Hello, Matt and Welcome to MyGMRS. Glad that you registered and please feel free to post any questions that you may have about equipment, procedures and protocols... we have a very intelligent membership here at the forum and everyone is eager to assist others.
A couple of things to remember, the biggest attenuator to FM communications is the ground. Path loss on a 50W GMRS radio, a commercial grade receiver, and 1/4 wave antennas is nearly 6000 miles. However, this number goes south quickly when you start talking about punching through urban environments, trees, hills, etc. With GMRS, you're pretty much guaranteed a successful transmission if there is unobstructed line of sight. More power means greater risk for desensing the receiver (what good does it do to have a repeater that can be heard for 100 miles but only talked to for 35?) which means adding extra filters, more antenna separation, etc.
The 675 and 700 repeaters in Lubbock. The 675 repeater is on the tallest building for 120 miles. The antenna is 360 feet off the ground. It's running 50W at the transmitter and 40W at the antenna (which is a DB420).That's 477W ERP. It fizzles out about mile marker 41 on I27 (it's located at marker 4 roughly). The 700 repeater is a good 70 feet below it running 32W (23W at the DB420)...it fizzles out around mile marker 38. The two sites are 1000 feet away from one another. 70 feet is what mainly makes up that extra 3 miles.
95% of the time, you'll never notice the difference between a repeater running 200W or one running 25W if it's in a good location.
MSensei reacted to PastorGary in The required "new guy" Hellos!!
