What frequency to choose?

[ASAD]

I'm trying to get a business radio license but want to know which frequency/band would be efficient for an area like Long Island, New York. Should I be looking in 148-172, 400-420, or above 450 MHz? I want to get strong signals while working inside houses, and still get a decent range out of the system.

Your help will be highly appreciated.

 

[W2NJS]

You would have to define what range you need for anyone to give you even a guess at the answer.

400-420 is restricted to Federal licensees in the USA, as is 148 to 150.8 mHz. Above 450 is your best bet.

Perhaps a better choice would be to consult with a radio service shop as you might be able to rent time on one of their repeaters to test various units.

 

[ASAD]

You would have to define what range you need for anyone to give you even a guess at the answer.

400-420 is restricted to Federal licensees in the USA, as is 148 to 150.8 mHz. Above 450 is your best bet.

Perhaps a better choice would be to consult with a radio service shop as you might be able to rent time on one of their repeaters to test various units.

I need coverage of about 20-mile radius. I'll have a base, a mobile, and a few HT's (for HT to HT communication). How about if I use a huge base antenna such as Diamond F23H in the neighborhood of 160 MHz? Or should I still be looking above 450 to get signal inside houses?

P.S. Repeaters and dipole-array antennas are too expensive for me at this point.

 

[xts3000r]

what is the radios used for. and are you wanting handheld to base. or mobiles to base.

 

[902]

Business radio licensees are handled on a basis of loading. The frequency coordinator you select will help you choose which frequency is best when you fill out and submit your FCC Form 601 and coordination fee to them. You may select a frequency yourself, but you are best served to defer to the frequency coordinator. They see things about frequencies and other licensees that you do not.

The choice of what frequency band you want to use may also be a function of what kind of system you wish to deploy. How many units will you have? Who are you communicating with? Is this a simplex system, or a repeater? Will you be using your system 24/7 or during business hours? Is your system analog or digital, and, if it's digital, what is its occupied bandwidth?

Also, to echo W2NJS, consider that there are mobile system operators who have "community repeaters" or trunked systems that you can rent time on. This saves you the expense of buying everything, licensing it all, and putting it together. The advantage here is that many of them pay to be on very good sites that can provide you with an exceptional footprint and coverage. If you put something on your house on Long Island, I can pretty much guarantee you that you will not achieve hand-held in-building coverage within a 20 mile radius.

 

[ASAD]

I'll be doing base <-> mobile, base <-> handhelds, and handhelds to handhelds. Simplex. Analog. Transport company.
Should I be requesting between 150-174 MHz or above 450 MHz? (for my information)

 

[902]

I'll be doing base <-> mobile, base <-> handhelds, and handhelds to handhelds. Simplex. Analog. Transport company.
Should I be requesting between 150-174 MHz or above 450 MHz? (for my information)

VHF simplex should work to some extent. 450/460 is paired and your simplex operations might be overtaken by a repeater system that shares the frequency with you. The FCC offers no protection for that on "shared use" frequencies.

Have reasonable expectations. Many of the business channels are used by car services in NYC. If you're fortunate enough to find a frequency that is not monopolized by one (or more, like one in the Bronx and one in Brooklyn), your range with something on a warehouse, garage, or house, may make 20 miles from base to mobile, but will probably not do base to portable at the edge of your area of operation. Portable to portable operation simplex is catch as catch can. My experience is about 2 miles using 5 Watt VHF portables, me using a portable in the car, my son using a portable in the house. UHF is about the same. Don't believe the marketing claims on the blister-packed radios in the big box stores. The only way one of those could go 30 miles to another is with both of you standing on two mountains and no other stations interfering with you both.

Shop around and find an honest radio shop that you have good feelings with. No high pressure sales, just someone who's willing to help you out and provide the tools you need, not the tools they want to sell you. You have a lot of options, but like I said, be realistic about range.

Best of luck and hope you grow a prosperous business.

 

[n5ims]

I'll be doing base <-> mobile, base <-> handhelds, and handhelds to handhelds. Simplex. Analog. Transport company.
Should I be requesting between 150-174 MHz or above 450 MHz? (for my information)

I'm not trying to be flippant here, but what is your real goal here, have your own radio system or have a way for your transport company to communicate (yes, this is a serious question). If you simply want your own radio system then apply away, spend your money on radios, licenses, installation, etc. and have fun. If your goal is to communicate a build-it-yourself system will be expensive, troublesome, and probably not going to provide you the results you're looking for. There are several reasons for this.

First off, a VHF-Hi band frequency will be pretty difficult to find. They're basically all used up (well, taken is probably a better word since they may not actually be in use, but that won't matter for someone trying to get a new frequency on that band). The UHF band is also pretty crowded, but your chance of getting one is better. You may be lucky, but using a frequency coordinator (as suggested above) will be the only way you will find a good frequency.

Your 20 mile range Base <--> Handheld will require a nice, tall tower (or a nice, high remote base site), quality antenna, and low loss commercial coax. None of these will be cheap. The Base <--> Mobile 20 mile range will be easier to accomplish, but still will require a pretty good cash outlay to do so.

Using a radio company's existing infrastructure will buy you two things. First, it's up to them to build and maintain the system. The coverage is "guaranteed" (note the quotes here, it's because you'll never get 100% coverage) and you should be able to discover where you will and where you won't have coverage prior to spending much cash. If you build it yourself, you'll have spent your wad and may find that important areas provide only minimal coverage at best.

Also with your own system, you'll need to spend lots up front and spend some more as you go for maintenance, repair, and unless you're really lucky and have a great site available at no cost from your "Uncle Bill" the rent on your tower or roof-top space won't be cheap. Going with a radio company, you may be able to rent the radios along with the air time so your build cost may be rather small.

Doing it alone, you'll have a single site system. Where it reaches, it reaches. Where it fails, it fails. Your expansion options are very limited as well. It may not be possible to upgrade it from simplex to a repeater type system (there may not be an available frequency when you decide to upgrade) or you may be forced to change bands to do so. With a radio company's system you could be one user on a large trunking system that may have several sites available for you to use. Other sites may be linked in to allow you to expand your coverage by simply purchasing additional coverage from them, probably just needing your radios be reprogrammed, or perhaps without changing your radios at all.

 

[mmckenna]

ASAD,

Don't try to reinvent the wheel here. What you want to do isn't going to be cheap. One easier solution you should research is to check around the existing radio shops in the area. Many of the run repeater systems that you can rent space on. It will give you more reliable coverage and less initial cost. You might think it will cost more in the long run, but you really need to remember that a radio system is -ALWAYS- going to require maintenance. That maintenance is not going to be cheap. If you rent repeater space from a provider, you'll avoid all that uncertainty and get more reliable service.

Setting up your own system is certainly possible, but you've got a lot of work to do. Getting 20 mile of range isn't impossible, but it's going to require a high tower, big antenna and expensive feed line. You won't be able to just install your own tower where ever you want. There's all kinds of zoning, public comment, etc. Maintaining that tower/antenna/feed line requires specially trained people. If the tower is tall enough to require lighting or painting, thats going to cost.

Getting the licenses is going to cost you a few hundred bucks to start, and periodic renewals.

Equipment purchase, installation and maintenance is going to be costly.

Before you get to far down the road on this, check around with local providers and see what they charge. They'll likely have better coverage and a more reliable system.

 

[ASAD]

I'm trying to get a business radio license but want to know which frequency/band would be efficient for an area like Long Island, New York. Should I be looking in 148-172, 400-420, or above 450 MHz? I want to get strong signals while working inside houses, and still get a decent range out of the system.

Your help will be highly appreciated.

Thanks for all the feedback. I appreciate it. My cousin and I started a joint venture near Dubai, which is why I was comparing to Long Island. My men are usually on the road but when they unload trucks, they do go inside houses/buildings. There's a lot of activity on VHF Hi band in Dubai but I may be lucky to get a couple frequencies assigned (in case I go for a repeater in future). I have done some homework, didn't find any 3rd party radio services in the area.

Going back to my original question. Assuming I'm setting up my own radio network, can definitely obtain frequency assignment; here's my dilemma.

a...........................................................b.
...VHF...................................................|......UHF
150-174 MHz........................................| 400-420 MHz
Diamond F23H antenna --.....................| Antenex FG4065-
- tunable in 144-174 MHz range...........| - tunable in 406 - 416 MHz
Gain is 7.8 dB.......................................| Gain is 5 dB
radio power 50 watts..........................| Radio power 45

No problem with the tower for sure, which would be about 70' and coax cable will be 100' Times Microwave LMR-400. I know ERP will vary. Speaking of about 20 mile radius, base <-> mobile, base <-> portable, 6 units, would you go with option a or option b in a suburban area?

 

[popnokick]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_3 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B329 Safari/8536.25)

www.telecomny.com is one of the LMR / SMR firms in NY area.
Nassau Suffolk County Communications is another
http://longislandradio.dealerarena.com/

 

[mmckenna]

For a 70 foot tower, you would want something better than 100 feet of LMR 400.
On VHF, 100 feet of LMR400 is going to lose 1/4 of you signal just in the cable.
On UHF, you are going to lose almost half your signal.

For a reliable system, you should be using something like 1/2 inch Heliax at minimum, and you'd be better off with 7/8th's.

 

[mmckenna]

You'll want better antennas also. Your antenna system will be critical to the system coverage. Figure on spending $1000 or more for a decent antenna, and at least that amount on your feed line, connectors, lightning protectors, ground system, etc.

 

[902]

Thanks for all the feedback. I appreciate it. My cousin and I started a joint venture near Dubai, which is why I was comparing to Long Island. My men are usually on the road but when they unload trucks, they do go inside houses/buildings. There's a lot of activity on VHF Hi band in Dubai but I may be lucky to get a couple frequencies assigned (in case I go for a repeater in future). I have done some homework, didn't find any 3rd party radio services in the area.

Going back to my original question. Assuming I'm setting up my own radio network, can definitely obtain frequency assignment; here's my dilemma.

a...........................................................b.
...VHF...................................................|......UHF
150-174 MHz........................................| 400-420 MHz
Diamond F23H antenna --.....................| Antenex FG4065-
- tunable in 144-174 MHz range...........| - tunable in 406 - 416 MHz
Gain is 7.8 dB.......................................| Gain is 5 dB
radio power 50 watts..........................| Radio power 45

No problem with the tower for sure, which would be about 70' and coax cable will be 100' Times Microwave LMR-400. I know ERP will vary. Speaking of about 20 mile radius, base <-> mobile, base <-> portable, 6 units, would you go with option a or option b in a suburban area?

I've been to Dubai. It's very hot and there are more shopping malls than Paramus, NJ there. No abaya is complete without Jimmy Choos. Saw a lot of expats, and very glad I didn't have to drive. Most of what I saw was running TETRA.

Just to be certain, you are setting up in the UAE and not Massapequa, right?

Contact the Ministry of Communication and Information Technology for better instructions on licensing. Traditionally, UHF uses repeater systems, but that does not mean simplex cannot be used.

Your gain from a Diamond F23H antenna is no greater than 5 dBd. Yes, I know, 7.8 dB is in the sales literature, but this is marketing. To make this look like a super performer, they use the "isotropic" gain. That said, I have a F23H and it performs well for my use. Not stellar, but fine. Electrically it's the equivalent of a more solid antenna, but physically, not so much. Under high wind load, the antenna flexes a great deal. I don't beat up on Diamond, the RF Parts guys have been very helpful to me.

LMR400 works okay in simplex systems. 1/2" LDF hardline is a better idea and results in less loss/more power delivered to the antenna. I would be comfortable using LMR400 for 6 m or so (or to make flexible jumpers in SIMPLEX systems, if you have any notion of repeaterizing, use RG-214 instead), 1/2" for up to 30 m. and 7/8" beyond that on VHF.

 

[ASAD]

I've been to Dubai. It's very hot and there are more shopping malls than Paramus, NJ there. No abaya is complete without Jimmy Choos. Saw a lot of expats, and very glad I didn't have to drive. Most of what I saw was running TETRA.

Just to be certain, you are setting up in the UAE and not Massapequa, right?

Contact the Ministry of Communication and Information Technology for better instructions on licensing. Traditionally, UHF uses repeater systems, but that does not mean simplex cannot be used.

Your gain from a Diamond F23H antenna is no greater than 5 dBd. Yes, I know, 7.8 dB is in the sales literature, but this is marketing. To make this look like a super performer, they use the "isotropic" gain. That said, I have a F23H and it performs well for my use. Not stellar, but fine. Electrically it's the equivalent of a more solid antenna, but physically, not so much. Under high wind load, the antenna flexes a great deal. I don't beat up on Diamond, the RF Parts guys have been very helpful to me.

LMR400 works okay in simplex systems. 1/2" LDF hardline is a better idea and results in less loss/more power delivered to the antenna. I would be comfortable using LMR400 for 6 m or so (or to make flexible jumpers in SIMPLEX systems, if you have any notion of repeaterizing, use RG-214 instead), 1/2" for up to 30 m. and 7/8" beyond that on VHF.

Thanks for all the help. Appreciations. The station is going to be in suburban Dubai.

In regards to advertised antenna gain, is this the case with all brands or just Diamond? How about Antenex FG4065, claiming 5 dB? Is that right? I also have Comet CA-F22GF advertising 5.5 dBi whose length is about 5'. Could it be close to accurate?

Best Regards,
Asad

 

[902]

Thanks for all the help. Appreciations. The station is going to be in suburban Dubai.

In regards to advertised antenna gain, is this the case with all brands or just Diamond? How about Antenex FG4065, claiming 5 dB? Is that right? I also have Comet CA-F22GF advertising 5.5 dBi whose length is about 5'. Could it be close to accurate?

Best Regards,
Asad

Watch out for the dune buggies in the suburbs! I went out with a tour and rode some of the dunes not far outside the city. I am also impressed with the DCAS. The men and women who work there are very dedicated and just like the people I worked with here in the U.S. years ago.

The laws of physics help you distinguish antenna size and performance. Here, the land mobile radio industry uses decibels referenced to a dipole, while we use decibels referenced to an isotropic (theoretical) radiator for microwave. They are interchangeable, but the figures are about 2.14 dB difference. Here is the reality: a 10 dBd (~12.14 dBi) UHF antenna is about 20 feet long. That is the same size as a 5 dBd (~7.14 dBi) VHF antenna. Anything shorter, and the reference must be questioned.

The 5.5 dBi antenna is about 3.36 dBd, and that is probably a correct length, considering mounting surface and the wavelength of radiators/phasing arrangement. Regardless, your ability to communicate will depend on system gains and losses, along with terrain, clutter, and building attenuation. Using the lowest loss and highest gain materials within your budget will increase your possibility of success. 32 km in light construction might be possible, but you would need a high site. Typical portable coverage on VHF is about 16 km into a site that's about 60 m high. Less than that, and your possibilities are more limited.

I don't know what your 420 MHz landscape looks like, but with a repeater, you would be able to use preamplification devices to increase your link budget. I will say that a UHF repeater using a 7 dBd antenna up about 10 m provides me with about a 12 km range over relatively flat land. You would probably benefit from some local contacts. Know anyone in the Emirates Amateur Radio Society?

 

[ASAD]

Watch out for the dune buggies in the suburbs! I went out with a tour and rode some of the dunes not far outside the city. I am also impressed with the DCAS. The men and women who work there are very dedicated and just like the people I worked with here in the U.S. years ago.

The laws of physics help you distinguish antenna size and performance. Here, the land mobile radio industry uses decibels referenced to a dipole, while we use decibels referenced to an isotropic (theoretical) radiator for microwave. They are interchangeable, but the figures are about 2.14 dB difference. Here is the reality: a 10 dBd (~12.14 dBi) UHF antenna is about 20 feet long. That is the same size as a 5 dBd (~7.14 dBi) VHF antenna. Anything shorter, and the reference must be questioned.

The 5.5 dBi antenna is about 3.36 dBd, and that is probably a correct length, considering mounting surface and the wavelength of radiators/phasing arrangement. Regardless, your ability to communicate will depend on system gains and losses, along with terrain, clutter, and building attenuation. Using the lowest loss and highest gain materials within your budget will increase your possibility of success. 32 km in light construction might be possible, but you would need a high site. Typical portable coverage on VHF is about 16 km into a site that's about 60 m high. Less than that, and your possibilities are more limited.

I don't know what your 420 MHz landscape looks like, but with a repeater, you would be able to use preamplification devices to increase your link budget. I will say that a UHF repeater using a 7 dBd antenna up about 10 m provides me with about a 12 km range over relatively flat land. You would probably benefit from some local contacts. Know anyone in the Emirates Amateur Radio Society?

Thanks for explaining me the difference between d and i.
I'll get one of those dunes.

If you tune Diamond F23H to 170 MHz, its length will come down to 9' or so. In this case I don't think I'll need all 3 fiberglass tubes on the antenna. I'd leave the bottom two on and get rid of the top one, which would make the antenna lighter. Does it come with an extra cap to put on the (currently) middle tube in case there's no need for the top one? Or is there a way to remove the bottom fiberglass tube and collapse the antenna to two tubes?

 

[902]

Thanks for explaining me the difference between d and i.
I'll get one of those dunes.

If you tune Diamond F23H to 170 MHz, its length will come down to 9' or so. In this case I don't think I'll need all 3 fiberglass tubes on the antenna. I'd leave the bottom two on and get rid of the top one, which would make the antenna lighter. Does it come with an extra cap to put on the (currently) middle tube in case there's no need for the top one? Or is there a way to remove the bottom fiberglass tube and collapse the antenna to two tubes?

No, I don't think so. Seems like the outside metal stub is glued to the topmost tube. You might be able to cut the bottoms, but I don't know. I'm using mine at full-length. Worst case is you use the whole fiberglass tubes. I'm not sure if that metal tab is attached to the internal radiator as like a static dissipator. I didn't pay attention when I was putting it together.