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young
Joined: 24 Jun 2004
Posts: 285
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| will high power increase wireless communication capability? |
 Posted: Mon Mar 07, 2005 5:44 pm |
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| I am using TWS434 and RWS434 and I am currently providing +5V power supply. The datasheet said that it could accept 2-12VDC. I wonder if the higher the power supply the longer transmittance distance? THANK YOU |
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Guest
Guest
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| Power increase |
| Posted: Mon Mar 07, 2005 11:24 pm |
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Young -
I briefly played with these units a long time ago and I was under the impression the output (transmission) power was fixed, although the supply voltage could vary as you note. I would be suprised if the supply voltage could be used to crank up the transmisssion power, and hence the transmission distance. I'll check into it.....
Bill |
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Guest
Guest
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| Power output |
| Posted: Mon Mar 07, 2005 11:33 pm |
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Young -
I was wrong! The rf power output when 9 V < Vcc < 12 V is 16 dBm, and when 5 V < Vcc < 6 V the power is 14 dBm.
Check it out:
http://oap.sourceforge.net/datasheets/rf.pdf
Bill |
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Imanjl
Joined: 15 Nov 2004
Posts: 42
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| Posted: Tue Mar 08, 2005 12:41 am |
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I had the same problem and then use some kinds of RF MOSFET Amplifier Module from mitsubishi (RA07H4047M) ,that give us 7W POWER in output with input about 20Mw...
The output power of TWS-434 is 8mW but it still working and increase the transmission distance greatly ....
Im still a little doubtful about conflicting these two ,,cause i had some problems to run it,,,,,
if anyone has a suggestion about these inform me,,,,,, |
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jds-pic
Joined: 17 Sep 2003
Posts: 205
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| Posted: Tue Mar 08, 2005 12:22 pm |
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| Imanjl wrote: | | I had the same problem and then use some kinds of RF MOSFET Amplifier Module from mitsubishi (RA07H4047M) ,that give us 7W POWER in output with input about 20Mw... |
you are emitting 7W ERP in the ISM band?
you are located in what country?
jds-pic |
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Imanjl
Joined: 15 Nov 2004
Posts: 42
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| Posted: Tue Mar 08, 2005 1:41 pm |
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| Quote: | you are located in what country?
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I do it just for test ,,I know the max Power in my country is 10 MW and for accesing more power we must have somthing like a license ... |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Tue Mar 08, 2005 2:09 pm |
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| where you find TWS output is 8mw, I checked the datasheet, the output is 14-16dbm which equal to 25-40mw, use the amplifier you mentioned will be 7w. |
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Imanjl
Joined: 15 Nov 2004
Posts: 42
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jds-pic
Joined: 17 Sep 2003
Posts: 205
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| Posted: Tue Mar 08, 2005 4:48 pm |
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| Imanjl wrote: | | 14-16dB but datasheet says that RF max power is 8mv ,I Dont know how u calculate it |
dBm = dB referenced to a milliwatt
for power calculations, every 3dB increase doubles the power.
0 dBm = 1 milliwatt
3 dBm = 2 milliwatts (~)
10 dBm = 10 milliwatts
13 dBm = 20 milliwatts (~)
20 dBm = 100 milliwatts
30 dBm = 1 watt (1000 milliwatts)
33 dBm = 2 watts (~)
36 dBm = 4 watts (~)
note, you should observe as well that
-10dBm = .1 milliwatts (100uW)
-20dBm = .01 milliwatts (10uW)
and so on
for exact calculations you'll need to learn the formula for converting dBm to watts, and vice versa. you'll need to brush up on your logarithmic math. here is a great website for finding this info:
http://64.233.161.104/
ps:
similarly, dBuV = dB referenced to a microvolt, etc.
pps:
if you are having trouble with distance i suggest you use a better antenna, rather than increasing the finals output. with 7W into a dipole or 1/4 lambda groundplane antenna, your signal can be heard 25 or more miles away. this is totally unnecessary, and in most cases illegal -- you could end up interfering with medical or public safety services.
(73 de)
jds-pic |
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