This sounds wild. However, if he's running 1300' of 0.750 CATV trunk line, his loss could be as much as 2.0 dB per 100-foot. That's 26-dB loss. Take out say 6-db for antenna gain. This leaves him with 3-Watts ERP. If it was 1.0 dB per 100-foot, then the ERP would be about 60-Watts. I just hope he has remote receivers in various and diverse locations around the periphery of the transmitter site for maximum system effectiveness.
Steve ----- Original Message ----- From: "kf0m" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, November 03, 2004 10:50 PM Subject: RE: [Repeater-Builder] Solid State VHF PAs (200+ watts of power) > > Here is the situation with the repeater I maintain that runs 300W on TX. > Repeater antennas are at 1300 ft feed through 3/4 in 75 ohm line. The > majority of the user base is 40 to 60 miles from the site. We have a remote > input about 60 miles from the repeater to provide HT and mobile coverage > for where the majority of the users are. With all the feedline loss and the > distance from the users, we need the 300W Tx power to provide good coverage > where the users are. > > The repeater is also the primary skywarn repeater with wide area coverage of > the state and users need to be able to hear the repeater well in adverse > weather conditions. > > With 300W, I can hear the repeater from my house which is 50 miles from the > repeater and I can get into it on the HT with the rubber duck using 200 mw > through the remote receiver. With the repeater running 100W for TX, I can > get into the repeater using the HT but can't hear it on the rubber duck. > > John Lock KF0M > Wichita KS > kf0m at arrl dot net > > > -----Original Message----- > > From: Kevin Custer [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, November 03, 2004 8:09 AM > > To: [email protected] > > Subject: Re: [Repeater-Builder] Solid State VHF PAs (200+ watts of > > power) > > > > > > > > RE: Excessive power. > > > > Neil McKie wrote: > > > > >I can only wonder why the need for what seems to me is excessive power? > > > > > > > Most folks will agree that a repeater that is working properly (no > > desense) having a receiver sensitivity of .35 uV (- 116 dBm) for 12 dB > > SINAD, and a transmitter power of 110 watts will likely be fairly well > > matched in receive/transmit coverage considering a modern 50 watt mobile > > rig. > > > > Now, lets add a receiver preamp on the repeater and increase its > > sensitivity by say 6 dB to -122 dBm. Considering the repeater still > > operates properly, without desense, this same repeater would now require > > 480 watts of transmitter power to be matched as above. > > > > That being said, 200 + watts of transmitter power doesn't seem to be > > excessive to me, but it depends on what is there to hear the user. > > > > Kevin Custer > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
