Sharing an antenna between Rx and Tx RF modules ?

Started by Simon Clubley in comp.arch.embedded10 years ago 8 replies

I'm currently doing some experiments with 433MHz license free RF modules. Is it practical to share one antenna between a Tx and Rx module in...

I'm currently doing some experiments with 433MHz license free RF modules. Is it practical to share one antenna between a Tx and Rx module in a half-duplex environment, and if so, what techniques are used ? I would need a microcontroller to be able to switch the antenna between the Tx and Rx modules as required. I know that the proper solution would be to use a transceiver with Tx and Rx...


Free antenna simulation software?

Started by larwe in comp.arch.embedded7 years ago 2 replies

This is actually for a school project... so warning in advance! I would like to simulate an antenna design - exactly one. A very simple...

This is actually for a school project... so warning in advance! I would like to simulate an antenna design - exactly one. A very simple antenna; it's supposed to be a receiver for UHF digital TV signals. What I'd ideally like is a 3D estimated plot of the pattern after drawing in the basic geometry. I could build one and scope it out with a sig gen and a spectrum analyzer, but this will inv...


How to improve SNR in Antenna Cirsuit Design

Started by Johnson Liuis in comp.arch.embedded13 years ago 8 replies

I am looking into an existing GPS mini-size patch antenna design (1575MHz), which includes an LC low-pass filter, an amplifier with RFI...

I am looking into an existing GPS mini-size patch antenna design (1575MHz), which includes an LC low-pass filter, an amplifier with RFI suppression (BFP640), and a pi attenuator about 3 dB. The SNR values are generally 5dB lower than normal. So I am wondering if I remove the pi attenuator, will the SNR be able to get improved? I also found the antenna ground was not big enough (about 26mm...


RF Switcher and Current Monitor Sample

Started by Johnson Liuis in comp.arch.embedded12 years ago 6 replies

Hi there, I am currently working on a GPS Receiver that is able to support both internal and external antenna. I would like the system to...

Hi there, I am currently working on a GPS Receiver that is able to support both internal and external antenna. I would like the system to detect the external antenna and switch to the external antenna automatically. I remembered I once read a sampe from a magazine that required a RF switcher and a Current Shunt Monitor (like INA138) to detect the current, but I forgoty where it was. C...


Safety barrier for RFID antenna?

Started by ElderUberGeek in comp.arch.embedded11 years ago 14 replies

I am planning to use a RFID antenna (reader) in a Zone 0 explosive classified area, and it is connected to an apparatus which is located in a...

I am planning to use a RFID antenna (reader) in a Zone 0 explosive classified area, and it is connected to an apparatus which is located in a non-classified zone. My question is, what type of circuit do I need to build inside my equipment (i.e. not a separate unit) in order to make it intrinsically safe? I know it has something to do with zeners but I would appreciate some guidance and exampl...


MIMO and AAS

Started by karthikbalaguru in comp.arch.embedded10 years ago 3 replies

Hi, What is the difference between multiple input multiple output (MIMO) system and Adaptive antenna system (AAS) ? I find the WiMAX uses...

Hi, What is the difference between multiple input multiple output (MIMO) system and Adaptive antenna system (AAS) ? I find the WiMAX uses MIMO and AAS . But, the definition appears to be the same. Both the systems are exploiting more than one antenna to improve the coverage and the system capacity. I wonder why different naming convention for the same system !! :(:( Is there any ...


50 ohm PCB antenna track impedance

Started by comp.zrch.embedded in comp.arch.embedded8 years ago 2 replies

I am designing a PCB which will use a GPRS modem. The connection between the Antenna SMA connector and the GSM modem is via a 20mm 50 ohm PCB...

I am designing a PCB which will use a GPRS modem. The connection between the Antenna SMA connector and the GSM modem is via a 20mm 50 ohm PCB track. This is a two layer 1.6mm thick 1 oz copper PCB and the 50 ohms impedance is achieved with a 260 thou track in a ground plane with 8 thou clearance over a solid ground plane,. Do I really need to get the PCB impedance checked by the pcb manufactu...


DIY indoor TV antenna cost less than 10 cents

Started by Anonymous in comp.arch.embedded3 years ago

http://bbs.creaders.net/upfile/image/20140905/20140905163018_45450_big.png it is good for channel 4.1 ~ 51.2

http://bbs.creaders.net/upfile/image/20140905/20140905163018_45450_big.png it is good for channel 4.1 ~ 51.2


Microwave communications

Started by Anonymous in comp.arch.embedded9 years ago 7 replies

I need to design a system that communicates in the microwave range (> 5GHz) using a horn antenna... Does any body know if there are any off the...

I need to design a system that communicates in the microwave range (> 5GHz) using a horn antenna... Does any body know if there are any off the shelf chipsets, or can point me in the direction of any reference designs or manufacturers. The system would be very low power. Cheers Ross


GPS receiver question

Started by vorange in comp.arch.embedded9 years ago 6 replies

I'm looking for an easy to use/integrate gps receiver. I've come across tyco's products. Is one of these babies all I would need or is there...

I'm looking for an easy to use/integrate gps receiver. I've come across tyco's products. Is one of these babies all I would need or is there some 'antenna' or other stuff required that's not shown in the picture? I plan to hook it up to an MCU. http://www.tycoelectronics.com/gps/modules.asp If there's anything better you've come across, please let it be known. Thank you.


3V <-> 5V Level shifter ?

Started by Martial Chateauvieux in comp.arch.embedded13 years ago 15 replies

Hi, I want to connect a GPS Smart antenna SAM LS from u-blox, to the UART of an atmega128 running under 5V. ...

Hi, I want to connect a GPS Smart antenna SAM LS from u-blox, to the UART of an atmega128 running under 5V. Unfortunately the GPS runs in 3V and has 3V compatible IOs. I set up a 3V regulator already for the power supply. Can someone explain how to build a level shifter from 3V to 5V with a transistor ? (How do I choose it, how to...


Adding GPS receiver to an Embedded System

Started by Anonymous in comp.arch.embedded13 years ago 4 replies

Theres several low power GPS receivers out there (ex. Trimble's Lassen iQ), but aside from the hardwre interfacing to it what else...

Theres several low power GPS receivers out there (ex. Trimble's Lassen iQ), but aside from the hardwre interfacing to it what else is required? Ive never used or owned anything with GPS, just figured it would be a neat project, but is gps data free, just hook up an antenna and go? Or does it require some kind of existing account for authentication?


GPS time module

Started by Michael Schuster in comp.arch.embedded10 years ago 3 replies

Hi, I'm searching for a gps time module (giving time to my embedded hardware). Can you gice me some recommendations? Antenna must be...

Hi, I'm searching for a gps time module (giving time to my embedded hardware). Can you gice me some recommendations? Antenna must be seperately. Michael -- Remove the sport from my address to obtain email www.enertex.de - Innovative Systeml?sungen der Energie- und Elektrotechnik


Naive wireless question

Started by Don Y in comp.arch.embedded6 years ago 9 replies

Hi, Is there any difference (hardware-wise) in the "radios" (chipsets) on the AP end of a 802.11b/g/n link and those on the "client"...

Hi, Is there any difference (hardware-wise) in the "radios" (chipsets) on the AP end of a 802.11b/g/n link and those on the "client" end? I.e., is the difference merely one of antenna gain, Tx power and *firmware* (meaning software that conceivably *could* be rewritten vs. software that is deeply and immutably buried within the chipsets)? Said yet another way, could 'n' PC's with wire...


Siemens TC35iT technical datasheet

Started by Ross Marchant in comp.arch.embedded12 years ago 1 reply

If anyone has this datasheet please email it to me. :) Siemens requires registration through a reseller to access the technical documents. I...

If anyone has this datasheet please email it to me. :) Siemens requires registration through a reseller to access the technical documents. I need it to confirm that the unit will work in our setup. Alternately if anyone could tell me how to power the damn thing... There is only an antenna connection, RS232 port, one 4-wire and one 6-wire phone sockets. Thanks Ross


PIC 18f with RFID! communication problem!

Started by ishka in comp.arch.embedded2 years ago 1 reply

Hi, I am trying to interface RFID(RFid click which uses CR95HF 13.56 MHz contactless transceiver as well as trace antenna) with PIC18F8722. It...

Hi, I am trying to interface RFID(RFid click which uses CR95HF 13.56 MHz contactless transceiver as well as trace antenna) with PIC18F8722. It used SPI communication. I am trying to get its eco-response but there is no output! I checked using oscilloscope the spi_write operation which is perfectly fine but i guess the problems is in read operation. i am attaching my code. Any help would be appre...


low cost Bluetooth interface?

Started by Roland Zitzke in comp.arch.embedded12 years ago 4 replies

Hi, I am searching for a module which provides an encapsulated bluetooth interface - the connection doesn't really matter but a serial...

Hi, I am searching for a module which provides an encapsulated bluetooth interface - the connection doesn't really matter but a serial interface would be fine. The goal is not to have to mess with bluetooth certification, stack development, antenna issues etc. It will be a low bandwidth application, no audio or anything that requires high data rates. I'm talking higher quantities (seve...


Want a chip to block AC contamination

Started by Johnson Liuis in comp.arch.embedded13 years ago 7 replies

I am a newbee in RF circuit design. I found sometimes the small AC components from input antenna ( < 1.5 GHz) can contaminate the DC Power...

I am a newbee in RF circuit design. I found sometimes the small AC components from input antenna ( < 1.5 GHz) can contaminate the DC Power supply (Vcc) without a proper protection. Vcc is used to feed the first stage amplifer. Of course I can use a traditional LC networks to block the AC components from Vcc. However, I hope somebody can recommend me a small IC chip which can do the same


Development of a cheap wireless sensor node

Started by arslan in comp.arch.embedded10 years ago 6 replies

I want to develop a cheap wireless sensor node with short range (500ft). I am a novice in the field of wireless, therfore i dont want to work...

I want to develop a cheap wireless sensor node with short range (500ft). I am a novice in the field of wireless, therfore i dont want to work on designing an antenna. I am looking for small and cheap full/half duplex modules with low datarate to attach to my digital circuit. Are any such modules available


Need sources for pot with planetary drive

Started by msg in comp.arch.embedded10 years ago 14 replies

Greetings: Please view these photos of a three-turn planetary drive pot that uses a conventional "stackpot" formfactor...

Greetings: Please view these photos of a three-turn planetary drive pot that uses a conventional "stackpot" formfactor at http://www.cybertheque.org/homebrew/rcvr/images/antennas/pot.jpg Resistance = 1K It was made in 1966 by CTS; stampings: 36129 137.6637 Does anyone recognize this pot technology? Any suppliers nowadays? I need the form factor for modifications to antenna rotator as...