FRS / GMRS Line Of Sight performance with cheap Motorola walkie-talkies

[ARCHIVED THREAD] - FRS / GMRS Line Of Sight performance with cheap Motorola walkie-talkies

Posted: 8/23/2009 3:06:20 PM EDT

A couple nights ago my SO and I decided to see how well a pair of Motorola $30 WalMart type walkie-talkies would perform from home to BOL over a line of sight distance [LOS] up to 14 miles.

She was on balcony most of the time, I was driving and trying to stay in contact.

To make a long story short, at the BOL, as long as we had LOS we had full quieting solid copy with slight reorientation of the radio body/antenna.

On the way to the mtn container, as long as there was what appeared to be almost LOS [it was dark] we had some commo.

Then we tried to see how signaling with a Fenix L2D [2 AA batteries] flashlight would work. She said it was bright ~14 miles away.

I think I will set up something with a remote control over IP or a simple radio link so I can blink a light from here at home.

Posted: 8/23/2009 3:36:28 PM EDT

[#1]

Optical line of sight? Laser LAN connection.

Posted: 8/23/2009 4:05:41 PM EDT

[#2]

Quoted:
Optical line of sight? Laser LAN connection.

5.8 gig is super fast and cheap. Thanks eBay...

Altho I did pick up some laser optical links in the mid 90's at a hamfest. Objective lens is about 5 inches, but I'm sure they are very slow.

Where would one find low cost fast ones to play with?

Posted: 8/23/2009 4:16:28 PM EDT

[#3]

I've have 3-4 sets of those over the years and I'm impressed you got a real 14mi out of them. Must be a better set than any of mine. Even in direct line of sight I've only got about half that and in the woods I get maybe a mile. I think they are great for keeping in communication with people that are already with you at your general location. If you have a few ache's of property they should be perfect to keep in touch. But if I'm at my campsite and my wife takes off in the RZR or quad, communication is gone pretty quick.

Posted: 8/23/2009 4:47:22 PM EDT

[#4]

Quoted:
I've have 3-4 sets of those over the years and I'm impressed you got a real 14mi out of them. Must be a better set than any of mine. Even in direct line of sight I've only got about half that and in the woods I get maybe a mile. I think they are great for keeping in communication with people that are already with you at your general location. If you have a few ache's of property they should be perfect to keep in touch. But if I'm at my campsite and my wife takes off in the RZR or quad, communication is gone pretty quick.

If you have true optical line of sight, the limiting factors are noise/interference and receiver sensitivity... in a remote area (low noise) you can go a long, long ways.

Posted: 8/23/2009 5:05:40 PM EDT

[#5]

Just want to mention, these Motorola W/T's were the 3 AA battery ones. They have the best legal power and we only buy the 3 battery AA ones. Usually Midlands, will have to test them the next time we split up.

We're also using the Tri Square 900 mc ones up here and I like those better since they are 'secure' [frequency hopping] and not every Tom, Dick, and Harry w/in 30 miles w/ a directional antenna can hear us.

The other day my SO went hiking and I was able to talk w/ her with the TriSquares about 3/4 mile away and it wasn't LOS. They will be more affected by terrain attenuation than the 460mc FRS radios.

The TriSquares offer a great opportunity [where legal] to be used in a 'secure' simplex repeater system.

Like this $60 one...

Posted: 8/23/2009 5:46:49 PM EDT

[#6]

You're BOL is only 14 miles away? [Better than mine (nonexistent) but seems a little close...]

Posted: 8/23/2009 6:31:09 PM EDT

[#7]

Quoted:
You're BOL is only 14 miles away? [Better than mine (nonexistent) but seems a little close...]

The important point is -14 miles from where?

Posted: 8/23/2009 6:57:38 PM EDT

[#8]

Quoted:

Quoted:
You're BOL is only 14 miles away? [Better than mine (nonexistent) but seems a little close...]

The important point is -14 miles from where?

I was hoping you would answer that, but you didn't, so 14 miles from where?

Posted: 8/23/2009 7:05:05 PM EDT

[#9]

Quoted:

Quoted:
You're BOL is only 14 miles away? [Better than mine (nonexistent) but seems a little close...]

The important point is -14 miles from where?

I was hoping you would answer that, but you didn't, so 14 miles from where?

I'd love to, but the Arfcom opsec... It's pretty nice, and a great investment if the econ doesn't collapse....

Posted: 8/23/2009 7:20:30 PM EDT

[#10]

Quoted:

Quoted:
You're BOL is only 14 miles away? [Better than mine (nonexistent) but seems a little close...]

The important point is -14 miles from where?

I was hoping you would answer that, but you didn't, so 14 miles from where?

I'd love to, but the Arfcom opsec... It's pretty nice, and a great investment if the econ doesn't collapse....

True. Hold on a second while I trace your IP.

Posted: 8/23/2009 7:47:45 PM EDT

[#11]

Quoted:

Quoted:
You're BOL is only 14 miles away? [Better than mine (nonexistent) but seems a little close...]

The important point is -14 miles from where?

I was hoping you would answer that, but you didn't, so 14 miles from where?

I'd love to, but the Arfcom opsec... It's pretty nice, and a great investment if the econ doesn't collapse....

True. Hold on a second while I trace your IP.

Oh, the noes!!!

Posted: 10/14/2009 4:27:55 AM EDT

[#12]

Anyone else run distance tests?

Posted: 10/14/2009 4:56:42 AM EDT

[#13]

14 mile flashlight visibility? C'mon....

No, really...c'mon.

Posted: 10/14/2009 7:16:41 PM EDT

[#14]

Quoted:
14 mile flashlight visibility? C'mon....

No, really...c'mon.

Yep, why not get out and try it. We've done it repeatedly now with a couple friends. Neat. We use Fenix lights.

Posted: 10/14/2009 8:15:09 PM EDT

[#15]

Quoted:
Anyone else run distance tests?

All the time but I sure can't get in line of sight distances like in this thread.

You could burn a house down 14 miles from here and not see the smoke let alone a light. My radios, hell its hard to find a mile that doesn't take you on the other side of a mountain.

Tj

Posted: 10/14/2009 9:38:10 PM EDT

[#16]

Quoted:
line of sight distance up to 14 miles.
She was on balcony most of the time

something doesn't add up here.

say the balcony is 20 feet up.
say you are in a vehicle 4 feet off the ground.

the RF LOS is only about 9 miles –– that's 6 miles to the horizon for her and 3 miles to the horizon for you.
due to RF diffraction, the radio horizon is approximately 1.3 times that, or only about 11.7 miles.

with gain antennas at both ends, i'd say it's marginal at best. now with omnidirectional rubber resistors?

Quoted:
signaling with a Fenix L2D [2 AA batteries] flashlight would work. She said it was bright ~14 miles away.

due to optical dispersion, i really have to doubt the "2AA's at 14 miles" assertion. looking downward, it is difficult, very difficult, to pick out an individual light point from an aircraft even 5 miles up –– and that is a straight shot up through the atmosphere, not at a right angle to thermal effects and through vastly increased airborne particle density (vapor, dust, smog, etc). maybe i'm missing something here, but a ~140 lumen light at 14 miles (of course assuming the horizon is cleared) is going to be mighty dim, even for nighttime-adjusted eyesight.

ar-jedi

http://www.ringbell.co.uk/info/hdist.htm
http://www.repeater-builder.com/antenna/radio-horizon.html
http://www.qsl.net/w4sat/horizon.htm
http://en.wikipedia.org/wiki/Radio_horizon

Posted: 10/15/2009 12:50:13 AM EDT

[#17]

Ive gotten 3 miles visibilty out of a tikka plus headlamp(read 5mm leds..aka not bright)..and it was quite obvious even at 3 mi!!

LED's have a tendancy to really throw.

Thanks for the test OP.. ive gotten some good distance as well.. 8mi LOS, no probelm.

Posted: 10/16/2009 10:04:25 AM EDT

[#18]

Quoted:

Quoted:
line of sight distance up to 14 miles.
She was on balcony most of the time

something doesn't add up here.

say the balcony is 20 feet up.
say you are in a vehicle 4 feet off the ground.

the RF LOS is only about 9 miles –– that's 6 miles to the horizon for her and 3 miles to the horizon for you.
due to RF diffraction, the radio horizon is approximately 1.3 times that, or only about 11.7 miles.

with gain antennas at both ends, i'd say it's marginal at best. now with omnidirectional rubber resistors?

Quoted:
signaling with a Fenix L2D [2 AA batteries] flashlight would work. She said it was bright ~14 miles away.

due to optical dispersion, i really have to doubt the "2AA's at 14 miles" assertion. looking downward, it is difficult, very difficult, to pick out an individual light point from an aircraft even 5 miles up –– and that is a straight shot up through the atmosphere, not at a right angle to thermal effects and through vastly increased airborne particle density (vapor, dust, smog, etc). maybe i'm missing something here, but a ~140 lumen light at 14 miles (of course assuming the horizon is cleared) is going to be mighty dim, even for nighttime-adjusted eyesight.

ar-jedi

http://www.ringbell.co.uk/info/hdist.htm
http://www.repeater-builder.com/antenna/radio-horizon.html
http://www.qsl.net/w4sat/horizon.htm
http://en.wikipedia.org/wiki/Radio_horizon

AJ, do you have mountains in NJ?

Posted: 10/16/2009 2:08:26 PM EDT

[#19]

I got some "Wireless Bridges", LOS that go 15-20 miles...cheap. Also have a one mile one unit, dont remember company name but I will find and post. Got reliable, fast ethernet connections to Barn, Shop and Chicken Houses... Not really critical for SHTF, other than the IP video survielence it can provide.

Posted: 10/16/2009 4:59:45 PM EDT

[#20]

Quoted:
I got some "Wireless Bridges", LOS that go 15-20 miles...cheap. Also have a one mile one unit, dont remember company name but I will find and post. Got reliable, fast ethernet connections to Barn, Shop and Chicken Houses... Not really critical for SHTF, other than the IP video survielence it can provide.

ACTUAL, last Fall when I was setting up an internet bridge to the mountains, same site as I discussed above, I was able to go the ~14 miles with 2 Linksys WAP54G's connected to 40 inch grid antennas but the speed was very slow. I may have used amps as part of the experiment, don't remember the setup. Even with amps the latency or something made the connection almost useless. This was the same path as the FRS and flashlight experiment.

I tried Tranzeos at 2.4 Gc and got modest speeds and finally bit the bullet and bought 5.8 gig Tranzeos. Speed [after finding out what router config settings was keeping it at ~ 3Mbps a few months ago by accident when my ISP was having wide area problems] is now as ~fast as my cable connection at my residence. Actually typing this using a 2 mile 2.4 gig Tranzeo link from the same location but speed is only ~2Mbps because the antenna on the res side is hidden and is 1/4 wavelength long with a metal vent cover screen shaped as a reflector.

Posted: 10/17/2009 10:59:26 AM EDT

[#21]

PLUS

= low tech, EMP proof LOS Comms WIN

Posted: 10/18/2009 2:05:25 PM EDT

[#22]

Now thats what I am talking about... Low tech..,.has worked for YEARS!!!!!!!!!!!!!!!!!!!!!!!

Posted: 10/25/2009 11:17:33 PM EDT

[#23]

FRS Range! AAR...

http://www.youtube.com/watch?v=8JMyxGPQxtU&feature=related

Posted: 10/26/2009 9:52:18 PM EDT

[#24]

Good read. Thanks for posting this.

We have similar radios and will have to do our own test in the future.

Posted: 11/3/2009 7:34:53 PM EDT

[#25]

Anyone use MURS radios? And if so which one?

Posted: 11/4/2009 2:37:20 PM EDT

[#26]

Quoted:
Anyone use MURS radios? And if so which one?

I rock old midlands that I got off ebay - not a cloged freq, and the radios are damn better than walmart - get extra batts, and hand mics...

Posted: 11/4/2009 3:24:09 PM EDT

[#27]

Quoted:
Anyone use MURS radios? And if so which one?

http://www.ar15.com/forums/topic.html?b=10&f=22&t=604623

see info/review on page 2:
http://www.ar15.com/forums/topic.html?b=10&f=22&t=604623&page=2#10338155

ar-jedi

Posted: 11/4/2009 4:36:52 PM EDT

[#28]

A few years ago I did a review on a Midland GXT635 GMRS with an 18 mile advertised range.
I did the test in Maine which is heavily wooded with numerous hills, it is anything but flat an open.
The best I could get out of them was 2-3 miles. Reception was very good until just before the
signal was lost and then bang you were out of touch.

I have not tried them here in Kansas but suspect they would likely do much better.......

Posted: 11/5/2009 6:01:19 PM EDT

[#29]

An aside to A-J's post re the vertex transceivers, I put a VHF repeater on the air yesterday [after much procrastination] and I'm running ~17 watts out the duplexer into a $29 Radio Shack scanner antenna and amazingly it's showing an excellent VSWR on a Bird 43 wattmeter.

[The antenna was quick and dirty and didn't take me away from other stuff and get hollered at]

To access/test it we went to town last evening and again tonight and can key it up and hear it with a little noise generally on the Vertex HX-370s [that I procrastinated ~2 yrs programming and it is super easy].

My problem is the transmitter is desense-ing the receiver [that shows a sensitivity w/ SINAD measurement at 12 db of ~.28 uv]. So when the work I have to do up there is finished and I can take time to fiddle w/ the repeater again, [coming weather window is the issue] I will try separating the xmitter and recvr and using separate antennas on both after verifiying the tuning of the duplexer notches. Won't take long to do it...

I have an old VHF isolator but don't know how they are supposed to be used with a duplexer to reduce desensing but heard they can IIRC.

Also, the Midland FRS radios that use 3 or 4 AA cells have given us excellent service and performance.

[ARCHIVED THREAD] - FRS / GMRS Line Of Sight performance with cheap Motorola walkie-talkies

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