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Take a look at the amplifiers from RFMD. Their PA product page is at
https://www.rfmd.com/productView.asp?iCombination=2&iApplication=0&iStandard=0&iProductFamily=1
Re: Variable gain amplifier
Hi Cyberblak,
Glad to help. Other companies making VGA chips would be Linear Tech and National but I think you'll find them around the same price range. On the prices of Analog Device parts; they have a fairlywide selection. Some are real specialized, like very low...
Re: Variable gain amplifier
You can just connect the gain control voltage lines from both the amplifiers together and feed the same control voltage into both. Make sure that the second amplifiers input will not be overloaded by the first amplifiers output. The voltage gain slope will be twice...
Re: Variable gain amplifier
Take a look at the VGAs from Analog Devices. No one amplifier gives you 60db of gain but you could put two in series. Link for these is at:
**broken link removed**
One problem with FR4 is the variation in its dielectric constant from batch to batch. It can vary by at least +/- 0.5. Maybe your antenna design can take this variation. A quick simulation check using the extreme values for the dielectric constant will answer this. If this is acceptable then...
There is no easy way to do this. Ideally you would need a bi-directional amplifier coupled to your phone and of course this is not practical.
This next idea is maybe not practical either but....if you have access to some point in your building where you can get phone reception and your room is...
pi 4 qpsk
Hey,
QPSK modulation represents symbols by a constellation of four phase angles of an RF carrier. There are two bits per symbol. So for example 00 = 45 degrees, 01 = 135 degrees, 10 = 225 degrees and 11= 315 degrees. The phase is free to change from any position to any other position...
Re: Extend the power
There is really no easy way to do this and even if you do there are other considerations to take into account. You would have to open up the back of the radio and do some modifications. See where the telescopic antenna is soldered to the PCB. Unsolder it and replace it...
Re: Digital transmitter:
Hi,
This is a very open ended question. But what I would do is this. First get a book that goes into the basics of digital radio design. As a suggestion you could look at:
Transceiver and System Design for Digital Communications, 2nd edition
By: Scott R. Bullock
This...
Hi,
Take a look at MMANA. It is a free antenna program. There is a learning curve but there is a lot you can do with it. It is located at.
**broken link removed**
Re: RF Band
The radio frequency (RF)band is part of the electromagnetic (EM) spectrum. It is generally considered that EM radiation with a frequency between 3 khz to 300 ghz is in the RF band and various regulatory bodies around the world divide up this portion of the EM spectrum for various...
Hi, Microwave antennas come in all shape and sizes. From parabolic dishes several meters across to small chip antennas less then a centimeter squared. There is a good online introduction to this subject at https://www.qsl.net/n1bwt/contents.htm
Also take a look at some antenna manufacturers...
Re: 25km wireless
Hi,
I am thinking that you are looking at a paging system here. Is that right? What are you wanting to send over the wireless sytem? How will it be used? If it is paging then you have some advantages over using the ISM bands since paging uses lower frequecies for the RF...
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