jshank wrote: > Bruce, > > Do I need to spend the extra $ for LMR400 cable or could I just use > rg58 for a total run of 60 feet. > Jeff Jeff
A conservative approach would be to use a cable that has an attenuation of no more than 10dB (the attenuation of the cable supplied in the Trimble Thunderbolt starter kit). For standard RG58 this can mean no more than about 30ft. This only applies if the antenna preamp gain is similar to that of the Trimble bullet antenna. _Minimum Antenna gain for Thunderbolt_ http://trl.trimble.com/docushare/dsweb/Get/Document-30908/Product Bullentin 200213.pdf <http://trl.trimble.com/docushare/dsweb/Get/Document-30908/Product%20Bullentin%20200213.pdf> Above link specifies a minimum of 20dB gain at Thunderbolt input. Thus with 23 dBattenuation (cable plus active splitter) you would need to use an antenna with at least 43dB gain preferably a little more. With 10dB of cable attenuation and 3dB maximum splitter loss the antenna preamp gain should be at least 33dB. The 5V Bullet III antenna has 35dB gain and thus allows a maximum attenuation (cable plus splitter) of about 15dB, preferably a little less, when used with a Thunderbolt. GPS Timing antennas with higher gains (50dB) are available. Bruce _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.