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Recent content by gkuma

  1. gkuma

    RF Circuit Book

    Thanks for that I actually have that book but haven't looked into it. I will now. Do you also have a suggestion about fm, am modulation, psk, fsk, qi? Thanks
  2. gkuma

    RF Circuit Book

    HI I am just getting into circuit design and signal processing. I was hoping to find a book that includes RF circuit design and things like transient analysis, quench pulses. Does anyone know of a good book to read?
  3. gkuma

    VHF Outdoor Testing

    I wouldn't have nearly enough absorber. Anywhere to purchase for cheap? Last time I checked it was fairly expensive. My current setup I am just using a signal generator and function generator to do my measurements. This way I have the cables come down vertically like you mentioned and don't...
  4. gkuma

    VHF Outdoor Testing

    Yes I see your point. 6ft high was kinda my worry, I think I should go higher. I measured two dipoles, one TX and one RX and with my setup got -7.8dBm received power. Using the Friss equation I should get around -8.5 if both were 2.11dBi. Is there anyway to calculate a good test setup, ie...
  5. gkuma

    VHF Outdoor Testing

    Hi I have some testing of an antenna in the VHF range and would like some suggestions on how to properly measure the gain. The setup I have currently is transmitting a 180MHz signal with unknown gain of the antenna being received by a dipole with assumed gain of 2.11dBi(Probably closer to 2)...
  6. gkuma

    Diversity Antenna

    What about a LTE-MIMO application? I understand the diversity antenna is similar to the primary maybe not having as much bandwidth in the bands or efficiency. But looking at a gain standpoint(S21), should the diversity antenna be within 2dB of the primary antenna at least at some point in...
  7. gkuma

    Diversity Antenna

    Anyone know where I can find requirements for a diversity antenna for a cell phone? Like how many dB should the LB and HB differ from the primary antenna? Is there a set of rules for this?
  8. gkuma

    Dual band microstrip feedline.

    Hey I have a question about designing a feedline for a dual band antenna. I have a 2.4, 5.8GHz antenna attached to a ground plane and was wondering how you guys would design a 50ohm feedline. I did it the way I was taught but am getting varied differences between simulation and tests...
  9. gkuma

    Axial ratio

    Well I guess I am just doing a relative measurement between the antenna I am replacing and mine. Currently I need 6dB and my antenna simulates very close. So can I use a home made dipole and achieve sufficient data to determine where my antenna is?
  10. gkuma

    Axial ratio

    Ya I found the emco 3121 kit thats used for $1500 but I wont ever go lower than 400MHz. I will actually be doing the test outdoors first and then in an anechoic chamber. The application is for an antenna communicating with a sattelite and gps system. It needs to be completely accurate. I...
  11. gkuma

    Axial ratio

    I was thinking of using something like this: http://www.tessco.com/products/displayProductInfo.do?sku=85825&eventPage=1 Would that work? I searched EMI stuff and they are around $300. I am measuring the axial ratio for a circularly polarized antenna. Is it the same way for a cross...
  12. gkuma

    Axial ratio

    Hi, Does anyone know where I can find a dipole antenna in the range of 400MHz? I plan on using this as a reference antenna to measure the axial ratio of a CP antenna. Can anyone help me on a good way to do this? Also if a different reference antenna I should be using. Thanks!
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