Missouri State Patrol plans VHF-Low band expansion

[Thunderbolt]

The MSHP has filed a formal request to the FCC to add additonal VHF-low band frequencies to their current system. Moreover, they have requested that many of their transmitters have their power levels upgraded to 15,000 watts ERP.


Here are the new freqs:

Troop A: 42.940, 42.860, and 42.920

Troop B: 42.820

Troop C: 42.100, 42.140

Troop D: 42.100, 42.580

Troop E: 42.920, 42.940

Troop H: 42.400, 42.580


In addition, the MSHP have applied to change their VHF-High band frequencies over to the new narrow band frequency spacing, which is .75 KHz., rather than .150 KHz.


73's

Ron

 

[nd5y]

Did they ever start using the rest of the new lowband channels?
I haven't seen anything posted in several months.

Tom

 

[Thunderbolt]

The MSHP, FCC licenses were officially amended to include the new frequencies, but I have not heard anything further about the project. Can anyone else elaborate more on this issue?

73's

Ron

 

[iceman47]

15,000 watts? (15KW)
Wow!
Thats more than most A.M. radio stationd transmit.
Perhaps you mis-read something?

 

[INDY72]

No its correct.. FCC allows up to I believe 2000 Watts under certian circumstances... MO SP will now be able to definitely reach thier mobiles with no problems

Heck with that power... I should be able to monitor the dispatches from my home in MS....

 

[nd5y]

15,000 watts? (15KW)
Wow!
Thats more than most A.M. radio stationd transmit.
Perhaps you mis-read something?

No, that is real. check out 47CFR90.20
http://a257.g.akamaitech.net/7/257/...access.gpo.gov/cfr_2003/octqtr/47cfr90.20.htm
look at the limitations column of the 42 MHz frequencies, they all have 3 which is:

(3) Base stations operating on this frequency and rendering service
to state police mobile units may be authorized to use a maximum output
power in excess of the maximum indicated in Sec. 90.205 but not in
excess of 7500 watts: Provided, That such operation is secondary to
other stations.

So if they are running 6 dB gain antennas and have 3 dB of transmission line & cavity loss, then 7500 W + 3 dB gain = 15000 W ERP

It makes it a lot easier to hear them in Texas.

Tom

 

[iceman47]

15KW would wipe out any other user on low band for a thousand miles or more.
California would really like this since CHP is all low band and with the same frequencies.
Be serious!

 

[iceman47]

By the way, 3DB of gain only causes a gain of 1/2 power in ERP.

 

[N_Jay]

By the way, 3DB of gain only causes a gain of 1/2 power in ERP.

Is that the "New Math"?

3dB is double the power, ERP or otherwise.

 

[nd5y]

By the way, 3DB of gain only causes a gain of 1/2 power in ERP.

Where did you get that idea?

3 dB gain is double the power. 3 dB loss is 1/2 the power



Tom

 

[iceman47]

35 years ago in school.

 

[OpSec]

15,000 watts? (15KW)
Wow!
Thats more than most A.M. radio stationd transmit.
Perhaps you mis-read something?

Not 15kw transmit power...15kw ERP. With a phased dipole array, you could get that easily. Quite a bit of transmitter is required, but it's doable.

 

[kb0nhx]

15,000 Watts

Just because we are licensed for 15,000 ERP doesn't mean we use it. We use 4-pole folded dipoles with 6 dbd gain; the "highest power" transmitters are generally set at 1000 to 1500 watts, which equates to 4000 to 6000 ERP. Most transmitters are either 300w (1200w ERP) or 100w (400w ERP)

 

[nd5y]

Re: 15,000 Watts

Just because we are licensed for 15,000 ERP doesn't mean we use it. We use 4-pole folded dipoles with 6 dbd gain; the "highest power" transmitters are generally set at 1000 to 1500 watts, which equates to 4000 to 6000 ERP. Most transmitters are either 300w (1200w ERP) or 100w (400w ERP)

Cool. I suppose "we" means you work there. Can you answer my original question?
Are you guys using all of the new frequencies yet?

Tom ND5Y

 

[kb0nhx]

New frequencies

Currently,
The only troop using the new frequencies is Troop I in Rolla. Their base station frequency is still the same, 42.580, and the PL of 186.2 is still the same, but the car to base frequency has changed.

Troop B in Macon had made their switch over, changing the base station to 42.820, but due to one of the remote transmitter antennas not working properly on that frequency, they had to switch back to 42.060 for the time being until they can get a new antenna for the remote.

Troop D in Springfield will be switching over sometime shortly after the new year. If you want a copy the new frequency plan, e-mail me direct at kb0nhx@arrl.net and I'll send the new Frequencies, Channel #'s and PL tones.

The main reason for the switch over is to alleviate interference from troop to troop.

 

[kb0nhx]

Troop G using new frequenices

Troop G has made the switchover. They are still using the same frequencies, 42.380 on base and 42.260 on cars, but the PL has changed from 186.2 Hz to 173.8 Hz.

Troop I has also made the swithover, these are the only two troops so far.

 

[crayon]

Re: New frequencies

If you want a copy the new frequency plan ..

Could you make a submission to the RRDB so that everyone can be up to date?

 

[kb0nhx]

RRDB

I will.

 

[dale5671]

How can that be possible!

I live IN Kansas City, MO and I rarely pick anything up on my 246T. Even when using the Radio Shack 800 antenna or the stock Uniden. So how are you guys hearing this from so far away when I cannot hear a thing unless they are almost on top of my place. I live in an upper level apartment with NO brick construction.

Dale

 

[jcecklund]

Dale,

Your not going to hear Highway Patrol using an 800 mhz antenna unless they are at your doorstep, 800mhz antennas are for monitoring the 800 mhz frequency range. Even your stock Uniden antenna is poor for reception.

800 mhz antennas are great for KCMO and Raytown systems.

I have purchased and installed a "Scantenna" and put it in the attic and I can hear most everything with no problem. It is a wide range base antenna that will improve reception ten fold!.

I hear the highway Patrol perfectly.

I live in Lee's Summit and can hear Troop B Macon quite well
I also have the patrols VHF UHF freqs programed and hear anything in the metro area with no problems.