Difference between 0.5W and 3W

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Powermax
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Difference between 0.5W and 3W

Post by Powermax » 01 Apr 2015, 10:21

I have a couple of TTI 1446 PMR radios which apparently are able to be modified to 3W by a 'simple' soldering procedure.

However, it doesn't look simple to me as the circuit board is tiny of course and one slip of the hand with the iron could ruin it.

So the question I am asking is, would it be worth the risk? How much difference will I see if I jump to 3W?

a) in a standard built up area
b) on top of a hill with a view of 50 miles

I already have a 'better' antenna - a Nayogi 771, which is noticeably better on TX than the pen spring which is shipped with the set.

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Re: Difference between 0.5W and 3W

Post by mm3oqr » 01 Apr 2015, 11:00

a) in a standard built up area - virtually nothing.
b) on top of a hill with a view of 50 miles - it will make a difference there, but unless the person you are talking to is also using similar power then you may not hear them reply.

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Re: Difference between 0.5W and 3W

Post by Mitch » 01 Apr 2015, 11:10

^^ I agree with the above.
You might get double the range if you're lucky but in the reality it won't make as much difference as you think. The biggest drawback is the batteries, they'll get hammered and be flat in no time, so overall not so good imho.

If you want more power get a cheap Chinese handy or two then you can have a play and compare one to the other.
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Re: Difference between 0.5W and 3W

Post by Road_Hog » 01 Apr 2015, 14:01

I always hear this dilemma, and the unequivocal answer is along the lines of power doesn't matter, it won't make much difference.

Let me put this statement juxtaposition.

Your wife/girlfriend/shag says that size doesn't matter.

Two of the above statements are outright lies.

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Re: Difference between 0.5W and 3W

Post by Sofar » 01 Apr 2015, 14:41

Powermax wrote:I have a couple of TTI 1446 PMR radios which apparently are able to be modified to 3W by a 'simple' soldering procedure.

However, it doesn't look simple to me as the circuit board is tiny of course and one slip of the hand with the iron could ruin it.

So the question I am asking is, would it be worth the risk? How much difference will I see if I jump to 3W?

a) in a standard built up area
b) on top of a hill with a view of 50 miles

I already have a 'better' antenna - a Nayogi 771, which is noticeably better on TX than the pen spring which is shipped with the set.
As far as the power difference, from my tests on 2 meter simplex. With 2 watts I was giving the receiving station a full scale signal, with 0.5, he could still hear me but it was noisy, sometimes the extra wattage simply helps to "fill in", and overcomes the ambient noise.

70cm/440 has a lower noise floor, but there is more path loss. So, switching down to 0.5 from 2 watts, the receiving station could still hear me fine, despite no signal on the S meter, but if any noise/interference came up, it would cover up the audio.

As far as the PMR/FRS radio the non-detachable is the weakest link, and it seems to be an intentional design feature, the sensitivity of the receiving stations transceiver/antenna dictates whether you will be heard.
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Re: Difference between 0.5W and 3W

Post by Road_Hog » 01 Apr 2015, 15:37

Sofar wrote: As far as the PMR/FRS radio the non-detachable is the weakest link, and it seems to be an intentional design feature,.
Er...yes. To conform to the 0.5w ERF power output. Because it's ERP, not just 500 miliwatt, it has to be a measured output.

Edit: Oops, just noticed it is a non-UK poster, so not au fait with UK regs, my apologies.

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Re: Difference between 0.5W and 3W

Post by Powermax » 01 Apr 2015, 16:56

Thanks for the replies guys. I've always known that antenna is THE most important factor (from my CB days) but I had heard differing opinions of the use of extra power on 446.

I have another question which is about antennas. I'm using a Nagoya 771 (also have a 701). Both of them outperform the stock antenna on Tx, HOWEVER they do not receive any better. In fact I suspect the 771 maybe a tad worse then the stock on Rx, which just seems bizarre.

This leads me to thinking that I may have counterfeit antennas (there are lots around so I hear) which have poor SWR, only if that was true then the Tx performance would be poor too?

Do any of you guys find that your 'better' antennas don't improve much, if at all on Rx?

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Re: Difference between 0.5W and 3W

Post by Road_Hog » 01 Apr 2015, 17:37

Powermax wrote: This leads me to thinking that I may have counterfeit antennas (there are lots around so I hear) which have poor SWR, only if that was true then the Tx performance would be poor too?

Do any of you guys find that your 'better' antennas don't improve much, if at all on Rx?
Yes, you probably have fake aerials.

No, mine TX & RX better.

I have a genuine REUEX Nagoya NA-771 which cost me a tenner and a genuine Diamond RH771 which cost me a score.

Neither came from ebay or AliExpress/409Shop, both from reliable suppliers, with a fair amount of research done beforehand, to ensure I was getting the product I paid for.

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Re: Difference between 0.5W and 3W

Post by Powermax » 01 Apr 2015, 18:12

Thanks Roadhog.

Care to divulge this trusty supplier? :)

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Re: Difference between 0.5W and 3W

Post by RogerD » 01 Apr 2015, 20:04

If we call it a 4x power boost, the extra power will make you 6dB (a S point) stronger on any given path. If a path is noisy but just readable on the lower power, the extra power will help. That's all we can say - range is a tricky thing.

With two-way radio it's Sod's Law that you always seem to be on the limit of readability, so extra power is worth having so long as your battery lasts as long as you need it to.

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Re: Difference between 0.5W and 3W

Post by Road_Hog » 01 Apr 2015, 20:24

Powermax wrote:Thanks Roadhog.

Care to divulge this trusty supplier? :)
The NA-771 came from Knights of all places. I'm not sure if he still does them, but he had the genuine stuff for a while. I wouldn't buy it without seeing a photo of it to confirm it's kosher.

Radioworld supplied the RH771, Dave was quite upset when I emailed to ask if he had genuine ones and knew his supplier.

Something about, how dare you insinuate that I sell hooky gear.

http://www.buytwowayradios.com/blog/201 ... ennas.aspx

The Diamond just beats the Nagoya, but not by much. The Nagoya has the SMA connection, but the Diamond is BNC, so you need the adapter, preferably one of those that fits snugly, not one that looks like a tree hanging out of the top, with acres of space between the top of the radio and the centre of the adapter.

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Re: Difference between 0.5W and 3W

Post by 2E1IIP » 01 Apr 2015, 20:58

Powermax wrote:Difference between 0.5W and 3W
2.5W

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Re: Difference between 0.5W and 3W

Post by BK » 01 Apr 2015, 22:19

I think all the salient points have already been covered, but to summarise;

In free space (line of sight) you would get about double the range (range increases as the square root of power)
In an urban environment the increase in range would likely be negligible (diffraction loss is much higher)
Whatever signal the other station receives from you would be about one S point higher, which is a useful improvement on a weak signal
Any improvement will only be one way unless the other station increases their power too
Your batteries will run down much faster, and running the radio hotter could potentially shorten its lifespan

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Re: Difference between 0.5W and 3W

Post by Road_Hog » 01 Apr 2015, 22:40

BK wrote:In an urban environment the increase in range would likely be negligible (diffraction loss is much higher)
Absolute piffle. Go to London, stand a mile away, and tell me you won't hear much difference between 500 mw and 3w.

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Re: Difference between 0.5W and 3W

Post by MC68k » 02 Apr 2015, 05:27

Not sure about range, it depends on many conditions as mentioned above, but for sure battery will discharged faster.
Thru-hole is good, SMD is good as well, but boring.

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