GMRS coverage

[thekayakr]

Hello all,

New to GMRS and radio in general. I have the infamous Baofeng UR5+. Ive purchased the NA-771  antenna for one of them and the UT-72 mobile antenna for my truck. Me and the wife have been experimenting with them and not getting very good coverage. At 1 point I was on the roof while she drove just a short distance before losing her. 1.5 miles to be exact. So today (monday) we took them to work where I have access to a roof atop a 10 story building. I went to the roof (10th floor) with the NA-771 and she went to the 3rd (top) floor of her work with the rubber duck and we tried to talk with no luck. She then went outside to my truck and plugged into the UT-72 mobile antenna. A little static is all she got from me. I got nothing from her. This distance is less than 5 miles but right at it. I can see her work place practically. Cincinnati is in a bowl. I can see the ridge line that encircles the city. Basically our 275 loop I can fully see from that building which is 20 minutes in every direction. Ive already bought 3 radios and 2 additional antennas. I purchased over the weekend a roof top antenna that is specifically for GMRS 462mhz from Michael the J pole antenna guy. I was going to purchase the LMR400 cable but now Im hesitant in putting alot more money into this if its not really going get me the distance Im looking for in an emergency situation. I live in a suburb of Cincinnati and the majority of my family lives about 10 to 15 miles out in the country from me.

I want to buy a 50 watt base unit but Im afraid to sink more money into this if Im nonly going to get slim results. I read how peolple swapping their factory antenna for the ones Ive bought increases their coverage so much. Im not buying it or Im doing something terribly wrong, 

I only see 2 repeaters in Cincinnati and they have not given me permission yet. But from my limited understanding is if I cant even talk 1.5miles then how on earth can I reach a repeater thats 10 miles away or better?

Side note

I used the chirp to program the radios so they'd all be the same.

 

thx guys for any help.

Nice site by the way.  Very cool.

 

[WQYC236]

Wow, I'm new to the licensed side of GMRS also but those ranges seem awfully short.  From the top of the 10 story building you should be able to get 18 miles according to the "Line of Sight" calculator ( http://www.calculatoredge.com/electronics/lineofsight.htm). Hand held to mobile mag mount should be should be 5-6 miles if nothing is in between. I do it all the time with 5 watts over average forest and farm terrain with a pair of Terra walkie talkies with 15" antennas.

 

There's a spot (with both of us at ground level) where I talk to my friend after he gets off work a solid 12 miles away with MURS, walkies with car mag mounts...can't do  it on GMRS though. 

 

What you're trying to do sure seems possible. maybe others have the solution.

 

DH

[Logan5]

you could have interference in your area. faulty after market antenna? I am guessing you have TX set for High. something is defiantly wrong though. Building top to LOS building top is easy. Maybe faulty radio? I over see a dozen Baofeng/Pofeng radios and they all function very well. Never found a faulty unit.

[SteveC7010]

Double, double check your power setting for each and every channel on all radios.

[wrodina]

Try the rooftop-to-rooftop with both factory rubber ducks.

 

Double-check that you're both on the same channel, including the A/B setting.

 

Try a different channel.

 

Verify that both units can properly receive (use the NOAA weather frequencies in your area, they should be a good strong signal, although they are VHF).

 

Since you have 3 radios, try the range tests with all three (1 <-> 2, 1 <-> 3, 2 <-> 3). Also swap out the antennas that way to verify, once you know you've got good radios.

 

I've heard horror stories about the build quality of the Baofeng radios. I have a handful of them and so far they have been fine for my needs... but it may be something of a crapshoot.

[jvfreetage]

Sorry to be the one to say this, but unfortunately the Baofengs are not certified for part 95.  So basically they are not legal for GMRS use.  That being said...

 

The Nagoya 771 and the Nagoya 701 are GREAT antennas for Ham Use.  They're specifically tuned for the Ham bands.  I've noticed that trying to monitor GMRS and FRS using those antennas they are a little weak.  Baofeng Tech sells a Nagoya 701C which is tuned for commercial bands (which includes GMRS) and works GREAT.

 

Another thing to look for is that there are a LOT of "fake" 701'S and 771's out there.  You may have gotten one of those, especially if you paid less than $12-15 for one, because even though the 771 and 701 are tuned for Ham bands, they will work on the GMRS, just not as well as they do on the Ham bands.  

 

James

WQUL457

W8JVF

[Durake]

I can tell you I bought the NA-771 for my Wouxun HT and the same thing happened realized its not a GMRS Antenna! Its for Ham! 

 

Hope that helps?

[tobyD]

Hi

Lets say one of you are at a building top 50ft the other is in a mobile with hand held and outside antenna. So at 50 ft height the radio horizon is about 13.5 miles. That is about how far you should be able to talk to your truck, assuming not to much stuff in the way like buildings etc. If there is lots of obstructions then you may only see about 7.3 miles or so.

 

Yeah, something is wrong if you only get a mile or so. Also, when you go to use a repeater your signal is going more upwards toward the repeater antenna that is higher than the surrounding obstructions, no "stuff" in the way so your signal get there easier.

 

Hope this helps

 

Toby

WPVP844 / N5SIM

[Durake]

Wow, I'm new to the licensed side of GMRS also but those ranges seem awfully short.  From the top of the 10 story building you should be able to get 18 miles according to the "Line of Sight" calculator ( http://www.calculatoredge.com/electronics/lineofsight.htm). Hand held to mobile mag mount should be should be 5-6 miles if nothing is in between. I do it all the time with 5 watts over average forest and farm terrain with a pair of Terra walkie talkies with 15" antennas.

 

There's a spot (with both of us at ground level) where I talk to my friend after he gets off week a solid 12 miles away with MURS, walkies with car mag mounts...can't do  it on GMRS though. 

 

What you're trying to do sure seems possible. maybe other shave the solution.

 

DH

 

I could never get that one to work for me, or at least it never seemed like it was. I use http://www.solwise.co.uk/wireless-elevationtool.html for most of my coverage mappings. 

[WQYC236]

I could never get that one to work for me, or at least it never seemed like it was. I use http://www.solwise.co.uk/wireless-elevationtool.html for most of my coverage mappings. 

 

I understand, this is what I'm using now:  http://www.ve2dbe.com/rmonline.html

 

Although I'm finding it a little overly optimistic with what I'm seeing in the field but if you fine tune the antenna gain it comes pretty close to reality. 

[WQYC236]

I could never get that one to work for me, or at least it never seemed like it was. I use http://www.solwise.co.uk/wireless-elevationtool.html for most of my coverage mappings. 

 

That is a great tool that you sent! Thanks for posting!

[Durake]

That is a great tool that you sent! Thanks for posting!

I'm checking out the tool your using right now, the Radio Mobile Online  

[Durake]

I understand, this is what I'm using now:  http://www.ve2dbe.com/rmonline.html

 

Although I'm finding it a little overly optimistic with what I'm seeing in the field but if you fine tune the antenna gain it comes pretty close to reality. 

When I try to setup my coverage on my frequency it says "* Frequency not allowed for this account *" How could I put it on GMRS? Closest thing is 450

[n4gix]

"How could I put it on GMRS? Closest thing is 450?"

450.00 is as close as you can get. Honestly there isn't really much difference in a propagation map of 450.00 versus 467.00...

 

However, there is another propagation map generator here that will allow you to select a exact frequency. As long as you are fairly conservative in your input, you will receive a predictive coverage map that so far has proven itself as pretty accurate from my empirical tests in the real world:

http://lrcov.crc.ca/main/

 

In the example below, the colors are set as follows:

Light gray = HT coverage

Light blue = mobile coverage

Light red = sketchy at best for mobile, fairly good for a base station

 

Repeater is 467.675 40 watts at 42' on a 7.5 dB gain Comet CA-712EFC antenna.

 

BTW, unlike the other Canadian site, this map is generated almost instantaneously. I use both however using the same input data and compare them.

 

http://puu.sh/qZF3q.jpg

[jimndfw]

I have used this site http://wisp.heywhatsthat.com/ and found to be good one as well.

 

Show is gaps in certain areas, that were pretty much dead on.

[jmoylan69]

I would say to make certain that if you are using Nagoya Antenna's then id order them from nagoya. 

 

http://www.nagoya.com.tw/s/en/2/product/VHF-UHF-Ham-Radio-Handheld-Antenna-c66883.html

 

 

I've read many posts of people buying Baofeng's (pronounced POFUNG) thinking that theyre getting a legit radio. there are many counterfeit radios and antenna's. mostly with the antenna's. this is no different than using USB to UV5R programming cables. i went through 3 of them before i realized that Miklor had a review on the FTDI programming cables. used them and had not issues. this primarily if using CHIRP software. finally i said forget it. i ordered software from RTsystems for the UV5R and never had another issue programming.....NOT ONE!

 

 

Then i got the Nagoya NA-771 and i've even used it for GMRS with ease and vastly over 30 miles.  there are counterfeit antennas. and i think miklor or nagoya have a review showing the differences of the antennas and what to look for. they are NOT the same nor compatible. 

 

I on that same UV5R can sit in BatMtn and hit both the ham and GMRS repeater 14.3 and 16.54 miles away respectively on LOW power with EASE!!

 

SO FOR you to say you cannot reach anyone on simplex on high power only 5 mi away i have to inquire as to a couple of things.

 

Frequencies and freq step, is it matched for both radios?   if the radio is transmitting in narrow vs wide that will have a radical difference. made that mistake once.

 

is there a Rx PL setting on one radio and not the other?

 

then you other issues that could cause interference. how about the BIG ONE....WIRELESS ROUTERS NEAR YOUR RADIOS??   if a wireless router is near any of the radios. FORGET IT. ALL BETS ARE OFF.

[jmoylan69]

450.00 is as close as you can get. Honestly there isn't really much difference in a propagation map of 450.00 versus 467.00...

 

However, there is another propagation map generator here that will allow you to select a exact frequency. As long as you are fairly conservative in your input, you will receive a predictive coverage map that so far has proven itself as pretty accurate from my empirical tests in the real world:

http://lrcov.crc.ca/main/

 

In the example below, the colors are set as follows:

Light gray = HT coverage

Light blue = mobile coverage

Light red = sketchy at best for mobile, fairly good for a base station

 

Repeater is 467.675 40 watts at 42' on a 7.5 dB gain Comet CA-712EFC antenna.

 

BTW, unlike the other Canadian site, this map is generated almost instantaneously. I use both however using the same input data and compare them.

 

http://puu.sh/qZF3q.jpg

 

 

I could not get that to work at all for me.   id set the Tx Rx  pairs and it still tossed up an error.