J
JustinDePolis2
Guest
Here's an interesting post for those of you that could offer any advice. I am developing a wireless video system that operates on 1.2Ghz. The transmitter is surface mount, and has an output of approximately 250mw. The receiver is at a fixed location. The pair comes with small antennas. The idea here is to get more range, so I have come up with a couple ideas. First off, the receiver is located in a vehicle, so of course, an external 1.2Ghz antenna would be required. Then I have a few ideas on how to increase the receiver sensitivity.
The idea that I forst had was a broadband 1.2Ghz amplifier with about 10db or so of gain, I was concidering one of the typical radio shack "cable" amplifiers that would go up to about 1.2Gig, and test it's gain up there. Then I started thinking... DirecTV operates at about 1.27Ghz or so, and they have inline amplifiers available designed for long cable runs, and to compensate for "rain fade" a condition when there is an overcast, the signal level goes a bit low.
The amplifier, well let's back up a bit. The LNB on the dish is powered by the receiver through the coax cable with either 11 or 13 volts present, which the receiver alternates as it tells the LNB which transponder to use. (even or odd, as there are 32 transponders on the 101 degree satellite, which is directv)
So, my idea here is to use the amplifier which I think they state has 20 DB of gain, and will work fine at 1.2Ghz, and power it from 13.8 volts. This is where I have to get creative. Due to the nature of the DTV system, *NORMALLY* the amplifier would pass the DC through the amplifier, the amplifier using what it needs, and then passing it to the LNB on the dish. I don't care about DC being present on the antenna, although I would prefer it not be. I however, DO NOT want DC going into the 1.2Ghz wireless receiver. This would be a bad thing. So... I need to isolate the DC from the antenna, and the receiver, while providing a low-loss path for the RF at 1.2Ghz. Normally, the answer would be simple, use a .01 capacitor, and it would work just fine. But, for 1.2Ghz, I need a low loss way to do this... any ideas?
Click Here To Go To FG Best Communications
</p>
The idea that I forst had was a broadband 1.2Ghz amplifier with about 10db or so of gain, I was concidering one of the typical radio shack "cable" amplifiers that would go up to about 1.2Gig, and test it's gain up there. Then I started thinking... DirecTV operates at about 1.27Ghz or so, and they have inline amplifiers available designed for long cable runs, and to compensate for "rain fade" a condition when there is an overcast, the signal level goes a bit low.
The amplifier, well let's back up a bit. The LNB on the dish is powered by the receiver through the coax cable with either 11 or 13 volts present, which the receiver alternates as it tells the LNB which transponder to use. (even or odd, as there are 32 transponders on the 101 degree satellite, which is directv)
So, my idea here is to use the amplifier which I think they state has 20 DB of gain, and will work fine at 1.2Ghz, and power it from 13.8 volts. This is where I have to get creative. Due to the nature of the DTV system, *NORMALLY* the amplifier would pass the DC through the amplifier, the amplifier using what it needs, and then passing it to the LNB on the dish. I don't care about DC being present on the antenna, although I would prefer it not be. I however, DO NOT want DC going into the 1.2Ghz wireless receiver. This would be a bad thing. So... I need to isolate the DC from the antenna, and the receiver, while providing a low-loss path for the RF at 1.2Ghz. Normally, the answer would be simple, use a .01 capacitor, and it would work just fine. But, for 1.2Ghz, I need a low loss way to do this... any ideas?
Click Here To Go To FG Best Communications
