Communication Project

[JAF27]

Hello,

 

I am currently working on creating a source of communication for me and my friend, and I wanted to know what the community's advice would be. I am located in Lower Manhattan, New York City and am trying to reach someone about 6-7 miles uptown. You see, my current plan is to purchase an amplifier, that along with my Baofeng UV-5R, will transmit 50 watts. Does anyone think I will be able to reach my friend with this amount of power? All of the buildings make it very difficult to get a signal through. The most power I have tried is 8 watts so far, and not a chance of signal there. I can barely reach a repeater with it!

 

Thanks!

[AdmiralCochrane]

There is a good chance that GMRS may not work for this application, regradless of how much power unless both are on the highest rooftops without taller buildings in between. 

Rooftop to rooftop would work like a dream, ground to ground with tall buildings between reduces the chances of success.

[wayoverthere]

Uhf is pretty line of sight, what is your antenna situation? That will have more effect (especially for receiving) than more power.

 

The other issue in a big city environment is noise, and the tendency for the receiver to desense to avoid overload, it may not entirely be a problem of signal reaching, but also picking it out of the noise.

 

If there is a repeater in range of both of you, maybe focus toward optimizing for that?

 

Granted vhf and uhf behave a bit differently, but 5 watts on vhf can reach the space station when conditions are right

https://www.qsl.net/ah6rh/am-radio/spacecomm/getting-started-iss.html

[berkinet]

In GMRS, and other UHF services, power is far less important than signal path. For UFH signal path is essentially LOS (line of sight). Depending on the exact frequency there may be a bit of bending, reflection or fresnel effect. But, the one sure element is LOS.  With that in mind, 6 or 7 miles at 5 watts with LOS between the two locations is no problem. Increasing the wattage to the legal maximum of 50 watts will only make a difference in terms of overcoming other traffic on the same channel. That is because of the FM capture effect in which the "louder" of two signals is heard while the weaker one is lost.  This would help you, and wipe out the other user(s) you were stomping on.  So, not a good idea.

 

Also, if you really want power then you would be advised to purchase a good quality mobile radio (possibly used) that operates at the power level you want., Not only would you get 40 or 50 watts of power (there is almost difference between the two: < 1db), but, you would also get a much better receiver that would be capable of rejecting noise and adjacent channel interference in an RF rich environment like NYC.

 

On the other hand, coupling a cheap radio like the UV-5R, with its poor quality receiver, to a cheap 50 watt amplifier, with lots of noise and spurious emissions is not only unlikely to meet your needs, but will probably piss off a lot of other nearby GMRS operators.  Also note, you can only operate simplex at 50 watts on 8 of the GMRS channels, and those are also repeater outputs and likely to be busy.  The other 14 channels limit you to 5 or 0.5 watts.

 

So, if you really want GMRS, I would suggest you look at your antenna options. A pair of good medium to high gain antennas will help focus your output power and reduce unwanted signal reception. However, beware that the limits for most of the GMRS channels (1-14) are ERP (effective radiated power) that includes any antenna gain.

 

As another option for unlicensed radio use (as opposed to ham radio) you might look at MURS. This is a VHF service and might give you better propagation in your area. There is a separate forum for MURS on the MyGMRS Forum.  Or, skip radio altogether and try an IP based approach, like Zello.

[mbrun]

Hello,

 

I am currently working on creating a source of communication for me and my friend, and I wanted to know what the community's advice would be. I am located in Lower Manhattan, New York City and am trying to reach someone about 6-7 miles uptown. You see, my current plan is to purchase an amplifier, that along with my Baofeng UV-5R, will transmit 50 watts. Does anyone think I will be able to reach my friend with this amount of power? All of the buildings make it very difficult to get a signal through. The most power I have tried is 8 watts so far, and not a chance of signal there. I can barely reach a repeater with it!

 

Thanks!

I am with others here on a number of fronts.

 

UV-5R is not a good radio choose for use in a busy RF environment. You will invariably want a radio with a much better receiver, perhaps even a high-end commercial one. While you own your UV-5R, learn what it can and cannot do so when you finally upgrade to a top end radio you can appreciate it.

 

The UV-5R is not legal for use on GMRS. If it were legal, and you used it with an external amplifier, you would only be allowed to transmit on the 8 main GMRS frequencies as berkinet has already indicated. 14 frequencies would be off limits due to the .5w and 5w limits.

 

GMRS frequencies will travel great distances when you have line of sight. Every obstacle between you and your intended receiver will reduce effective distance. In the city where you have miles and miles of tall buildings you have massive volumes of obstacles. Repeater antennas generally find their home on some of the tallest grounds available (buildings, towers, etc...) so they achieve the greatest coverage (footprint) possible. Finding a repeater in the area that has acceptable coverage in your area and you friends would be a huge win for you.

 

Without an antenna on top of your property and on top of your friends property, and without limited obstacles between these two antenna, no I do not believe that extra power will give you the results you seek. If you can, but just barely, get into a repeater with 8 watts, perhaps an increase from 8 to 50 would in-fact improve your signal strength into the repeater, but I would not expect it lead to simplex capability with your friend at that range. If I new I needed 50 watts, I would use an all-in-one radio with 50 watts, not a HT with external amp.

 

If you can get into repeater with 8 watts, but just barely, you could also consider a Yagi antenna that is pointed permanently and optimally to reach the repeater, the Yagi may make it possible to get in without an external amp. Case and point. There is a local operator that lives about 45 miles from a repeater we both use. He can get into the repeater strong enough to carry on a conversation with his HT set only to 1/2 watt. Signal is a noisy but I can still understand every word. When he kicks his power up to 25 watts, he sounds as good as operators 5-10 miles from the repeater.

 

Hope this helps.

 

MIchael

WRHS965

KE8PLM

 

 

Sent from my iPad using Tapatalk

[JAF27]

Thanks for the help everyone. I do not really have line of sight. If you had a radio service recommendation (I don't have a HAM license), that would be helpful. Because many mentioned VHF, I was thinking maybe Marine radio with 25 watts? But if you had any good ideas without using a repeater that would be helpful!

[berkinet]

Marine radio is not legal for land use, only land to sea and sea to sea.

[JAF27]

There is a good chance that GMRS may not work for this application, regradless of how much power unless both are on the highest rooftops without taller buildings in between. 

 

Rooftop to rooftop would work like a dream, ground to ground with tall buildings between reduces the chances of success.

I have a decently tall rooftop, although my buddies is somewhat shorter.

[JAF27]

Marine radio is not legal for land use, only land to sea and sea to sea.

Alright. I talked from land to sea the other day and reached a guy all the way near Atlantic City, but thanks for the suggestion.

[JAF27]

Marine radio is not legal for land use, only land to sea and sea to sea.

Do you have any idea how I could reach them through radio? Or is this just me having too high of expectations?

[berkinet]

Do you have any idea how I could reach them through radio? Or is this just me having too high of expectations?

I had suggested MURS VHF.  You can certainly try GMRS with two hand heads if you already have them. Who knows, it might just work. But, while the distance is not really a factor, other channel usage from FRS and other GMRS users will likely be the most serious problem. 

[JAF27]

I had suggested MURS VHF.  You can certainly try GMRS with two hand heads if you already have them. Who knows, it might just work. But, while the distance is not really a factor, other channel usage from FRS and other GMRS users will likely be the most serious problem. 

Yeah, I don't mind interference too much! Thanks for the help and have a great day!

[haneysa]

Do not use a CCR no matter what band you end up using. As others have said, the front-end of those  CCRs are crap! It will be very difficult to receive the signal that you want using low$ radios in that environment.  Whether you use MURS, GMRS, or amateur radio, you and your buddy need to use YAGI antennas, pointed at each other. When you decide on a band, try using PL Tones that are somewhat obscure (especially if you go with GMRS).

[gman1971]

Front end? what front end?

 

Lets not forget those things put out all kinds spurious RF noise all over the spectrum too... so you are screwing everyone over as well.. .but who cares... when the CCR range is only 1/4 mile all you need is that cheap 50W CCR PA, and crank that sucker all the way up like a boss,... lets boost those spurious dB even further, all that just to extend the range to a whopping 2 miles simplex... 

 

So, you don't mind the interference?, but what about others? so, what happens when your CCR spews all kinds of RF noise all over the band? That doesn't matter? There are some of us who care and spend a lot of money trying to avoid interference to others... 

 

G.