1. B

    How to match ceramic antenna to GPS chip

    Hi, Current project is to move from a 1/4 wave whip antenna to a ceramic chip type (e.g. Johanson 1575AT43A0040). I have a pi matching network on the pcb and can look 'into' the antenna with my vector network analyser and get the conjugate impedance. I have tried to simply match that to 50...
  2. C

    Need help with FM Radio Transmitter / Amplifier

    So I purchased this : (HanRongDa HDR-831) HanRongDa HDR-831 It's working great but the practical range is about 15 meters. I'm looking to upgrade this. The thing is, I know very little about radio frequencies and antennas. Can something like this work ? Ebay Amplifier The device I purchased...
  3. BuyingOffDeath

    Unexplainable RF Power levels

    I have an RF Explorer to use to scan what RF's are around me. I am curious as I'm am just getting in learning about wireless transmission and propagation. However I can't explain these power levels of -10 dbm all the way to -0. The RF Explorer does seem to be working correctly just based off of...
  4. C

    Efficiency Finding and Parallel Connected Transistor

    Hello, I have two questions about this circuit. 1- What is the efficiency of the circuit and how to find it? 2- What is the purpose of connecting two transistors in parallel? Thank you for your time.
  5. E

    Designing PCB with multiple RF circuits

    I need Tips and recommendations on how to design a PCB with multiple RF circuits. In my case, the PCB includes a GPS receiver, 802.15.4 2.4GHz, and 433 MHz transceivers. I plan to use a GPS module with a patch antenna. The 433 MHz transceivers will have a PCB or ceramic antenna. an external...
  6. ashokraj

    Is there any technique in which I can send 433MHz and 915 MHz with the same antenna?

    Hi, I am using LORA. Is there any multiband antenna that can support these two frequencies? or I would need an antenna with the same footprint for 915MHz and 433MHz. Technically, as the frequency reduces antenna length increases. I am wondering with advancements in technology if at all...
  7. andkr

    Suggestions on choice of antenna in direction finding system using BLE

    Hello! I am currently doing a school project where we are going to design a direction finding system using antennas and an automated robot arm to adjust to angle. From what we have read the most reasonable choice of antenna is either a yagi or parabolic antenna. The robor arm is fairly small...
  8. okati

    Why can a radar with circularly polarized antenna not see a conductive surface?

    We know that conductive surfaces reflect the radar signals very well and the radar sees the surface. Why this is not like that when the antenna is circularly polarized?
  9. Microbe

    Trying to make a 50ohm 7Mhz antenna

    Hello. I have bought a ham radio kit. The instructions tell me to connect it to a 50ohm 7Mhz antenna. I've searched how to make one but there are only blurry schemes of antennas I can't understand. I would appreciate if someone that knew about this topic explained to me how to make one and...
  10. Answerz

    PsOC 4 BLE (pins problems)

    I am running a project using a thermistor. I started by using the evaluation board as shown: The program runs fine. After that, I removed the module from the evaluation board and powered the module using an external power source (3V). I moved the resistor and thermistor from the evaluation...
  11. Denis Molodtsov

    Can you spot a transmitter in this device? Can I add an antenna to this device?

    I have puchaed a wireless Bike Alarm and wanted to figure out how to extend its range. I want to try to extend its reach to 50 meters from the default 20 meters. There is wireless "fob" (KS-WL09C) that I disassembled. The photo is available below. Question: Can someone, please, spot a...
  12. N

    S-Parameters (Cascaded system) and a few questions on RF Design. (IIP3)

    Please see attached figure for a few of the questions. I would love for the solutions to these questions. Also, what are the effects when the width of the microstrip line is increased?
  13. N


    I have a 1.8 Ghz microstrip antenna. I need to turn this into an array microstrip antenna, but I can't. Can you help?
  14. AttacK

    LW/MW and FM antenna suggestion for old car radio (25 years old)

    First of all, i want to listen in my house, you can forget a car. It has been in the warehouse for a long time. Yesterday i tried it. Although I haven't connected an antenna yet, it still works. Because of it has 10-12 cm antenna plug cable probably. As it stands, FM is listened almost...
  15. genekuli

    If I hook up a HF ultra-wideband (UWB) amplifier with a transmitting UWB antenna (out) and a receiving UWB antenna (in)

    If I hook up a HF ultra-wideband (UWB) amplifier with a transmitting UWB antenna (out) and a receiving UWB antenna (in) and have the antennas very close (few inches) to each other inside a metal box (~40cm) so as to produce a feedback loop, then due to the noise and harmonics of the over-driven...
  16. A

    Antenna Radiation Patterns Explained

    Hi, Been struggling to find information that I find to be obviously missing on how to interpret antenna radiation patterns. For example have a look in the datasheet for my chip antenna. I can understand the three 2D radiation pattern graphs, one for each plane, what I don't understand is what...
  17. D

    Best way to orient antenna for strongest signal?

    I am planning on using the following radial choke antennas to try and trace an energized wire which travels along a wall. I'm having trouble figuring out the best way to orient this part to get the best signal. Any comments are much appreciated!
  18. Tibor10

    Balun and antenna for AX5243-1-TW30

    Hello everyone, could anyone help me how to find balun (one chip) for AX5243-1-TW30 868 MHz? And in addition could you recommend the most suitable antenna planar or chip? I understand that it depends on many factors but if you have any experience with configuration of AX5243-1-TW30 + balun +...
  19. V

    How to increase range of a BLE chip

    Hello I have an RN4871 Bluetooth chip and integrated it with my micro. The chip is scanning for nearby BLE devices and reporting them to the host micro via UART. However, I see that the range of this chip is just 10 m. I could buy RN4870 and increase the range to 50m, but that's still not...