Recent content by dervast

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    Measuring Co-Channel Interference: How Can It Be Done?

    and what if I have cochannel interference? For example in GSM networks due to the frequency reusability I might have some extra interference from an adjacent cell. I think in the C/I (SNR with no noise) tracks that. How I can find SNR or C/I in that case?
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    How Can I Determine Energy and Dimensions of a Signal with Perfect Antennas?

    Dear sophiecentaur I would like to thank you for your answer. I did the following assumption so to simplify things: I have a perfect omnidirectional antenna at H and E plane, for the transmitter. All the energy is equally distributed to everywhere For the reception antenna, let's assume...
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    Measuring Co-Channel Interference: How Can It Be Done?

    Hmm thanks for the replies ... In telecommunications we use a lot this SNR or C/I which means that I measure the received power source against the noise. In telecommunications this 'noise' is usually what comes from the outside 'world'. How I can define that noise 'in-real-time'? I would...
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    How Can I Determine Energy and Dimensions of a Signal with Perfect Antennas?

    Dear all, Let's assume that I have just bought the perfect omnidirectional antenna and I try to understand how the wavelengths are transmitted. If I got it right, there are wavelengths getting 'out' towards the 360 degrees directions. Now let's assume that I have a perfect receiver antenna...
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    Measuring Co-Channel Interference: How Can It Be Done?

    Dear all, I am trying to understand something for SNR, I know that is the ratio of the Power of a signal divided by the Power of noise. According to wikipedia Signal-to-noise ratio is defined as the power ratio between a signal (meaningful information) and the background noise...
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    Receiver antennas, performance metrics

    I would like to thank you for your reply. Best Regards Alex
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    Receiver antennas, performance metrics

    Can you explain that? Why it will give a poor antenna? In your last post you said that 1:1 is very good ratio.
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    Receiver antennas, performance metrics

    Thank you very much for your answer! The polar diagram for the reception how should be interpreted? I can see in the polar plor these 10,20,30db values. What do they really mean? +10,+20,+30 db in reception? Does this apply that the antennas has a gain in these directions?
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    Receiver antennas, performance metrics

    Ok I will try to make my questions more concrete by giving a real example. I have uploaded 3 pictures (I have hidden anything regarding model and brand) from the same antenna that is sold as receiver and transmitter antenna! First picture http://imageshack.us/photo/my-images/688/swrt.jpg/...
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    Receiver antennas, performance metrics

    If I understand it right the low SWR is the worst the performance is. I found a SWR diagram but instead of the double dot : (1:1) it only had a signle dot . (1.1) . I assume that they are the same equal. What would be good SWR values? Best Regards
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    Receiver antennas, performance metrics

    Dear vk6kro, I would like to thank you for your reply. I understand that an antenna that does 'everything' is hard to find! But still I want to be able to read the plots that come with antennas so get a first feeling how good or bad can it be (a first estimation). I have understood about the...
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    Receiver antennas, performance metrics

    Dear berkeman, I would like to thank you for your reply. I have found few antennas that can support wide frequency ranges from few khz to few Ghz. I have also in an spreadsheet file put the antennas with the prices, with the frequency ranges that support. Now I have also some how to qualify...
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    Receiver antennas, performance metrics

    Dear all, I am trying to understand what is the difference between a transmitter and receiver antenna. If I recall correctly an antenna is a dipole so you can always use it to either transmit or either receive. All the antennas that are used for transmitting purposes come with some...
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    How Do You Calculate Logarithms with Base 2 and Perform Decibel Calculations?

    logarithms and decibels please Hi i need some good tutorials for the logarithmsI(especialy for logarithms with base 2) and how i can calculate logarithms with base 2 when i have a simple calculator. Also i need some decibel tutorials that can help me understand how i can perform calculations...
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