Recent content by dervast

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?

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...

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...

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...

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...

I would like to thank you for your reply. Best Regards Alex

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

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?

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/...

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

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...

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...

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...

any kind of help please?

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...