View Full Version : Radio Comms
kalos72
09-10-2009, 03:16 PM
If my team has a manpack that has a range of say 30km, is there a way to setup a relay tower or something to extend the range of the radio to reach their "home base"?
Any restrictions or special circumstances I need to look for beyond the basic "how do you find and secure a large radio tower"...
Thanks...
Kellhound
09-10-2009, 06:11 PM
Directional antenna or very high place.
Or making a relay with two radios (connected so that what one receives is transmitted by the other) and leave them in the middle, in range with both, base and group.
Of course I'm thinking as a grunt carrying the old PRC77, not sure about newer models, experienced commo guys.
Nowhere Man 1966
09-12-2009, 03:41 PM
If my team has a manpack that has a range of say 30km, is there a way to setup a relay tower or something to extend the range of the radio to reach their "home base"?
Any restrictions or special circumstances I need to look for beyond the basic "how do you find and secure a large radio tower"...
Thanks...
Do you want this "repeater" to be omni-directional or do you just want it to beam the signal back to base? I know in the amateur radio world, I use repeaters a lot on VHF, the signal goes out in all directions. A lot of times, they would go beyond the 30 km range. There are also links too where you would have the omni-directional repeater linked up to another repeater or a control station, that link would most likely be directional and on other frequency.
I think what you would need is an omni-directional repeater at the area you're working in. You would use one frequency to access the repeater and another to listen. For example, when I use a local repeater here in Pittsburgh, I would set my walkie-talkie (or whatever) to transmit on the input frequency at 147.690 Mc and I would listen to the signal on 147.090. Mc, the latter signal covers a lot of range. Also if you want a directional radio/control link, you would use a third frequency or a second set of input/output frequencies, as links, say 224.26 Mc input, 224.86 output. There is a chain of repeaters I use from the Pittsburgh area that goes down past Washington DC that uses such a system.
Maybe II should draw a picture to explain it more.
Chuck M.
StainlessSteelCynic
09-12-2009, 07:17 PM
One thing that hasnt been mentioned is to use a larger antenna on the radio
Many military backpack radios from the 1960-1990s have a short-range antenna (short length, one-piece) and a longer range antenna (long length, several pieces) as part of their equipment but they can also be fitted with a much longer ranged antenna kit
This is basically a spool of wire and some cord to string it up btween trees or whatever is available. You unwind the spool to a certain length based upon the freq you're transmitting on and then hoist the whole lot up horizontal into the air and generally facing the area you wish to communicate with.
This page has an article about similar stuff. It's a long read but explains a bit (in plain language) about radio antennas and getting better range
http://www.swssec.com/ant.html
Nowhere Man 1966
09-16-2009, 08:51 PM
One thing that hasnt been mentioned is to use a larger antenna on the radio
Many military backpack radios from the 1960-1990s have a short-range antenna (short length, one-piece) and a longer range antenna (long length, several pieces) as part of their equipment but they can also be fitted with a much longer ranged antenna kit
This is basically a spool of wire and some cord to string it up btween trees or whatever is available. You unwind the spool to a certain length based upon the freq you're transmitting on and then hoist the whole lot up horizontal into the air and generally facing the area you wish to communicate with.
This page has an article about similar stuff. It's a long read but explains a bit (in plain language) about radio antennas and getting better range
http://www.swssec.com/ant.html
True, the most important part of the radio is the antenna. You can have the best radio in the world but with a terrible antenna, it will perform poorly. I only have a walkie-talkie as a ham radio but if I put a good antenna on it, I can make a 1 to 5 watt signal do wonders.
Chuck M.
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