John As you may be aware the values are dependent on resin-content and conditions. I attach values measured in standard lab conditions: Regards.....JIm Francey AlliedSignal Laminate Systems (also [log in to unmask]) FR4 (DISSIPATION FACTOR) 57%RC 1.3GHz 0.023 3.6GHz 0.023 5.6GHz 0.020 35% RC 1.2GHz 0.016 3.4GHz 0.018 5.4GHz 0.014 *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************