FlexRadio Systems FLEX-6000 Signature Series User Manual

FLEX-6000 Signature Series - SmartSDR for Windows Software User’s Guide
Page 146
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34.5 FULL DUPLEX ANTENNA ISOLATION REQUIREMENTS
For successful FDX operation, it is essential to understand and plan for sufficient transmit to receive
antenna isolation to prevent receiver overload and/or damage. The FLEX-6000 FDX Power
Calculation Worksheet can aid in the calculation of antenna isolation and power levels that are
suitable for a specific station.
The FLEX-6000 Signature Series transceivers are designed to disconnect the receiver from the
antenna when signal levels are +18 dBm to +22 dBm depending on frequency. The front-end
protection circuits will begin to engage at approximately +15 dBm. Front-end overload of the SCU
will occur with a single tone in the range of +8 dBm with the preamp off. Increasing the preamp gain
will lower the overload point by the amount of the added gain.
To provide suitable headroom to prevent SCU overload, we recommend that transmit to received
signal strength be limited to a worst case of -20 dBm or lower at the antenna input. With 20 dB of
preamp gain, this would provide a single tone input of 0 dBm to the A/D converter leaving about 8
dB of headroom. More isolation is better.
One of the best resources for information on achieving antenna isolation is:
"Managing Interstation Interference, Revised Second Edition" by George Cutsogeorge, W2VJN.

FlexRadio Systems FLEX-6000 Signature Series Specifications

General

Brand	FlexRadio Systems
Model	FLEX-6000 Signature Series
Category	Transceiver
Language	English