At 09:13 PM 2/11/06, Laryn K8TVZ wrote: > > > I guess I'll modify the challenge. Drop the 200 watt transmitter by 6 dB > > and see if it gets noticed. Bench tests are a good yardstick. Real world > > applications can be different. > > > > Chuck > > WB2EDV > >We could all probably save a lot of money by using RG142 or RG214 >going up the tower. Why does anyone use Heliax anyway?? Just a >thought... > >Chuck, I suspect that many users may not notice a 6db drop. But some >will. It'll depend on where they operate within the coverage area.
Very true. Many years ago a local machine had the PA die. The owner pulled the PA deck and brought it down off of the hill. This was on Santiago Peak (pronounced San-tee-ahh-go, for the non-california members) at about 5,000 feet. As an afterthought, and only because it was simple to do, he patched the Mastr II exciter to the duplexer... instead of 90w to the duplexer it was under 1w. It was absolutely amazing just how much coverage the system had considering the loss of the isolator, pass cavity, duplexer and feedline. >And just because some don't, doesn't mean that I will not be on a >constant mission to make and keep any repeater that I take care >of the best, RF-wise, that I can. This discussion brings to mind the points made on the web page at <http://www.repeater-builder.com/antenna/3db.html>... and they apply to 6db as well as to 3db... "The quieting curve of an FM receiver is very non-linear. 3 dB will make a very noticeable difference if the signal is well into the noise, barely any or none at all if it's strong. The result is that a 3 db improvement will in most cases approximately double your range." "A 3 dB change in power is not noticeable or barely noticeable _if the signal is already well out of the noise_. However, in areas where you are trying to push repeater coverage from a given site to the limits, 3 dB is significant on the outer fringes and in the problem areas. I say this from personal experience; I have seen a 3 dB change in repeater power or antenna gain make a significant and consistent improvement in fringe/weak areas. It can be enough to make the difference between the repeater being usable or not... I call that significant." Mike WA6ILQ 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/
