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#1
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I hope that this is the right newsgroup for posting this question. I
wasn't sure where else to post it. I am looking for a single FRS type radio to communicate with a group of people who already have a radio. They are using motorola talkabout radios, and I think the model number is t5620. I know that the model number doesn't matter, just as long as the radio that I get has the subchannels that they are using. It is my understanding that these radios require a license. I found a single motorola talkabout radio at Best Buy, but it has a 5-mile range capability. I ended up buying a 2-pair pack of the talkabouts that have a 2-mile range. If I return the 2 pair pack and get a single at the 5-mile range, will I need to apply for a license even if I am going to be communicating with someone at 2 or 3 mile range? |
#2
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GMRS requires a license. You won't notice much, if any, difference
with a 5 mile radio, the built in antenna is the limiting factor. Get the two-pack, you'll have one to share. A single two-way radio is no fun . : You may need to get a radio with PL or CTCSS (same thing). These are subaudible tones that activate the squelch in their radios. Charlie wrote: I hope that this is the right newsgroup for posting this question. I wasn't sure where else to post it. I am looking for a single FRS type radio to communicate with a group of people who already have a radio. They are using motorola talkabout radios, and I think the model number is t5620. I know that the model number doesn't matter, just as long as the radio that I get has the subchannels that they are using. It is my understanding that these radios require a license. I found a single motorola talkabout radio at Best Buy, but it has a 5-mile range capability. I ended up buying a 2-pair pack of the talkabouts that have a 2-mile range. If I return the 2 pair pack and get a single at the 5-mile range, will I need to apply for a license even if I am going to be communicating with someone at 2 or 3 mile range? |
#3
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Charlie,
Scott has an excellent reply. I'd like to point out that any handheld radio will start running out of steam at 5 or 6 miles. This is due to the lack of height of the transmitting antenna. As you know, a lot of folks put base station antennas up on towers. The reason being is that it gets the signal up away from nearby objects and also increases their distance to what is called 'radio horizon'. Radio horizon is the distance over flat ground (or water) from the transmitting (receiving) antenna to the point where the radio wave hits the ground/water due to the curvature of the earth. A simple formula to figure your range is take the height of the antenna from the ground (on an HT, 5 feet would likely be good as you're holding it up to your face) in feet (5 in this example). Double that number (10) and then take the square root (a bit over 3). That is the range of the radio to radio horizon. This will give you a bit over 3 miles. Now, as long as a second station's radio horizon overlaps or touches yours, you will have communications (assuming no big obstruction between you). The other station will have a bit over 3 miles. Added together, that means 6 miles is likely the limit (unless you climb a tree or something like that ![]() FRS is a bit more limited, but the batteries will last longer at lower power and the difference isn't going to be large under any normal circumstances. 73 from Rochester, NY Jim "Charlie" wrote in message m... I hope that this is the right newsgroup for posting this question. I wasn't sure where else to post it. I am looking for a single FRS type radio to communicate with a group of people who already have a radio. They are using motorola talkabout radios, and I think the model number is t5620. I know that the model number doesn't matter, just as long as the radio that I get has the subchannels that they are using. It is my understanding that these radios require a license. I found a single motorola talkabout radio at Best Buy, but it has a 5-mile range capability. I ended up buying a 2-pair pack of the talkabouts that have a 2-mile range. If I return the 2 pair pack and get a single at the 5-mile range, will I need to apply for a license even if I am going to be communicating with someone at 2 or 3 mile range? --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.502 / Virus Database: 300 - Release Date: 7/18/03 |
#4
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![]() Jim, In your example about range, the range wouldn't be 6 miles, it would 3 miles. The radius of the coverage area has to overlap the transmitter/receiver. So, if two radios each have a range of 3 miles that does not mean the total range between radios is 6 miles. 'Doc |
#5
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In , 'Doc wrote:
Jim, In your example about range, the range wouldn't be 6 miles, it would 3 miles. The radius of the coverage area has to overlap the transmitter/receiver. So, if two radios each have a range of 3 miles that does not mean the total range between radios is 6 miles. 'Doc In his example the range is limited by the curvature of the earth. That means if a person's eyes are five feet above the earth he can see the feet of someone three miles away, but he can also see the eyes of someone six miles away peeking over the horizon. So if the radios will talk line-of-sight, the range between them is six miles when they are both held five feet above the ground. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =----- |
#6
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![]() "Frank Gilliland" wrote in message ... In , 'Doc wrote: Jim, In your example about range, the range wouldn't be 6 miles, it would 3 miles. The radius of the coverage area has to overlap the transmitter/receiver. So, if two radios each have a range of 3 miles that does not mean the total range between radios is 6 miles. 'Doc In his example the range is limited by the curvature of the earth. That means if a person's eyes are five feet above the earth he can see the feet of someone three miles away, but he can also see the eyes of someone six miles away peeking over the horizon. So if the radios will talk line-of-sight, the range between them is six miles when they are both held five feet above the ground. Sorry Frank, you are wrong. Check the books again. |
#7
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Sorry, Doc. Frank's reply is exactly correct. As long as the two radio
horizons touch or intersect, communications will be established (assuming, of course, that the receivers work properly, the transmitters work properly, and the antennas work properly). My former neighbor now lives in Wellsville, some 80 miles away (110 or so by car) and can hear me just fine on the local repeater. Her elevation is around 2200 feet, which translates to a radio horizon of roughly 66 miles. One has to add the radio range of the repeater (which, incidentally, is located in the *opposite* direction from her) - the elevation is something like 500 feet (31 miles to radio horizon). 73 from Rochester, NY Jim "'Doc" wrote in message ... Jim, In your example about range, the range wouldn't be 6 miles, it would 3 miles. The radius of the coverage area has to overlap the transmitter/receiver. So, if two radios each have a range of 3 miles that does not mean the total range between radios is 6 miles. 'Doc --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.502 / Virus Database: 300 - Release Date: 7/18/03 |
#8
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![]() Jim, So, are you saying that range is unlimited at UHF as long as it's 'line of sight'? Assuming that the transmitter's output for both radios are the same, and both receiver's sensitivity is the same, and both have a usable range of 3 miles. That means for the two stations to hear each other they have to be within three miles of each other. At 6 miles neither will be able to hear the other because they would both be out of each other's usable range. Wouldn't matter what the 'line of sight' distance was. Propagation will make a difference, but we're talking about the 'normal', every day state of propagation. 'Doc |
#9
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Doc,
Normally, HTs will be limited to line of sight. The problem is that normal line of sight is only about 3 miles to radio horizon for a person standing on level ground. Get up on a ladder, and the horizon stretches out farther. We're not talking propagation enhancements, just a simple formula which takes the station's height above average terrain (in feet), double that and take the square root. The answer is the range to radio horizon. 5 feet (to a handheld antenna) times two is 10. SQR(10) is a bit over 3 miles. 6 or 7 miles max. Get in the second story of a house. Figure 11 feet (up a few feet to the first floor, another 8 or so to the second floor) and add that 5 feet from that floor to the HT. Now 16 doubled is 32. The square root of that is somewhat over 5. I would suspect a range of 10 to 12 miles between two handhelds equally elevated over average terrain in that case. I was on the 21st or 22nd floor of a high rise. Figure over 200 feet up, plus 600 feet above average terrain (yes, it was on a hill). 800 feet and I won't add the extra 5 feet. SQR(1600) yields 40 miles to radio horizon. Now figure in the repeater height. Should that repeater be up a total of 2000 feet (including hill, tower, antenna, whatever), it will have a range over 60 miles to its' horizon. As long as my horizon intersects its' horizon with no obstruction, I can use that repeater. The 3.5 watts on my HT is not a problem; my antenna gain is around 6 dBi and I'm sure the repeater antenna gain is way over 10 dBi. Plenty of power. I'm talking 24/7 communications. I've had a few chats over (and can raise at any time of day) the Toronto repeater. Definitely more than a couple of miles. Way more than a couple of dozen miles too ![]() 73 from Rochester, NY Jim "'Doc" wrote in message ... Jim, So, are you saying that range is unlimited at UHF as long as it's 'line of sight'? Assuming that the transmitter's output for both radios are the same, and both receiver's sensitivity is the same, and both have a usable range of 3 miles. That means for the two stations to hear each other they have to be within three miles of each other. At 6 miles neither will be able to hear the other because they would both be out of each other's usable range. Wouldn't matter what the 'line of sight' distance was. Propagation will make a difference, but we're talking about the 'normal', every day state of propagation. 'Doc --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.502 / Virus Database: 300 - Release Date: 7/18/03 |
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