. Then they went digital...

The moral is do what you gotta do!
 

kc4jgc

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I'm going to be in Roanoke in a few hours (about 10am, maybe before). doing a delivery. I'll have my '106 with me. Thanks for the heads up on that potential problem. My "knee jerk" guess would be needing to activate multi-site mode to either "roam" or "stationary". I'll be on Ferncliff Rd a few hours before heading out to Bedford. I'll try to remember to have my scanner with me during the unload. It's Wednesday, time for the weekly NWR alert test!
 

John

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Ferncliff is not exactly downtown Roanoke. In fact the whole area around the airport is generally a problem because it picks up 3 sites very well (Poor Mtn, Mill Mtn and Ft Lewis). The city to resort to yagis and/or magnetic antennas in doors to get some things to work at the airport itself dor this very reason.

John
 

John

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BTW, my understanding of the multi-site or roaming function of the GRE is for wide area systems like STARS. When one particular site starts to drop below a signals threshold it will search for other sites (control channels) programmed in the scanner for the same system to attempt to find a better signal. Once it finds a signal above a set threshold it will lock onto that one until it starts to drop in quality. This is fine for a system like STARS where there are multiple sites each transmitting on different frequencies to provide wide area coverage.

The Roanoke system is not this way. It has 4 sites all transmitting on the same frequencies at the same time. Called Simulcast. They are designed to be synchronized so that effectively they sound like one transmitter to a mobile unit. There are always slight differences between the signals. Unfortunately the commercial grade equipment seems to handle this much better than scanners. Because they are all on the same control channel frequency there is nothing for the scanner to search for to try and find a better site.

A directional antenna is probably the best solution but on a mobile/portable installation that isn't feasible. My only suggestion is to keep trying different antenna systems until you find the one that works best but realize that where you are will make a sigificant difference in how well you pick it up because it will determine which sites you pick up and their relative signal quality.

Some people I know that stay in a smaller geographical area have reported some success with replacing the stock rubber duck with ones tuned for 800MHz or UHF.

John
 

John

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John,
You heard if Salem is planning on going digital in the future?
From comments I have heard they only plan to narrowband their existing conventional UHF frequencies. I wouldn't put it past them to decide to do something like MotoTurbo or some other non-public safety digital in the future but I don't think it will be anytime soon. If they do it will a real shame since they will be investing in something that is counter to the federal and industry standards and is further away from the interoperability they should be pursuing.
 

Jvell1

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That sounds like the "always independent" Salem I was born and raised in...lol
 

kc4jgc

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Wirelessly posted (SAMSUNG-SGH-T459/T459UVIA1 NetFront/3.4 Profile/MIDP-2.0 Configuration/CLDC-1.1)

For the few hours I was in town yesterday, I did notice the "choppiness" you spoke of when coming in on Orange Ave, 581 & Hershberger Rd. I tried activating the global attenuator. It helped some, but not enough. I wanted to try the multi-site function for kicks (noting what John said previously) but wasn't able to find it on the menu. Apparently I left my manual at home....


When I was in the trailer unloading, I did notice all transmissions were clear. Being surrounded by heavy aluminum definitely helped, fwiw.
 

John

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Wirelessly posted (SAMSUNG-SGH-T459/T459UVIA1 NetFront/3.4 Profile/MIDP-2.0 Configuration/CLDC-1.1)

When I was in the trailer unloading, I did notice all transmissions were clear. Being surrounded by heavy aluminum definitely helped, fwiw.
Perhaps you have hit upon a solution. All we need to do is mount our mobile scanners inside aluminum trailers and tow them behind our vehicles. :)
 

Jvell1

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From comments I have heard they only plan to narrowband their existing conventional UHF frequencies. I wouldn't put it past them to decide to do something like MotoTurbo or some other non-public safety digital in the future but I don't think it will be anytime soon. If they do it will a real shame since they will be investing in something that is counter to the federal and industry standards and is further away from the interoperability they should be pursuing.
Is it logistically possible for Salem to join the city/county P25 system?
 

John

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Is it logistically possible for Salem to join the city/county P25 system?
Sure. The system has plenty of capacity and if it can cover Roanoke Co it should have no problem covering Salem since it is wholly contained within the county. All it would take is Salem to buy the necessary radio equipment (portables and mobiles) and some upgrades to their dispatch consoles. And of course, they would have to pay their share of the system operational costs. Not cheap all the way around. Consider that a simple conventional portable can be around $300-600 while a digital trunking portable cost upwards of $1500 the costs can seem prohibitive.
 
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