Does Power Output Matter? (Hint: NO!)

[OffRoaderX]

When transmitting on an HT and using the HT rubber-ducky antenna, power output on GMRS or 70cm does not matter when in the range of 2 to 10 watts!

...change my mind....

[WRYZ926]

6 minutes ago, WRTC928 said:

The physics of UHF RF waves suggests there may sometimes be things attenuating your signal which could be overcome by a few more watts. The only time I've personally seen it matter was trying to hit a repeater from inside my house with a stubby antenna. (It was just an experiment to satisfy my curiosity.) On 5 watts, I could open the repeater but couldn't be understood. On 10 watts, I could be understood but with a weak signal and a lot of noise. Outside the house or with a better antenna, there didn't seem to be any discernable difference. So, yeah, it might matter...sometimes...maybe.

I did a similar experiment using 20 watts and 50 watts on my base radio and Comet CA-712EFC. There is a GMRS repeater about 50-55 miles straight line distance from me. I could get in and was heard at 20 watts but had lots of static/noise. Switching to 50 watts made all the difference. The extra 30 watts didn't get me any more FARZ but it did make my signal clearer.

It's not going to make much difference between 2, 5, or 10 watts with an HT when everything else is equal. 

One has to quadruple the output power to gain 1 S unit (6dB). And most people won't be able to hear the difference in 1 S unit.

[marcspaz]

I'm not sure the mobile comparisons are a realistic comparison for the original statement of:

• A handheld
• UHF frequencies between 440MHz and 470MHz
• 2 watts compared to 10 watts

HT performance characteristics are significantly different because of the form-factor, antenna design and size, and several other conditions that make it unreasonable to compare them to a mobile radio.

We really need someone with an HT that is capable of both 2w and 10w.  I have an HT that outputs 0.5w and 4w (about 9dB), but still not 2w and 10w (about 7dB).

[WRXB215]

Trees.

[marcspaz]

There's always one guy. LoL

 

Under perfect conditions, best case, it's 1 S-unit. I would say while there is a measurable difference, there's no difference in practical application.

 

So... I agree.

[UncleYoda]

I'm 3000mi from you so proof isn't possible.  But, the best answer I can think of are the power level settings on my Yaesu mobile: 5W, 10W, 30W, 75W.  Doubling (or more) the power at each step can make a difference of whether the signal is copy-able or how strong/loud it sounds based on distance and intervening terrain.  Years ago I did compare FRS bubble-pack radios to old Cobra 2W GMRS radios with stock, short antenna and the Cobras were better (good signal 1/2-3/4 mi.)

 

Note: I used the ham radio for an example because my DB20G in GMRS mode has no power adjustment.  Haven't done any tests on my GMRS HTs (UV5G) because they're good enough.

[WRYZ926]

Definitely not enough difference between 2 watts and 10 watts when using a HT for anyone to notice. 

Now I have held my cane up in the air while using a HT and cell phone and have occasionally seen a slight improvement. But I have to point the cane towards the tower no notice any change.  

 

As mentioned, UHF frequencies do not get along with trees, especially evergreen trees. 

 

[WRTC928]

The physics of UHF RF waves suggests there may sometimes be things attenuating your signal which could be overcome by a few more watts. The only time I've personally seen it matter was trying to hit a repeater from inside my house with a stubby antenna. (It was just an experiment to satisfy my curiosity.) On 5 watts, I could open the repeater but couldn't be understood. On 10 watts, I could be understood but with a weak signal and a lot of noise. Outside the house or with a better antenna, there didn't seem to be any discernable difference. So, yeah, it might matter...sometimes...maybe.

[LeoG]

Not exactly the same thing but I have a Comet CA712EFC at the house and was using a Wouxun XS-KG20G+ which puts out 25 watts and to my repeater at my shop with a 7.2dBi Retevis antenna through 1.6KM of thick dense trees and it was hit or miss almost all the time.  I switched up to a 50 watt KG1000+ and it's R7 or better all the time. 3dB difference in power level.

I have a Tidradio H3 that puts out 4.7watts and a Baofeng UV26 that puts out 9.7 watts.  I have a spot near my house behind a church that the H3 can't ping my repeater from whereas the UV26 will ping it with ease.  But it doesn't matter neither can get any modulation through the repeater at that spot.  But the wattage difference does allow the repeater to hear one and not the other.

[WRTC928]

4 minutes ago, WRYZ926 said:

I did a similar experiment using 20 watts and 50 watts on my base radio and Comet CA-712EFC. There is a GMRS repeater about 50-55 miles straight line distance from me. I could get in and was heard at 20 watts but had lots of static/noise. Switching to 50 watts made all the difference. The extra 30 watts didn't get me any more FARZ but it did make my signal clearer.

In my car, I have an AnyTone AT-5888UVIII (nominally 50 watts) feeding a Metropolitan tri-band (144/220/440) antenna. I've measured the output on the radio at 5, 12, 28, and 40 watts on UHF. To the GMRS repeater at my house, 5 watts and 12 doesn't seem to matter, but 28 gets me 2-3 more miles in some locations. I don't recall finding a difference between 28 and 40 in most locations; however, when I dip down into the river valley, only 40 watts will get me there. That's my very unscientific study. I have a different radio (TYT TH-9800D) in the truck and an SG7900 "Super Gainer" antenna. I haven't measured the output of the radio, but it's likely about the same. With that antenna, it seems to be pretty much "all or nothing". I do get more farz than with the little Metropolitan antenna, though (unsurprisingly).

 

21 minutes ago, WRYZ926 said:

It's not going to make much difference between 2, 5, or 10 watts with an HT when everything else is equal. 

One has to quadruple the output power to gain 1 S unit (6dB). And most people won't be able to hear the difference in 1 S unit.

As noted above, I did find one situation where the difference between 5 and 10 watts was able to overcome the attenuation of my walls using a really suboptimal antenna. Always remember to never say always or never.

[WRUW493]

This is why RF engineers use dBm instead of watts. An additional 5 watts starting from 5 watts is 3dB. But an additional 5 watts starting from 50 watts is 0.4dB. The former is noticeable, the later is not. The traditional "S-unit" is chosen to be a difference of 6dB, which is usually considered the increase in power necessary to be a meaningful increase. Or at least enough of an increase that the RX signal strength is enough stronger to be worth the extra (insert here: antenna gain, TX power increase, etc). 

I can't find it now, but the FM receiver parameter called "rise" is a measure of how high the signal is above the RX noise floor has to be to achieve a desired signal to noise ratio, ie SINAD. This is not a linear curve as in an extra 1dB in "rise" does not equate to an extra 1dB in SINAD. So here again, RF engineers like the dBm power metric as it lends itself to speaking of a change in "rise" more easily. 

Hope this helps.

 

[WRYZ926]

7 minutes ago, marcspaz said:

I'm not sure the mobile comparisons are a realistic comparison for the original statement of

You are correct that the mobiles aren't a good comparison to hand held radios. But it does show that even going from 20 watts to 50 watts does not make a big difference.

Hand held use short and very compromised antennas that aren't very high above the ground. Line of site will make more of a difference than 2 watts versus 10 watts.

Here is a question to ponder. Will a hand held work better if used by a big person compared to a skinny person? 

 I ask since our bodies act as part of the ground plane when using a hand held radio.

[hxpx]

32 minutes ago, marcspaz said:

We really need someone with an HT that is capable of both 2w and 10w.  I have an HT that outputs 0.5w and 4w (about 9dB), but still not 2w and 10w (about 7dB).

Anyone have a TD-H8? The manual doesn't say what the low/med/high power levels but I saw somewhere the low is 2W. Might be a good test radio. The TD-H3 only has low/high and mine is 1W/5W.

Rocky Talkie released a video showing how their 2W and 5W radios performed with obstructions - both performed similarly with minor obstructions (more static with 2W but still understandable) and major obstructions/foliage significantly reduced the range of both with 5W doing a little better. It's a marketing video, though, so... grain of salt and all that.

[UncleYoda]

HTs can be set up as base stations.  Antenna type isn't specified in the OP.

[marcspaz]

@hxpx I measured my TD-H3 on a calibrated meter and got the 0.5w and 4w... so the TIDRadio advertising is very accurate. I was pleasantly surprised. 

 

7 minutes ago, UncleYoda said:

HTs can be set up as base stations.  Antenna type isn't specified in the OP.

It's assumed based on the framing of the question. 

[73blazer]

In most cases I would agree. There are cases where it definitely helps however and I have tested this personally with many different radios.  The case I'm talking about is heavy rolling forest, which just happens to be where I live and also where I hunt, hike, camp....I'm not talking a few trees sprinkled around some suburban homes, or a line of trees flanked by fields/open areas, or a lightly forested park,  forest, real dense ~70' canopy height  forest, many square miles of it. . All the 3-4w radios, even some Kenwood and Yeasu, Btech, baeofang, you name it...,  won't do more than 1/2-3/4mi mabey 1mi if your lucky in this condition on 70cm/GMRS/UHF even with a 771G on them. . While the 5.5w 935g or 5w 905G,  does~ 1.5mi with perfect clarity, a little more with a 771G, or with stock antenna with some light static.  An 10W retivus RT29  (real output on GMRS 16 was 7.2w)  did the 1.5mi or a little more,  but it's audio quality even when only 100 yards away in open field sucked so bad I didn't know how to qualify it.

You've said this many times in here and on your videos, I doubt I'll change your mind, you kinda half acknowledged it however, as I recall in one older video I remember the words something like "may help with ....penetration....penetration" accompanied by a twisting forearm thru hand gesture, so you thought it may help at one point. My real world experience tells me certain what most may consider to be edge cases, it indeed helps. In most cases in most areas, yes, it doesn't matter much.

[SteveShannon]

16 hours ago, OffRoaderX said:

When transmitting on an HT and using the HT rubber-ducky antenna, power output on GMRS or 70cm does not matter when in the range of 2 to 10 watts!

...change my mind....

Does not matter in what way?  Range? Clarity of reception within that range?
I agree that in the open, two watt handhelds with a rubber duck antenna will transmit clearly as far as the curvature of the earth will allow.

But if transmitting from inside some attenuating material, such as vegetation or even a building or vehicle, the extra 7 dB of power can make a perceptible difference.

[nokones]

I did a test once between 4 watts and 60 watts with same radios in the same stationary position there was barely any noticeable difference.

[OffRoaderX]

1 hour ago, 73blazer said:

....penetration....penetration

 

[OffRoaderX]

20 minutes ago, nokones said:

I did a test once between 4 watts and 60 watts with same radios in the same stationary position there was barely any noticeable difference.

I did the same thing when i did my distance personal best when hitting a repeater at 92 miles.. I could barely hit it, but when switching between 40W and 110W, it made no difference at all - people listening reported 0 change. 

[dosw]

12 hours ago, marcspaz said:

I'm not sure the mobile comparisons are a realistic comparison for the original statement of:

• A handheld
• UHF frequencies between 440MHz and 470MHz
• 2 watts compared to 10 watts

HT performance characteristics are significantly different because of the form-factor, antenna design and size, and several other conditions that make it unreasonable to compare them to a mobile radio.

We really need someone with an HT that is capable of both 2w and 10w.  I have an HT that outputs 0.5w and 4w (about 9dB), but still not 2w and 10w (about 7dB).

I have an AR-5RM that will do 2w and 10w. I have a 701 style rubber duck, and a 771 style. And adapters to hook up to a variety of mobile antennas. And I can set up a radio at home to record into a VOX-activated recorder. So I think I have all the tools necessary to perform this test from a variety of locations around my city.

I can say that I've done similar tests in the past, and that at the fringes, things will get more scratchy at 2w than at 10, but that other factors are more important such as not sitting IN the car with the rubber duck antenna, and not having my signal blocked by terrain. In such situations, being in the car vs out of the car can make the difference of getting a recording to take place (ie, squelch breaking on the radio at home) and not getting through at all. Power has only ever made the transmission a little clearer, better quieting, and only at fringe areas.

But I'm happy to run the test with this specific equipment. I'll have some results Saturday. Ideally I'll be able to post the recordings and others can decide if they constitute proof or disproof.

[nokones]

1 minute ago, OffRoaderX said:

I did the same thing when i did my distance personal best when hitting a repeater at 92 miles.. I could barely hit it, but when switching between 40W and 110W, it made no difference at all - people listening reported 0 change. 

The signal level difference between 4 watts to 60 watts is barely a 4 dB increase in signal level. It is my understanding that it takes at least 6 dBs to make any significant difference.

[nokones]

It really makes no difference if the tests are done in the car or building or outside the car of the building insofar as testing the differences. The signal level differences between the two test sample power levels won't be changed by any measurable amount between the two signals.

Yes, outside will get you more farz for both power levels.

In my case with a difference of between 4 watts and 60 watts, it is still a tad less than 4 dBs and that difference of less than 4 dBs of signal level won't change rather if you are outside or inside.

You still need to deal with the signal-to-noise ratio.

[LeoG]

Line of sight you won't see a huge difference most of the time.  It always comes down to when something is in your way.  And the state I'm in is full of trees and hills and small mountains.  The attenuation factor of the trees winter vs summer is something fierce.  Signals in the winter making it with ease and those same setups in the summer not being able to touch the repeater.

Did a job that was an hour away and in the winter I could talk with my wife most of the time through the Glastonbury repeater.  As the leaves got on the trees my signal got much worse and I could only contact her sometimes instead of most of the times.  I'll bet if I changed out from my 20w to a 50w it might have made a difference.  Only because I know I was right on the edge.

[nokones]

....penetration....penetration

 

with or without lubrication, it won't change the price of noodles in Pandaland

[SteveShannon]

10 hours ago, nokones said:

The signal level difference between 4 watts to 60 watts is barely a 4 dB increase in signal level. It is my understanding that it takes at least 6 dBs to make any significant difference.

4 to 60 watts is nearly 11 dB. (4 to 40 is 10 dB).