5 watt handheld radio transmit distance

[nd5y]

There is free software available that predicts radio coverage using terrain elevation data and transmitting and receiving station specifications. Radio Mobile WEB Site

[gh2]

I cannot hear the repeaters 30 miles away on a scanner.
In another direction I can hear repeaters 30 miles away.
Will the receive range be about the same as a scanner?

Thank you.

[nd5y]

If you can hear a repeater on a hand held scanner you should probably be able to work it with a hand held radio assuming that it is a well engineered system and the receiver and transmitter are in the same location. But maybe not. It depends on a lot of factors.

[prcguy]

nd5y has it right, HT is short for the early Motorola Handi Talkies, some had model #s that started with HT like the HT200 and HT220. Oh how I wanted one of those in the 1960s but they might as well have been made of unobtainium back then.
prcguy

Originally Posted by Ed_Seedhouse

Around my parts everyone seems to think it stands for "Handheld Transceiver", which is nicely descriptive, but your idea sound reasonable too.

[k3cfc]

Originally Posted by gh2

What would be the most range with a after market longer antenna.

Thanks.

It's like this. you get new brakes on your car. and you ask how long till i need new ones again. well if you only drive on sunadys ( to church ) then you probably will need a new car before new brakes. in the world of radio you just do what you can with what you have NO GUARANTEES.

[Ed_Seedhouse]

Originally Posted by nd5y

When I lived in El Paso I could work a repeater about 120 miles away on a mountain top near Silver City NM with a 5 W hand held standing in the front yard. When I lived in the DFW area there were repeaters 10 miles away that I could not work with a hand held but during good tropo openings I have worked repeaters in Houston and Oklahoma City from the DFW area.

The point the OP seems to be missing is that at two meters and above everything is pretty well line of site. So in general if you can see it you can work it and if you can/'t see it you can't work it. So the rule of thumb response, to "can I work something?" is, "can you see that something?".

If you could see it if a large building or land formation replaced by a mirror then you have a decent chance of working it, but there is no guarantee.

Truly reliable communication at these frequencies is line of site. Yes, there are phenomena such as atmospheric ducting that can cause exceptions but that's what they are - exceptions. Of course, many hams make a business of finding and using these exceptions and more power to them.

But the general rule applies in most cases.

[ab3a]

If you're transmitting from hand-held radio to hand-held radio, in a forest valley, then two to five miles would be pretty much what I would expect.

However, if you ask what is possible... Well, I can recall standing on the beach in Tel Aviv decades ago with a friend who communicated to Malta over 1000 miles away with just 300 mW and a 5/8 whip. The other guy had a rubber duck antenna and 2 Watts. I can also recall using the repeaters in Cyprus from Haifa, nearly 200 miles away --every afternoon for week after week with a handheld radio on 145 MHz.

There are people who manage to communicate from California to Hawaii in much the same manner.

The secret is that these paths were over water and that with the right weather conditions you can form very effective radio wave ducts that can carry signals for a long way over the horizon.

You can also go from mountain top to mountain top. Some guys sell portable VHF and UHF yagi kits. You may want to look at using something like that if you need to communicate across longer distances.

[zz0468]

Originally Posted by gh2

I cannot hear the repeaters 30 miles away on a scanner.
In another direction I can hear repeaters 30 miles away.
Will the receive range be about the same as a scanner?

Thank you.

You're asking for specific answers, but specific answers are virtually impossible with the information given. Range is determined by:

Transmitter power
minus transmitter feedline loss
plus antenna gain
minus free space loss (determined by frequency and distance)
minus additional path losses
plus receive antenna gain
minus receiver feedline loss

The remaining signal must be greater than the receiver threshold (sensitivity).

We have transmitter power. We can calculate free space loss based on 30 miles. There are too many other missing pieces to determine the range. The fact that you can hear repeaters 30 miles in one direction, but not 30 miles in another is good evidence that other factors (those additional path losses) exist.

So, let's do this... Assume a 30 mile unobstructed path, 5 watt portables, unity gain antennas, and 0.25 uv sensitivity. I'm converting to db because it makes the math simple.

Transmitter power = 37 dbm (5 watts at 50 ohms)
minus transmitter feedline loss = 0 db (portable antenna)
plus antenna gain = 0 db (portable antenna)
effective radiated power= tx power plus antenna gain +37 dbm
minus free space loss -119.2 (30 miles, 450 mhz)
minus additional path losses 0 db (free space, line of site)
plus receive antenna gain= 0 db (portable antenna)
minus receiver feedline loss = 0 db (portable antenna)
received signal strength= -82 dbm (ERP minus pathloss plus RX antenna gain)
receiver threshold= -119 dbm (0.25 uv at 50 ohms)

This path has a 37 db margin. That's a perfect path, not taking into account any losses other than free space path loss. In reality, there WILL be additional losses, we just don't know what they are, therefore can't adequately predict performance, based on what you've given us. BTW, the fact that the path loss is equal to the receiver threshold is purely coincidental, but it makes the already simple math even simpler.

But let's stretch the distance to see where the fade margin goes to zero...

That would require that the received signal level be reduced to the receiver threshold, or -119 dbm (.25 uv at 50 ohms). That value would be
-119 dbm minus 37 db, or -156 db of total path loss required. That distance (at 450 MHz) is about 2100 miles. The only place you'll get that kind of range from a pair of 5 watt portable radios will be in space.

Because we don't know what all the other losses are... terrain, vegetation, buildings, radio performance, weather, antenna patterns, etc. etc. etc. just plan on something less than that. You see why asking a simple question like "what is the range of radios" is close to impossible to answer without detailed information?

[acyddrop]

Not that this is necessarily relevant, but I've talked to Satellites using my HT and 2 watts and those are 50 miles up. That was using an Arrow II antenna (which is a beam antenna) and it's also essentially line of site. So the question "how far can I transmit" has a lot of variables...

Just think this way, if the signal has to go through a lot of stuff (whatever that stuff happens to be) to reach your intended target the more degraded your signal will become generally speaking. This is particularly true for VHF/UHF. If the antenna of your HT is high up, and above obstructions the signal will travel further (generally speaking) than if it's lower and has to deal with a lot of obstructions. With my 5 watts HT I can hit a repeater 4 miles from my house with an aftermarket antenna on my Icom radio. However if I attach the same 5 watts through an Arrow II I can talk to West Palm Beach which is 25 miles from here, but it doesn't full quiet the repeater. The repeater antenna is up very high though which is why I can do that. It really all depends on factors that are really out of your control.

[Rt169Radio]

There are lots of things to consider when looking to see how far a HT can transmit on 5 watts. But if everything is just right you can get some distance (at least when using a repeater) In my current location I can use a repeater that is about 30 miles (as the crow flies) away using 2 watts or 5 watts.

[Ed_Seedhouse]

Originally Posted by acyddrop

Not that this is necessarily relevant, but I've talked to Satellites using my HT and 2 watts and those are 50 miles up.

I highly doubt that. Fifty miles is just too low for a satellite to stay up. Low Earth Orbit altitude is generally considered to be from 160 miles up and objects orbiting lower than 120 miles decay rapidly.

[k3cfc]

Originally Posted by acyddrop View Post
Not that this is necessarily relevant, but I've talked to Satellites using my HT and 2 watts and those are 50 miles up

Do you want to share what your smoking?? i want to talk to a sat also that's 50 miles up. lol

[Fuzy_GSXR1000]

Gh I have a Kenwood HT with a Diamond SRH320A it's good for 2m/1-1/4m/70m Rex and 120,150,300,450,800,900Mhz receiving and works great!!! With 5 watts you should do 30 miles with this setup I have hit mobiles driving home that far or further!! PM ME WITH ANY QUESTIONS!!! Nine times outa of ten if you don't have the right pl tone in if they change it you don't have the most current one in you won't hit the machine.

[acyddrop]

I meant to say "at least 50 miles up". Which is inherently wrong I admit, but that is on the ham radio test like that and I quoted it stupidly. The fact is any LEO object is between 99 miles and 1,200 miles above earth. Thanks for keeping me honest.

Originally Posted by Ed_Seedhouse

I highly doubt that. Fifty miles is just too low for a satellite to stay up. Low Earth Orbit altitude is generally considered to be from 160 miles up and objects orbiting lower than 120 miles decay rapidly.

Originally Posted by k3cfc

Do you want to share what your smoking?? i want to talk to a sat also that's 50 miles up. lol