At 11:06 AM 4/14/2011, radio...@frontiernet.net wrote:
Hello all, Can anyone tell me if the RX2 IN on the 5000A gets shorted out during transmit? It will be connected to an all band vertical 70' away from the main tower with dipoles and beams on it for 80m to 6m. I plan to receiver in diversity so the RX2 IN will probably have large voltages on it being so close to the main antennas on the tower. I don't want to burn up the 2nd receivers input circuit as you might expect.... So, does the 5000a protect this input during transmit or should I be shorting out or disconnecting that input?? Dennis KÃEOO
Don't know about shorting the input, but it may not be necessary - back in July 2009, Gerald gave us some specs to work with as far as tolerable input RF levels to the receivers are concerned:
At 06:30 PM 7/14/2009, Gerald Youngblood wrote:
I found where I sent it off reflector. Here is what I said about the FLEX-5000: The receiver input has ESD protection diodes that clamp at 3.3Vpp, which is +13.6 dBm. I have run +20 dBm into the receiver on many occasions in the lab without damage. The receiver ADC will overload at about 0 dBm with the preamp off and -14 dBm with the preamp on. Separation between the transmit and receive antennas is a good idea. There are a number of people running FDX with the second receiver without incident. Generally, I would stay below 0 dBm to keep a safety margin. Gerald Youngblood, K5SDR President FlexRadio Systems
For those wanting to know the voltages associated with the dBm levels Gerald quoted, there is a calculator at http://www.analog.com/Analog_Root/static/techSupport/designTools/interactiveTools/dbconvert/dbconvert.html
Tim, could you put this stuff in to the KB? Jerry W4UK _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
