Hi Eric, > "Eric Lemmon" <[EMAIL PROTECTED]> wrote: > Skipp, > It is not just a cautious road to travel; it may also be an > unnecessary one. Since repeater coverage is primarily limited > by its ability to receive the low-powered distant stations, 250 > watts of transmit power may be far in excess of what is needed > for a balanced system.
Two things quickly come to mind. First you assume a "balanced system" is the best operation, which not everyone including myself agree with 100%. Second is how everyone assumes the repeater system must be designed for low powered distant stations, which again is not always the best or most desired option. > Even at sites where the noise floor is very low, that much power > hardly seems necessary. Each case is different... there is a great case to honk the serious power if it can be done well. Many owners don't do high power repeater operation very well and I suspect the reason has to do with the corresponding non-linear increase in technical & hardware requirements. > Ironically, an increase to 250 watts from, say, 100 watts may > result in reduced receive sensitivity if the duplexer must be > improved to handle the higher power without desense. The power > increase may allow the repeater to be heard full-quieting at a > greater distance, perhaps a 20% increase, but may also reduce > the ability of distant stations to be heard full-quieting by > the repeater. In other words, an increase in power might result > in a reduction in the coverage area. Sure if the system is not properly designed and installed. But higher power operation well done is a beautiful thang... > I'm not just making this stuff up- I have seen it happen more > than once. At one Ham repeater site, the previous owner of a > repeater had a TE Systems power amplifier set for about 150 > watts hooked up to a Wacom 4-cavity duplexer. Even though the > duplexer was perfectly tuned, it just couldn't handle that power > level without some desense, and the coverage area was relatively > small. When I took out the TE amplifier and fed the 15 watt > driver directly to the duplexer, the coverage area ballooned > to at least five times its previous distance. Some of the Hams > who now were able to use the repeater from a considerable distance > asked, "Wow! What did you do-triple the power output?" They > were floored when I responded, "No, I cut it by a factor of ten!" Simple, the previous owner tried to plug and play his repeater equipment without doing the proper homework. Just think how well the system would have worked with 150 watts and the proper duplexer or combiner system in place. > I make no claim that my experience is typical, but I do assert > that "More is not always better." YMMV... > 73, Eric Lemmon WB6FLY Please see my previous post where the "no free lunch" rule is mentioned. There are numerous well done high power 2M repeaters in operation in our area of the State and they are obviously very well thought out systems. Having a very high-level flamethrower repeater around is not only a great communications resource... if the hardware operates well it's also impressive on your technical resume and a lot of fun to operate. cheers, s.
