Tony: Doubling your XMTR power will only get you a 3 dB increase in output power. That's about 1/2 a unit on a receiver's S meter. Is that worth the expense?
73, Dick W1NMZ ----- Original Message ----- From: Tony L. To: [email protected] Sent: 05 February, 2007 06:47 Subject: [Repeater-Builder] Effects of doubling RF output on UHF repeater? One of our 70cm Amateur Radio repeaters is currently outputting 50 watts into the duplexer. We're considering replacing the existing RF power amp with a 100 watt model. Current draw on the 50 watt unit is 8 amps. The 100 watt unit will draw 20 amps. Our power supply is rated at 36 amps continuous, and the duplexer is rated at 250 watts. Half of our users believe that the repeater's output power is perfectly matched to its receiver. That is, users of high powered mobile radios generally lose repeater reception at about the same time the repeater's receiver loses them. However, the other half of our users believe doubling the repeater's power output would generate increased activity since the repeater could be heard more "comfortably." We could upgrade without changing any of our other infrastructure. However, these questions arise: 1) Will the hundreds we pay to upgrade actually translate into significantly increased range? 2) Will we risk generating additional receiver noise by doubling our output power, thus losing coverage in the process? 3) Will using a higher power level shorten the life of other system components over time (e.g., power supply)? By the way, our frequency coordination would be valid even if we doubled our output power.
