4 antennas on VSP
- Thread starter waynes
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Mr_Boh
Member
Guess a photo would help determine what you are looking at better because depending on which cruiser in terms of age and other things, it's either for cellular data or local interop (as in talking on 800MHz to the local jurisdiction without patching through STARS).
the flat one I believe is GPS and the other stubby is for the MDT data
My guess, front-to-back:
1. VHF-High band loaded 5/8 wave (STARS)
2. 7/800 1/4 wave radome (regional trunked systems)
3. GPS/cellular radome (mobile computer)
4. 700 MHz quarter wave (DVRS)
5. VHF-Low band loaded 1/4 wave (SIRS)
2 & 4 could be reversed. Again, this is just my guess.
Is it common for state cruisers to have local/regional trunking radios in their cars? I was thinking not, since they often seem to use other methods to communicate with local counties.
Ok, I went back and looked at a thread on interoperability between state and county (VSP with county radios) and saw reports that some counties provide local troopers with trunked system radios. However they are often portables.
Mr_Boh
Member
Yeah in your photo it is more than likely the LTE data antenna with a GPS puck just behind it. Likely a Laird TRA6927M3NB-001
#2 looks like the roof mount on my vehicle: Motorola 700/800 3 dBi low profile, not sure of the part number.
topcop1833
Member
#2 is LTE, everything else is correct. You won't see a permanently mounted antenna for any local systems. You might see an extra antenna on K9 cars for the door pop thingy.
Seems likely to be LTE for cellular data as you state their are no permanently mounted antennas (and I assume mobile radios) for local 700/800 systems. Attached is an image of the 700/800 antenna on my vehicle.
TJX400
Member
If VSP was smart, they would patch talk groups and frequencies of local agencies into STARS. That way there's no issue of purchasing more radios or relying on counties to provide them. Especially when there are crashes or large incidents, you have to rely on the state communications center to call the county or city communications center by phone, relay the information, and then wait for that to be relayed to defined personnel. I feel having a patch (either permanent or temporary) would fix that entire issue.
clbsquared
Member
The irony in all this is the fact that in todays world of Public Safety Communications Interoperability push, there is still no interoperability. Motorola pushed a 700/800 P25 system for us all in the name of interoperability. The only problem with that is, the agencies that we need to have interop with are on either VHF analog conventional, LTR, VHF P25, UHF P25 or 700 P25 (Harris) Phase II. The agencies that we DO have interop with are agencies that we never assist.
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It also depends on region. The NCR jurisdictions seem to have robust interop in the 700/800 band. The Maryland statewide system hosts several Federal agencies, and I expect it will support VSP in some capacity when Phase 5 becomes operational.
I can see VSP getting support from the MD1st system when P5 is activated especially in NOVA and along the Potomac River for the Chesapeake area of VA as well but it will not do anything to support the Shenandoah Valley all the way down to the TN/NC Va boarder. I wonder if its getting any help from NC VIPER along the NC/VA line?
clbsquared
Member
Not in Southeast VA.
NC VIPER has nothing to do with Virginia STARS and VSP. There was a common link between most of the Tidewater cities that included Elizabeth City in NC called TCAP on 453.8 for many years. Only the dispatch offices had it on their consoles. I used to be a radio technician for the City of Norfolk Radio shop many years ago when they were on vhf high band and was also a part time dispatcher for Norfolk Police and Fire. All the area dispatchers did a role call at 11pm.
kayn1n32008
ØÆSØ
1: Is a VHF 1/2 wave, it's too short to be a 5/8 wave. Likely they need more bandwidth than a 5/8 will provide. 5/8 waves are good for about +/-2MHz from centre frequency, 1/2wave cut for 162MHz will give an acceptable match from 150-174MHz.
2: Looks like a 7/800MHz, toss up between cellular and LMR, but likely for a LMR radio.
3: Multiband cellular/GNSS combo antenna, for MDT/MWS.
4: 1/4 wave, looks like 700MHz.
5: VHF-Lo, base loaded 1/4 wave.
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