My CommShop software calculates that an isolation of 78 dB is needed for no desense. Bear in mind that this software makes a number of assumptions in computing isolation values, so don't treat the answers as absolute. Tube-type PAs can get by with much less isolation, due to the lower noise levels when compared to solid-state PAs. There are significant differences between receivers, even between models made by the same company.
More info about the CommShop software can be found here: http://www.dcico.com/dcilmr.htm 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Eric Harrison Sent: Wednesday, September 03, 2008 9:05 PM To: [email protected] Subject: [Repeater-Builder] Re: 6 meter Repeater Ok Great this helps. Any idea the db of isolation say for 50 watts and .35uv 12db sinad @ 1.7 mhz split? Eric N7JYS -- In [email protected] <mailto:Repeater-Builder%40yahoogroups.com> , "Eric Lemmon" <[EMAIL PROTECTED]> wrote: > > Eric, > > Your question cannot be answered properly unless you provide the power > output of your transmitter and the 12 dB SINAD sensitivity of your receiver. > Therefore, I will offer some calculations based on some assumed values: > > 25 watt transmitter, 0.35 uV receiver, 1.7 MHz split: 237 feet vertical > separation, 13,368 feet horizontal. > 50 watt transmitter, 0.35 uV receiver, 1.7 MHz split: 282 feet vertical > separation, 18,905 feet horizontal. > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> > [mailto:[email protected] <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of Eric Harrison > Sent: Wednesday, September 03, 2008 7:18 PM > To: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> > Subject: [Repeater-Builder] 6 meter Repeater > > Well regardless if whether 1.7MHz split in the 6 meter band is or is not > a national US band plan split, it is an accepted split by the Kansas > State Repeater Cordinator as my repeater is cordinated on 52.850/51.150 > by them and has been for over 2 years. Just getting it back on the air > at a new site. Wasn't trying a war here just trying to get some answers > on the dB isolation needed and acceptable vertical antenna separation > needed for a 1.7MHz split on 6 meters, which is my reason for posting > but have failed to see anyone give the answers I needed. > > Eric > N7JYS >
