BH1417F output power?

[things]

hey Guys, I have built a little kit called the "Micromitter". In the instructions, it says the BH1417F chip has a RF output of about 10W, but there is a few resistors on the board that are supposed to limit it to about 10µW. They say it can do about 20 metres, so I was wondering, what kinda distance could 10W do in a open area? I would like to extend the range a little, but I dont wanna be transmitting too far

EDIT: I just saw the datasheet of the chip, it says the transmitting current is 28ma ?

Cheers

 

[Nigel Goodwin]

hey Guys, I have built a little kit called the "Micromitter". In the instructions, it says the BH1417F chip has a RF output of about 10W, but there is a few resistors on the board that are supposed to limit it to about 10µW. They say it can do about 20 metres, so I was wondering, what kinda distance could 10W do in a open area? I would like to extend the range a little, but I dont wanna be transmitting too far

It's not 10W, or anywhere near that

You can extend the range slightly by removing the output attenuator, that's all you need to do.

 

[things]

Do you know what the output of the BH1417F is? It has a little GFWB3 filter on the RF output of the BH1417F, and that just then goes to a few resistors, then to the antenna. I am guessing i'd just solder the antenna to the direct output of the GFWB3?

Thanks

 

[Hero999]

10W is far too high for 28mA.

If the power output is to high then at an attenuator consisting of a couple of resistors.

For example the circuit attached cuts the power by 6dB (a quarter of the input power).

RL is the RF load, the aerial/antenna.
R2 is the same impedance as the load so the voltage across the load is halved giving ¼ of the input power.
R1 is an impedance matching resistor. To work properly transmitter requires a load impedance of 75Ω assuming the load is a ¼ wave monopole. RL and R2 in series have a total impedance of 150Ω so connecting a 150Ω resistor in parallel reduces the input impedace to 75Ω.

The power dissipation in the resistors is:
R1 ½ input power.
R2 ¼ input power.
The power dissipation relative to the input power is the same in this kind of attenuator regardless of the impedance or power rating.

 

[things]

Hi Hero, I am drawing up a diagram of my attenuator now, but do you know what kinda wattage the BH1417F can output by itself? Apparently it has a built in attenuator, and then a extra one on the circuit board. I am trying to get just abit more range, 20M is just abit dodgy. I just want to know wether the output power from this hting is gonna affect the whole neighborhood

 

[Nigel Goodwin]

Hi Hero, I am drawing up a diagram of my attenuator now, but do you know what kinda wattage the BH1417F can output by itself? Apparently it has a built in attenuator, and then a extra one on the circuit board. I am trying to get just abit more range, 20M is just abit dodgy. I just want to know wether the output power from this hting is gonna affect the whole neighborhood

Like I've already told you above, you get a slight range increase by removing the attenuator - it's not going to go very far.

 

[mvs sarma]

hey Guys, I have built a little kit called the "Micromitter". In the instructions, it says the BH1417F chip has a RF output of about 10W, but there is a few resistors on the board that are supposed to limit it to about 10µW. They say it can do about 20 metres, so I was wondering, what kinda distance could 10W do in a open area? I would like to extend the range a little, but I dont wanna be transmitting too far

EDIT: I just saw the datasheet of the chip, it says the transmitting current is 28ma ?

Cheers

while constructing the kit please do consider some interesting mods suggesticd with comments by one "AN920" at
https://www.electronics-lab.com/forum/index.php?topic=11519.msg62890#msg62890
it is posted on 9th june 2007