Public Safety - Low Band Vs High Band

[waingro223]

Why do the state patrol use such a low band for the communications?
What are the Pros and Cons using the low band?

From what I have gathered from some police officers and research, the MSHP use a low band because the lower frequencies will travel much further than the higher frequencies and the use of higher wattage around 100 watts or more are so they can travel great distances because of the ground they have to cover and less repeater towers and the towers also are much further apart. I also heard the funding for the state patrol is much less than county and local police and that's another possible reason they have been on that low band for such a long time. Does this information sound correct?

What do you all think is the best band to use in public safety if setup properly?

 

[nd5y]

The best band to use varies with geography, desired coverage area and availability of unused frequencies.
This letter attached to a FCC application explains the reasons for MOSHP remaining on low band.
ULS Application - Public Safety Pool, Conventional - 0001110641 - MISSOURI, STATE OF - Administration
Scroll down to "Attachments" and click on "3 page letter"

 

[SCPD]

I just tried to open the info and it wouldn't open.

 

[nd5y]

Try again later. Sometimes that site is slow or doesn't respond.
Also the first page of the .pdf file is blank. It might appear that nothing loaded depending on your browser & .pdf file viewer.

 

[iamhere300]

Why do the state patrol use such a low band for the communications?
What are the Pros and Cons using the low band?

From what I have gathered from some police officers and research, the MSHP use a low band because the lower frequencies will travel much further than the higher frequencies and the use of higher wattage around 100 watts or more are so they can travel great distances because of the ground they have to cover and less repeater towers and the towers also are much further apart. I also heard the funding for the state patrol is much less than county and local police and that's another possible reason they have been on that low band for such a long time. Does this information sound correct?

What do you all think is the best band to use in public safety if setup properly?

Many reasons to use Low band, and many reasons NOT to use Low band.

When the Highway Patrol started using Low band there simply was not a lot of options available. Low band was IT. Since then, it has worked well, within the issues. Very nice when you may have no more than 5-10 cars out there in a troop.

Pros
Great mobile coverage.
Equipment was simple and reliable.
Few tower sites needed to at least talk to the cars.

Cons
Great coverage. Very often groundwave covered such a large area that frequency re-use was not available.
Skip. Lots of skip.
Equipment - very little available now a days.
If a troop G car is talking to troop, it ties up that troop frequency.
No portable coverage. Have to use expensive and not as reliable vehicle repeaters.
Poor car to car coverage.
Still lots of dead spots.

Now - to answer your question, what band is the best for public safety?

That is easy.

Low band is best.
VHF High band is best.
UHF is best.
800/700 is best.

It all depends on the situation, loading, terrain, use, etc. A properly designed system on any of the bands can be the best, depending on many different factors. No one band is "Best" for agencies in Missouri.

 

[W2NJS]

Even before what we call "low band" today (30 to 50 mHz) came into use, police used one-way transmissions at the high end of the AM broadcast band to notify units of events, around 1700 kHz. As a kid living in DC around 1946 I recall hearing the Akron OH PD on our home AM receiver. As late as the 1950s the Nassau County Police on Long Island dispatched on 2.5 mHz and the cars transmitted somewhere around 35 mHz. The 2.5 mHz was AM and the cars were wideband FM.

 

[zzdiesel]

I knew they were high power but not that much.

 

[902]

Why do the state patrol use such a low band for the communications?
What are the Pros and Cons using the low band?

From what I have gathered from some police officers and research, the MSHP use a low band because the lower frequencies will travel much further than the higher frequencies and the use of higher wattage around 100 watts or more are so they can travel great distances because of the ground they have to cover and less repeater towers and the towers also are much further apart. I also heard the funding for the state patrol is much less than county and local police and that's another possible reason they have been on that low band for such a long time. Does this information sound correct?

What do you all think is the best band to use in public safety if setup properly?

Yes, that is correct, and the other answers are correct as well. There is one more answer - MSHP's legacy operations have been on low band since radios went into the troop cars. It was possible to make incremental improvements (additional receivers, higher power transmitters, etc.) without wholesale replacement of the entire system. In the FCC's licensing scheme, the numbers begin with 200. KAA203 and the other MSHP legacy licenses of the same series were one of the first systems licensed by the FCC in the 40s.

Another disadvantage of low band is "unintentional radiator" noise from microprocessor devices. There is a legendary problem that the communications division people found in Jefferson City regarding a "dead spot" in their coverage. As it turns out, a Jeff City Mexican restaurant was a dead zone. It wasn't far from their transmitter site, but regardless, poor receive. The machine that made the tortilla chips was emitting RF around 42 MHz. Likewise there is a threat from broadband over powerline (BPL) if it is ever implemented.

 

[radioman2001]

Don't forget about GM cars PCM, they transmit a wide band signal from 42-47 mhz, probably from the processor. Caused a lot of problems for Westchester County Fire for years, big spur on 46.14 which was their coordination channel. So much so that just driving down the road you could tell if you were near a GM car. Now if you just get the FCC to do their job in regulating these kind of issues, low band could still be a viable band for use. In our case the FCC really wasn't interested in doing anything, they said go to GM.
Personally I like Low Band, no monthly fees, you don't need a big tower and with 100 watts you can cover 50 mi. NYSP still uses it for Troop to Troop coms.

 

[millrad]

The FCC license shows the low band base stations are transmitting 5K of power, with an ERP of 15K!
Is this accurate?
Seems like a very high output, but it might be needed for the vat area the base stations have to cover.

 

[nd5y]

The FCC license shows the low band base stations are transmitting 5K of power, with an ERP of 15K!
Is this accurate?
Seems like a very high output, but it might be needed for the vat area the base stations have to cover.

You didn't read the link I posted.
The application attachment explains what power levels they normally use.

 

[902]

One of the interesting things about low band is that some of these frequencies have a limitation requiring their coordination with a "State and Provincial Police" committee for avoiding interference (for "Limitation 2" only). This coordinates the use of certain frequencies in certain states for base, mobile, or both. As more agencies vacate low band, some of these frequencies free-up. With some exceptions, there is usually 1,000 miles or more separation between states assigned to be able to license a given frequency.

 

[kb0nhx]

Low-Band vs VHF Hi-band

I'm going to chime in to respond to iamhere's comments, which have several inaccuracies

There is plenty of equipment made for low-band. Kenwood, Midland, Motorola and Vertex all make low-band mobiles.

As for base stations, the MSHP is using Daniel's Electronics exciters / receivers for all base stations. They work very well, and EVERY low-band remote base and repeater has been replaced in the last 3 years. In fact, the high powered transmitters, which are called Pecos, (made by Professional Electronics Company in the 90's) were originally driven by GE Master II's, with GE Master II receiver shelves. Those were also all replaced 4 years ago. In addition, the MSHP techs completely re-built all 18 Pecos in the state (9 were built in the early 90's, the other 9 are the backups, built in the early 70s). All high-voltage wiring was replaced, all connections re-done, and every transmitter gone through with a fine tooth comb. These transmitters are simple, and can be replaced with standard, off the shelf parts from RF Parts, Mouser Electronics, Digikey, and even Radio Shack. In fact, you can find the EXACT design of the amplifiers in the ARRL handbook. I forget which year, will have to try to dig that up. And yes, they really do make the 3,000-Watts they claim, even though most run between 1500 to 2300 Watts on a daily basis.

The current system is simple. It is reliable. Unlike the new VHF MoSWIN radio system, it doesn't rely on a master switch for the troops to talk to the tower sites and the consoles have not failed in the 15 years they have been in service.

The only problem with low-band is interference from outside sources, as some have stated. From in-car noise created by cheap computer components to electrical line noise from poor power company power lines, those are the two problems fought most often.

The Pyramid SVR-200 repeaters are not expensive compared to the Motorola 700 MHz DVR (digital vehicle repeaters) that will be installed in every patrol car. Pyramids cost roughly $1200 each while the DVR's $5,000. Same for mobiles - a Kenwood TK-690H runs about $1800 with the APX7500's about $7,000. The cost "con" is inaccurate.

Another pro no one has mentioned - low-band is exempt from the whole narrowbanding fiasco that everyone else is having to deal with.

The problem with low-band will be when the 3 biggest users abandon it - which I know California is #1, and I think Tennessee and Missouri are up near the top as well. If California were to abandon low-band, the manufacturing of low-band equipment would probably drop off dramatically. However, unlike Missouri, their consultants advised them it would be better for them to keep low-band and spend their money upgrading their current system. What has been discovered over the process the last three years is that most of the Missouri low-band antennas have been in service since the mid 60's to mid 70's, well past their expected life span. When replaced with new Comprod 532-70 style antennas, and replacing RG-8 feedline with 7/8" heliax, it is amazing how quickly dead spots have disappeared! Unfortunately, southern MIssouri antenna and feedline upgrades were never really completed due to timing with the new system. For those of you in Northern Missouri that listen to the scanner, you have heard the difference.

The Motorola / P25 Kool Aid is not served at my house . . .

 

[iamhere300]

I'm going to chime in to respond to iamhere's comments, which have several inaccuracies

There is plenty of equipment made for low-band. Kenwood, Midland, Motorola and Vertex all make low-band mobiles.

As for base stations, the MSHP is using Daniel's Electronics exciters / receivers for all base stations. They work very well, and EVERY low-band remote base and repeater has been replaced in the last 3 years. In fact, the high powered transmitters, which are called Pecos, (made by Professional Electronics Company in the 90's) were originally driven by GE Master II's, with GE Master II receiver shelves. Those were also all replaced 4 years ago. In addition, the MSHP techs completely re-built all 18 Pecos in the state (9 were built in the early 90's, the other 9 are the backups, built in the early 70s). All high-voltage wiring was replaced, all connections re-done, and every transmitter gone through with a fine tooth comb. These transmitters are simple, and can be replaced with standard, off the shelf parts from RF Parts, Mouser Electronics, Digikey, and even Radio Shack. In fact, you can find the EXACT design of the amplifiers in the ARRL handbook. I forget which year, will have to try to dig that up. And yes, they really do make the 3,000-Watts they claim, even though most run between 1500 to 2300 Watts on a daily basis.
.

Come on. Lets look at reality. The amount of low band equipment compared to 20 years ago is dismal. One manufacturer making base stations out of all the ones that used to? How many 100 watt mobiles now a days?

And AS YOU SAY, with TN and MO rapidly going to other bands, it is going to leave a pile of fire departments in the northeast (a rapidly dimishing pile) and California left to entice manufacturers to carry on both their present lines, and any additions to the lines.

It simply does not leave a lot of equipment options, and shows in the future it is going to get worse.

The current system is simple. It is reliable. Unlike the new VHF MoSWIN radio system, it doesn't rely on a master switch for the troops to talk to the tower sites and the consoles have not failed in the 15 years they have been in service.

The only problem with low-band is interference from outside sources, as some have stated. From in-car noise created by cheap computer components to electrical line noise from poor power company power lines, those are the two problems fought most often.

Sure it is simple. And don't think that it does not have single points of failure either. Tower fell in Willow Springs? The ONLY communications for nearly a day was a cross band repeater thrown up on a local tower back to the troop, to give them All SO's capability by a local two way shop doing it as a favor. Then they had limited comms with a portable tower, mainly on the UHF links. (That will need to be narrowbanded)

And you state the ONLY problem with Low band is outside interference? HUH? You have the gall to say my statements have "several inaccuracies" and you post THIS?

Skip. Limited portable coverage. Limited car to car coverage. Interoperability - needing the VHF or 800 MHZ radios you complain about the cost of anyways. One car only being able to talk on a tower at a time. These are not problems?

I love Low band. It certainly has its place. Heck, I remember having to pull out the antenna on my low band portable. But as I stated, the other bands also have their place.

I

The Motorola / P25 Kool Aid is not served at my house . . .

No - maybe not - but it is certainly there in another flavor.

 

[902]

It's this vacating of low band that makes it so appealing, actually. It has become the virtual green-field that may be used to rebuild efficient systems (haphazard deployment and inefficient consumption of resources are the largest failures of high band). That, and the fact that a reasonable coverage area can be designed without the need to depend on infrastructure.

Yes, you may need transport and additional sites, but the fact that you do not need a $2M (and $35,000/mo in maintenance and upgrades) proprietary "interoperability switch" lends to rapid restoration in areas where a disaster may cause catastrophic impairment. With an infrastructure-independent system, recovery is relatively easy.

 

[iamhere300]

It's this vacating of low band that makes it so appealing, actually. It has become the virtual green-field that may be used to rebuild efficient systems (haphazard deployment and inefficient consumption of resources are the largest failures of high band). That, and the fact that a reasonable coverage area can be designed without the need to depend on infrastructure.

Yes, you may need transport and additional sites, but the fact that you do not need a $2M (and $35,000/mo in maintenance and upgrades) proprietary "interoperability switch" lends to rapid restoration in areas where a disaster may cause catastrophic impairment. With an infrastructure-independent system, recovery is relatively easy.

And it is appealing - to us. To the manufacturers however, unless something "new and exciting" it will most likely lay fallow.

 

[mancow]

The MO system is absolutely amazing. Where I get dead spots within Kansas listening to local agencies on Vhf and 800 I can STILL clearly hear Troop A Rural from Missouri clearly on my X9000.

 

[iamhere300]

The MO system is absolutely amazing. Where I get dead spots within Kansas listening to local agencies on Vhf and 800 I can STILL clearly hear Troop A Rural from Missouri clearly on my X9000.

Agreed - I can pick up G in Chattanooga on my mobile.

Funny thing was, I saw no MO HIPO cars near me though.

 

[902]

And it is appealing - to us. To the manufacturers however, unless something "new and exciting" it will most likely lay fallow.

It's called marketing. Look at how hot these $7,000 radios with displays are selling because it's all hyped up. I was on the phone with one guy who had one this morning. I asked him if he could access Youtube on it in between calls. He said all he can get in there is a channel display. My reply was, "Don't you feel stupid for spending that much on something you can't even watch?" His response was, "We'll be able to get Hulu when we get some D Block stuff."

I just don't know...