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GMRS / FRS Discussions related to GMRS (General Mobile Radio Service) and FRS (Family Radio Service) communications

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  #1 (permalink)  
Old 07-25-2014, 4:05 PM
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Default Just curious............

I see frs/gmrs units advertised with ranges of 16 miles, 24 miles, 30 miles and 36 miles and so forth.
I usually see the 36 mile range tied to about 4 - 5 watts ERP. Some manufactures won't or don't advertise their unit's ERP.
Is there a rough estimate of ERP for these range claims?
For example what would a range claim of 24 miles translate into for ERP?
I know the range claims are wildly over stated.
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Old 07-25-2014, 10:26 PM
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I've talked 15 miles before on FRS radios. But, it was line of sight over top of a valley. Both of us about 100 feet above the valley floor. I regularly hear blister packs from 10-12 miles away that, are transmitting from the valley floor. I don't know how to give a direct answer to your question.
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Old 07-26-2014, 12:14 PM
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Default that is one

you just gave one answer.
with nothing in between you can get a good distance.
down here in flat florida an old girlfriend and myself would get around 1 to 2 miles on the highway.
more 1 than 2. but it was just for fun.
when used around the house the kids had to stay in the neighborhood, about 1/4 mile tops.
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Old 07-27-2014, 12:06 AM
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I would check here OET -- FCC ID Search using the fcc id number found on the back of the radio or battery compartment.
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Old 07-27-2014, 1:17 AM
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Using UHF CCR's at 2 watts we can get 3ish miles in the mtns.
As for transmitted signal strength vs distance, here is the best way I know to splain it.
Remember the old CB's with the analog meters? If you are hearing me at a 5 on the meter, I would have to 4x my output to put a 6 on your meter. To make it a 7, it is another 4x. So in the above example, 4 watt was 5db, 16 watts made 6db, 64 watts pushed it to 7db. Now if I want to make it 8db I'll need to transmit at 256 watts.
Does that make sense? hope so. I really am a poor teacher....
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Old 07-29-2014, 4:08 PM
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Thanks for the link to the FCC website.
This is what I was able to piece together (sort of):
If the manufacturer claims 16 miles - about 1/2 watt
If the manufacturer claims 24 miles - about 1 watt
If the manufacturer claims 30 miles - about 2 or 3 watts
If the manufacturer claims 36 or more miles - about 5 watts.

This is what I pieced together using the manufactures exagerated clames of range actual test results posted on the FCC website.
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Old 07-30-2014, 8:58 AM
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They can print anything they want on the package and it makes no difference. Nobody is penalizing them for their deceptive practices. In other words, they're not doing it on a mile per mW ratio, it's all just bullfish. It's probably more to do with a mile per $ ratio.
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Old 07-30-2014, 11:18 AM
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Quote:
Originally Posted by rapidcharger View Post
They can print anything they want on the package and it makes no difference. Nobody is penalizing them for their deceptive practices. In other words, they're not doing it on a mile per mW ratio, it's all just bullfish. It's probably more to do with a mile per $ ratio.
Fully agree!

There is no way with this type of service and equipment to simply equate power to range. Everything matters; terrain, distance, atmospheric conditions, and more. That can not be summarized on the packaging.
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Old 07-30-2014, 12:35 PM
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I agree fully with everything that RAPIDCHARGER said. I was just trying to see if there was any connection between the manufacture's outlandish range claims and the actual tested power output. I've reviewed a few differnt manufactures and their bogus range claims. Then I went to the FCC website and checked tested results for the same product and there does seem to be some consistecy between different manufactures.
I agree fully that range claims are bull. My original thought was,"Why would all the manufactures greatly over state the range of thier devices?" And secondly,"Is there a pattern?"
It seems so.
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Old 07-30-2014, 4:09 PM
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I've talked 15 miles on FRS. Of course... I was standing on an 8000' mountain at the time. ;-)
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Old 07-30-2014, 5:13 PM
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Just to be clear, I was not supporting the manfacturer claim of big distance on half a watt. It can almost be done. Not reliably. And very noisy. Experimental only.

Sent from my SCH-I535 using Tapatalk 2
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Old 07-30-2014, 5:28 PM
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Quote:
Originally Posted by blastco2 View Post
Just to be clear, I was not supporting the manfacturer claim of big distance on half a watt. It can almost be done. Not reliably. And very noisy. Experimental only.

Sent from my SCH-I535 using Tapatalk 2
Well, from my location I can get a noise free signal out of a repeater twenty miles north of me with 1/4 watt output. This is on a VHF Ham band, of course, not UHF. But it's not JUST power.
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Old 07-30-2014, 5:55 PM
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No one is putting out 5W ERP on GMRS/FRS hand-held radios. About the max is a little over 2W ERP (some claim 5W, but that is conducted power, not ERP...roughly the power coming out of the battery pack, not coming out of the antenna).

Open field distance (i.e. no obstructions) is a factor of both transmit power and receive sensitivity. We routinely got 50 miles in testing from ~2W with the GMR5089, GMR5099, and GMR6000 radios. But, these tests are conducted from the top of Mt. Scott in Oklahoma southward beyond the Red River.

Real achievable range is more a factor of line-of-sight distances. Any obstruction will limit the range. Going over the horizon is going to kill any reception (barring a large reflecting surface, and that would be spotty). To get better range, raise your antenna by getting to the highest point you can in your immediate area.

To get the ERP, you need to be reading the SAR report for the model on the FCC's web site.
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Old 07-30-2014, 5:56 PM
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I can remember back in the late 50's, (now I'm showing my age), my father purchased a UHF converter to receive the NEW TV CHANNELS above channel on 13 our standard 13 channel TV. And I remember the reception was very 'SPOTTY', just a slight movement of the "rabbit ears" could mean static or clear reception @ 10 miles! I'm sure these xmitters were using a whole lot more than 5 watts.
This is why I started this thread.
Most people know UHF is LOS (line of sight), How can these companies make a claim of 36 - 40 miles @ 5 watts ERP?
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Old 07-30-2014, 8:28 PM
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Quote:
Originally Posted by tomatohead View Post
I agree fully with everything that RAPIDCHARGER said. I was just trying to see if there was any connection between the manufacture's outlandish range claims and the actual tested power output. I've reviewed a few differnt manufactures and their bogus range claims. Then I went to the FCC website and checked tested results for the same product and there does seem to be some consistecy between different manufactures.
I agree fully that range claims are bull. My original thought was,"Why would all the manufactures greatly over state the range of thier devices?" And secondly,"Is there a pattern?"
It seems so.
Well, I think it is more of an issue of "one upmanship" Marketers need to brag higher ranges than their competors. Also, they one up themselves by claiming greater range on their higher priced models, looking for a sale.

On FRS/GMRS I've averaged about 3/4 of a mile on many different brands/power levels.

This is comparable to two 70 cm handhelds on 5 watts. Power isn't the issue. Antenna quality/height is, as well as any geographic/natural obstacles. This is in suburban environments.

I've used and reviewed FRS radios since day one. On GMRS, I haven't looked at anything lately, since I let my license lapse once I got my amateur license.
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Old 07-31-2014, 4:31 PM
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Default FRS/GMRS range.

As with previous posters, there is so much marketing hype on range. I have noticed that the Motorola and Cobra ones seem to have clearer audio than the Uniden and odd named models.

Also the Garmin Rino 120 had a better radio inside than my newer Rino 530. The Rino 120 has a light green backlight behind its grayscale screen and could be seen through night vision also.

As for range, they all seemed to work reliably out to 1/2 to 1 mile in FRS mode, and the few times I have used GMRS, it may have extended range slightly.

Often times there is the hype of "Extended Range Mode" where the radio uses a higher power, which just depletes the battery faster.

My best range was on a 7 thousand foot high hill in Afghanistan, talking to an aircraft about 20-22 miles away. This was with the Garmin Rino 120 I had at that time. It later broke on that mission and Garmin gave me a new one for my troubles.
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Old 07-31-2014, 6:08 PM
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I have a Uniden GMRS/FRS combo radio. It defiantly puts out 5 watts. It gets the same range as my Motorola public safety gear.
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Old 07-31-2014, 7:48 PM
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duplicate.
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Old 07-31-2014, 7:50 PM
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Quote:
Originally Posted by UPMan View Post
No one is putting out 5W ERP on GMRS/FRS hand-held radios. About the max is a little over 2W ERP (some claim 5W, but that is conducted power, not ERP...roughly the power coming out of the battery pack, not coming out of the antenna).

Open field distance (i.e. no obstructions) is a factor of both transmit power and receive sensitivity. We routinely got 50 miles in testing from ~2W with the GMR5089, GMR5099, and GMR6000 radios. But, these tests are conducted from the top of Mt. Scott in Oklahoma southward beyond the Red River.

Real achievable range is more a factor of line-of-sight distances. Any obstruction will limit the range. Going over the horizon is going to kill any reception (barring a large reflecting surface, and that would be spotty). To get better range, raise your antenna by getting to the highest point you can in your immediate area.

To get the ERP, you need to be reading the SAR report for the model on the FCC's web site.
Those are Uniden branded radios and they are marketed as "50 miles range"
Since you obviously know those results are not typical and 100% of buyers will not be using the product to talk from Mt. Scott southward beyond the Red River, how can you sleep at night deceiving buyers like that?

It's like advertising a car that gets 1000 mpg so long as you're rolling down a hill with the engine turned off. If you had something to do with these unrealistic claims on the packaging, then you ought to be ashamed of yourself. Especially when you know full well actual range will be 100 times less. Shame on you.
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Old 07-31-2014, 8:12 PM
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Quote:
Originally Posted by rapidcharger View Post

It's like advertising a car that gets 1000 mpg so long as you're rolling down a hill with the engine turned off. If you had something to do with these unrealistic claims on the packaging, then you ought to be ashamed of yourself. Especially when you know full well actual range will be 100 times less. Shame on you.
I totally agree, and very appropriate analogy. Many automakers, both "imported from Detroit" and "foreign" have been sued by the FTC for overstating their MPGs on many models.

It is long time the industry adopt some real standards and post HONEST, REAL WORLD range expectations and stop with this intentional misleading puffery. It is deceptive and misleading.

Now I am sure the average ham or radio professionals know it is entirely possible under ideal conditions to achieve portable to portable communications over a "36 mile" distance from a 4,000 foot mountaintop or flying around in a chopper, but I even call to question the validity of these tests. The average FRS/GMRS bubble pack has a craptastic single chip radio base with no front end and a horrible inefficient antenna. I know I can hike up to the top of Kennesaw mountain with an APX7000 and talk across Atlanta to another LMR portable, but trying this with (insert your manufacturer of cheap bubble pack FRS/GMRS radios here) and you'll be lucky to talk into Marietta 5 miles away and actually be able to receive the station you are talking to.

The electronics industry needs an enema the way that they did back in the 1970s with overstating audio power amplifier specifications. What Uniden, Cobra and others do with these "35 mile range" claims is akin to the "300 watts music power" that some Hong Kong stereo manufacturers did putting these figures on a $99 stereo receiver that had some limp single Darlington IC that could barely spit out 12 watts per channel at 10 percent THD.

And IMO, this "GMRS/FRS" combo radio should have never been allowed to leave the gate. So many unlicensed users causing interference to licensed GMRS stations and repeater users.

Shame on these sleazy manufacturers, all of them.
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