The Science of PMR446 / FRS / GMRS Range: How Far Do They Really Go? (Retevis RB639)

Unlocking the secrets of walkie talkie and HT range testing with my latest video. Discover why these devices are mosttly reliable at under 500 metres, and how factors like a clear line of sight as well as elevation (say on a hilltop) can increase or degrade performance. Join us as we examine the science behind walkie talkie antenna gain, and see some real-time software modeling of range on a real map.
Featuring (Retevis RB639) - here's Fred's video: • Retevis RB639 PMR 446M...
Experience tells us that walkie talkies are mostly reliable at around 500 metres. However, sometimes you can get a greater range, for instance if you are in the clear or on top of a hill. We look at why this is, the software used to check the gain and we can even model the range over a live map. Tune in to understand.
The supplier tells me there is a deal here.. Here they are:
2 Pcs: www.amazon.co.uk/dp/B0BDR5XG6...
4 Pcs: www.amazon.co.uk/dp/B0BDR7B4C...
10 Pcs: www.amazon.co.uk/dp/B0BDR8HQS...
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[@M0RMY]

It's a shame we in UK don't have GMRS to the same extent as USA. I have had a load of fun with PMR though - perfect for biking holidays or walking with a group of friends. A good safety net and easy to show a newbie how to use one. Kids love them too.

[@DXCommanderHQ]

Great comment Tom.. Indeed, 50W with a decent antenna could be a lot of fun up around 450MHz for a £25 licence.

[@AndyWragg]

My Good friend and radio mentor/former boss Gary M0ONI bought a business lite license for our local emcomm group. We each have a bunch of BF-888's to give to local unlicensed volunteers. Quite useful for local co-ordination in the village. If we need to link the villages then we use our licensed gear.

[@TrullaCæmentarìí]

I just put up my own 50W GMRS repeater! This is such a great hobby! 73 CHEERS 🍻

[@DonzLockz]

Amasing results!

[@jameski5oeb668]

Great explanation of low power HT propagation! Thanks Cal!

[@nhaggin]

Great video, sir. Here in east-central Illinois, USA, the local GMRS users have started doing a weekly simplex net so everyone can experiment with his equipment. We've gotten scratchy but readable contact between two stations 35 miles apart, both with good antennas and 40 or 50 W power. Terrain is very flat around here so that works in our favor. I've done 6 miles simplex between me and my son using 5 W HTs, in good band conditions with a high-gain antenna on my end.

[@DXCommanderHQ]

Thanks for the info! Love the ideo of a weekly net..

[@seanwood8043]

Good stuff

[@mewrongway]

Very interesting video Callum! Thanks

[@DXCommanderHQ]

My pleasure!

[@seanwood8043]

Think of GMRS as channelized uhf CB like other country's have fewer channels more power and the use of fixed and mobile repeaters. And the use of call signs which keep everyone civil :) makes it a lot more usable for short range local communications. It shares channels with FRS unlicensed familily radio service for interoperability. FRS being very much like PMR 446 but a max power of 2 watts. Channels 8thru14 limited to 0.5 watts like PMR. Non removable antennas like PMR also. Original cb in the USA was uhf until the 23 channel Am/ssb 27mhz system was adopted. And later went to 40 channels and now allowing FM mode as well. Many tools in the chest for people to use as they see fit to me this is another great aspect of radio. And the people you get to share your interests with. It keeps the mind keen if you have the Radio Bug. Happy birthday to the DX Commander and thank you for what you have done and given back to radio. DX Commander Rocks everyone's Radios !

[@DXCommanderHQ]

Ah-ha.. I didn't know UHF preceeded CB on 27MHz. Very cool history.

[@Thomas-ZET]

Have several GMRS radios for the family , good for hunting as we have no cell service, it’s funny how they put on the box that you get 10 to 20 miles range, we are lucky to get half a mile

[@DXCommanderHQ]

Haha yes..

[@dougdaniels]

GMRS radios, at least in the US, can have removeable antennas (FRS can not), and there are some very good replacement antennas that will get relatively better TX/RX.

[@seanwood8043]

Repeaters and external antennas help considerably with gmrs. 50 watts thru a high gain antenna 30 feet up I achieve pretty good results. line of sight and hieght is name of the game in uhf. Repeaters are becoming more common in USA and can be linked to internet. 100 mile range is very possible in western US using linked repeater systems. Is is a evolving service ,Porta Rico has many out of need from storms and infrastructure problems with phones. Government has a large blimp they can deploy over island it has a high end ham and gmrs repeater on board big coverage after storms. Layers of different communication are always the best bet. HF however being the most consistent and reliable for the average guy. Bottom line rock your radios ;) .

[@DXCommanderHQ]

Yes, GMRS different ball-park.. I was going to spend more time on that - then though, "nah - it'll get muddy"!

[@joeblow8593]

I like the U.K. term "Lift Conditions" for describing for tropo conditions.

[@jackK5FIT]

Another very informative video. In the US FRS requires no license and 1/2 mile in a neighborhood around here is a good signal. GMRS shares some of the FRS frequencies but power can go up to 50w for a base station. A license is required but no test. 2 to 3 miles line of sight in the rolling hills with LOTS of trees is normal signal. Our club and ARES group is considering putting up a GMRS repeater for testing but coverage would require multiple repeaters because of terrain. Because of limited range in this terrain we stick with VHF/UHF Ham frequencies with lot of repeaters with antennas between 500 ft and 1000 ft. A friend made a GMRS contact 22 miles HT to HT but that's very unusual. Jack K5FIT

[@DXCommanderHQ]

Interesting comment Jack. It would be fun to have GMRS in the UK..

[@jackK5FIT]

@@DXCommanderHQ we are proposing to the County Sheriff that he request the installation of GPRS repeaters on the 5 county owned 500 ft towers and license his deputies because he wants backup radio possibilities between dispatch and the patrol cars. Of course they would be public repeaters. We'll see how that goes.

[@WillThePlank]

I’ve certainly never hooked up a CRT Micron UV to a roof mounted Diamond X30 to see how far I can chat to my currently unlicensed dad on his Baofeng UV-5R with a Retevis 771 antenna on PMR frequencies! And it certainly didn’t get a range of 5 miles on the lowest power settings while maxing out both S meters :p

[@DXCommanderHQ]

Yeah, TS-2000 and a V2000 is also good fun. I don't know how I know that though!

[@AndyWragg]

Hi Cal. As I'm sure Tom (Hello) will know, back in the (Army) Clansman days we used to use PRC349's on 70cms. If it was raining and you were in a wooded area you could basically forget any decent comms with them. Water is a great attenuator at those freqs.

[@M0RMY]

Hi Andy - indeed - coupled with a throat mic they were absolutely the DB''s (without the dog) !! Add in the weight and battery-life and the tacticool antenna - huzzahh!!! Marvellous (not). Really well made though and built like a tank (tanks have better comms inside!)

[@DXCommanderHQ]

Haha.. You guys! :)

[@genoa1979]

My first radio walky toky💪🏻❤️

[@g0fvt]

It is always difficult to predict the range of UHF handies, your synopsis was pretty accurate. Once in a while if you are on a hill, standing on one leg and have the wind behind you indeed you will get the odd contact at a surprising distance. A local ham whose HF antenna is within line of sight of mine often uses a 70cm handy, if I am using one too we might just about get scratchy comms If we are both at ground level.

[@DXCommanderHQ]

Yes, it can be a good laugh.. And lots of "scratchy"!!

[@1958johndeere620]

There was a huge push in my area with GMRS repeaters. A guy that own's a communications business with several commercial tower sites installed repeaters in his sites. Very little traffic unfortunately. I did get my license just for giggles. 35 bucks for 10 years.

[@DXCommanderHQ]

$35 for 10 years sounds an easy blast!

[@christophersmith1155]

I WISH FRS/GMRS WAS MORE POPULAR HERE IN THE USA. EUROPE HAS 0.5 or 1/2 OF A WATT. WE ARE ALLOWED 2 WATTS AND COULD REALLY BENEFIT AND ENJOY IT WITHOUT A LICENSE. ON GMRS WE ARE ALLOWED 5 WATTS ON CHANNELS 1-7 AND 50 WATTS ON CHANNELS 15-22 WITH A LICENSE.

[@RicArmstrong]

I'd love to hear your thoughts on those flat 'tactical' foldable antennas in UHF. How effective are they really?

[@DXCommanderHQ]

Yeah, they look VERY cool.. Never tried one (yet!)

[@mikeymouse4629]

If you are talking about the 'tape measure' type antennas like the ABBREE 48 inch AR-152 'Tactical Antenna', they work pretty well on 2M & 70CM, but do better on 2M, IMHO. SWR, next to the head is ~2.0 on 2M, & ~3.5 on 70CM. I can hit repeaters up to ~ 70 miles away from inside my house on 2M using 5 watts. UHF repeaters, not so distant - maybe 20 miles (very dependent on topography - 2M, less so). Using a hand mike with the unit on a belt clip takes the range on 2M down a bit - not much. Hope that helps.

[@Steven.Cartwright]

Im hearing people setting up PMR 446 homebase now in the UK? obviously not legal using 25 - 100watt radios and a 70cm antenna on the chimney but it sounds great to me. Is this going to be the next thing or has it come and gone?

[@DXCommanderHQ]

Yes.. Good fun. TS2000 at 50W and a V2000 :)

[@g4lmn-ron401]

£39, daft money really. I thought Fred was in my neck of the woods, Hertfordshire?

[@DXCommanderHQ]

Yes, I seem to remember MK way.. I can't remember. He did tell me a while ago on email..

[@2EOGIY]

2:47 holiday in Italy - Hello, can you hear me? boooooooommmmm (donut with the sprinkle and no colours) - I can hear you! boooooooommmmm (aurora borealis apeared in the shape of the donut in all colours)

[@DXCommanderHQ]

HAHA!!

[@johnchecketts1732]

The ones with removable antennas work best if you put them on a mobile antenna or base antenna

[@DXCommanderHQ]

Indeed!

[@tobyticehurst]

Hight is might on v/uhf and up, I believe Callum did an experiment with his collinear at different heights and the effects it has. If you were at a vantagepoint with a yagi at 12m on your PMR radio, you will achieve some surprising distance, which I imagine the guy in Norfolk had a similar setup. PRM at times is more active than 2m and 70cm with a bunch of friendly guys who enjoy playing radio just like Hams. I see PMR almost like the modern age CB.

[@DXCommanderHQ]

Oh yes.. That would be fun.. SSB and 40 feet with a Yagi on PMR446 :)

[@tobyticehurst]

@@DXCommanderHQ Some might say but cannot admit to seeing that in operation 😉.

[@gaptastic]

Form factor looks cool. BUT if in the USA, and ur buying gmrs radio, get a removable antenna. As ham operators we always buy an antenna to replace our rubber ducks, so you should do same for gmrs or any other band.

[@DXCommanderHQ]

Indeed. FRS and PMR446 (legally) apparently don't have the removable ones unfortunately.. But honestly, why would we buy one of those! :)

[@gaptastic]

@@DXCommanderHQ yeah ur prob right. The antenna would be more expensive than the radio.

[@TRIPPLEJAY00]

You got 150 miles on half watt. That's amazing. The line of sight is the best wat for sure.

[@DXCommanderHQ]

Conditions I guess..

[@supertorqued72]

Nice job... I expected to hear about the curvature of the earth and escapement of the signals through the atmosphere. Being LOS the signal will continue straight as the earth curves away from it. Therefore on a flat desert you're still limited on your range.

[@DXCommanderHQ]

Haha.. Yes, I need to make a video about that actually.. The earth curves more than we think! Good point.

[@supertorqued72]

@@DXCommanderHQ I look forward to seeing it. 😁 -KJ7SNW

[@basshorseman998]

If that indeed a Fender P bass on the wall? and what time tomorrow good Sir?

[@DXCommanderHQ]

12:00 UTC. Yes, guitar copies..

[@johnchecketts1732]

Cb radio is just as good and thar are still quite a lot of people using it for radio communication especially the radios with ssb on them

[@plaws0]

US FRS channels were "stolen" (lol) from GMRS and are all in the 462/467 MHz range. FRS - license by rule; GMRS - license by paying a fee (higher power, repeaters allowed). GMRS was, long ago, "Class A Citizens Band" (mostly - GMRS people deny it!)

[@DXCommanderHQ]

Class-A CB.. Love it :)

[@ontopoftheroof]

Are you sure he didn't say he was "from" Norfolk? 😃

[@DXCommanderHQ]

No idea..

[@bassangler73]

Like you said they are great for friends and family...it keeps you off the 2 meter ham bands with just normal family and friend chat...Plus it's radio, so that automatically makes it cool

[@DXCommanderHQ]

Yes!

[@paulw8652]

Have you seen Andy Kirby’s stuff on this

[@DXCommanderHQ]

Andy likes 11m and stuff like this, yes :)

[@paulw8652]

@@DXCommanderHQ we’re all in it for the radio

[@the_mad_swimbaiter455]

How do you know it's not in colors Cal? Maybe aliens can see RF? Bahahaha, just being silly. Fun video.

[@DXCommanderHQ]

Good point! LOL!!!

[@bobdole57]

Our favorite garbage radios here are Baofengs

[@TrullaCæmentarìí]

THANK YOU CAL FOR ALL YOU DO! 73 de N3JDK

[@DXCommanderHQ]

Yeah! Thanks for stopping by!