10dbm distance

Hi,

Can anybody tell me the reliable function range of such combination of TX/RX:
TX: +10dBm RF module in ASK/FSK mode on 433MHz
RX: -105dBm sensitivity RF receiver
I mean the open-area range. The TX and RX are hybrid modules from Telecontrolla.
Anybody knows about other alternatives in such modules (manufacturer) in similar prices ?


Thanks in advance.
Bogusz.

You can see Melexis's TH7122 and TH71221.

den

You have to use free-space calculation formula to determine the max range.

The general formula for pathloss is:

L= 32.4 + 30log(f) +20 log(d)

where d is distance in kilometers and
f is frequency in megaherz

You shift the formula to get distance as a function of pathloss.

Your pathloss will be the difference between TX and RX powerlevels.

You should also take into account directivity of your antenna. In case you will be using vertical dipole, then the gains is 2.5 dB.

If you expect to have somekind of reflections, you should also calculate fading margin and substract that from your max possible pathloss.

in incorrect

Correction: L= 32.4 + 20log(f) +20 log(d)

Using the formula:

-105 = 10 -32.4 - 20log(f) - 20log(d) =
= 32.4 + 20log(433) + 20log(d)

--> 20log(d) = 10 + 105 - 32.4 - 20log(433)
= 29.87 dB

---> d = 10^(29.87/20) = 31.15 Km

Answer: dmax = 31.15 Km

31.15 Km, huh? Glad you can be so precise! But send us some of what you are smoking!

From my experience, you should expect 30 to 150 meters range, depending on the various parameters/data rates you set up.

>But send us some of what you are smoking!

No need to be rude. Jallem gave a correct and plausable value for the free space range. 30KM hilltop to hilltop with 10mW is no great feat. A fraction of a watt from
a LEO satellite 400 miles up is easily receivable on a low gain antenna.
It just goes to show that in practise losses due to obstructions and areas of peaks and null's due to multipath reception are what sets the range.
Not to mention the background noise from electrical equipment in urban areas.

The drogaddict here is you...!...What arrogant you are....ignorant..
Maybe you need to go back to school....maybe better need to get school
to learn.....

Added after 9 minutes:

An antenna radiates ....how can this be explained physic
You are just a ignorant arrogant.....arrogant ignorant?

All right, all right... let's calm down... :)
Thanks a lot for everybody that answers me!
I think both answers (30-150m & 30km) were right... depending on the transmition medium (true deep free space) and normal earth atmosphere with imminent noise sources...

Greetz.

>depending on the transmition medium (true deep free space) and
>normal earth atmosphere with imminent noise sources...

It's the solid objects such as people, walls, buildings and the earth itself rarther than the atmosphere. Google for fresnel effect. eg at 433MHz on a 1Km link you need the mid point of your link to be 7meter above the ground to avoid the fresnel effect.