Kirti Barpande wrote: >Hello! Experts, >I want to transmit a 500 MHz sinusoidal signal, 2 to 3 volts peak to peak >over 300 metres long coaxial cable. Can it be successfully done with minimum >loss using coaxial cable? Which cable will be more suitable? I Plan to use >RG-8 cable. >Kirti > > > > RG-8 (Belden 9913) has a loss of 3.02 dB/100 feet at 500 MHz RG-8 (Belden 8237) has a loss of 4.8 dB/100 feet at 500 MHz For a matched cable 300 meters long you will have the following losses: Belden 9913: -29.75 dB or a voltage ratio of .0316 Belden 8237: - 47.27 dB or a voltage ratio of .0043 Since dB=20log (V1/V2) So your output voltage will be about (3*.0316) 0.048 volts for 9913 cable or (3*.0043) 0.0129 volts for 8237 cable. Exotic rigid heliax like Andrew LDF6-50A would give you about 9.57 dB loss or abour .94 volts at the end of your cable (at a cost of many $$$$/meter) Bottom line: 500 MHz over 300 meters of coax can't be done with low loss! (at least with commonly available cables) Ray Anderson WB6TPU Staff SI Engineer Sun Microsystems ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu