Bob, Thanks for info and links:-) I see where you are coming from...... For me, repeaters are a new deal and I am as dumb as a box of rocks, on the subject......that's why I subscribed to the group. My first repeater project is a portable system, so I have to make it compact for commissioning in hard to access locations, read carry the system on motorcycle. The physical size of high spec filters are too large and prone to transport damage, for my concept. With my Hamtronics low current draw boards, mobile filters with pre-selector, small battery & solar panel, 7m squid pole and 4dB antenna with accessories all fit easily on my off road motorcycle, which allow me to reach some good potential sites not accessible by 4x4, if needed.
73, Jack. VK4JRC Sent from my Apple iPad Tablet PC On Aug 1, 2010, at 12:00 PM, n...@no6b.com wrote: > At 7/31/2010 07:04, you wrote: > > > I don't believe that. But if you want NEW coaxial resonator filters: > > http://anglelinear.com/filters/coax_filters.html' > > These are actually a bit smaller than your typical cavity resonator, & > they're very low loss. Apparently Chip decided to tradeoff a bit of Q to > keep the loss low. But with 2 resonators you end up with a very low system > NF & selectivity only a bit less than the GLB (which is misleading, as I > explained in my previous post because some of that selectivity is after the > preamp, so it's still partially susceptible to OOB overload). > > If you factor in the ham discounts, the total for the dual coaxial > resonator/preamp combo is a bit more than the Simrex preselector. But we > KNOW the NF will be ~1.1 dB, we KNOW that ALL of the preselection will be > ahead of the preamp, so with that info we can properly design a RX system. > > The Simrex units are made in the US, so you still have to pay to have it > shipped down unduh. > > >IF the Simrex-GLB product did not perform..........the word would spread > >faster than the Black Plague and no one would buy them........ > > Not saying it doesn't work, but I am saying as an RF engineer that it's > impossible with the data in hand to properly apply it's use in a repeater > system. > > Bob NO6B > >
