Nate Duehr wrote: [snip] > Never seen a combiner system made with isolators and mixers have a TX > cavity beyond it on the antenna side... but I guess it could be done? > > Of course, usually the systems feeding such a combiner have TX cavities > on them of some sort... not always, though. > > But... I'm just an Amateur. And I haven't seen much of anything. I > know there's pros on this list. (Speak up, pros.) Just following in > much larger footprints. >
Nate, What you are using is a hybrid-ferrite combiner. By design they exhibit a 3dB loss per mix point. In addition to their inherent high loss, the other negative is they do expose the world to the non-linearities of the isolators. The one positive is there is no minimum frequency separation between connected transmitters. A much lower loss combiner uses cavities and isolators. They exhibit typically <2dB instead of 6dB for four (or many more) TXs with wide spaced transmitters and as the transmit spacing decreases, the insertion loss goes up. Below is an example link: http://www.sinctech.com/catalog/product.aspx?id=750 The upside is much lower loss and the world is protected from the non-linearities within the isolators. The downside is more cost and depending on the design / cavity Q, the minimum frequency spacing on high band is 60 KHz or more. I don't know of any of the more crowded sites in southern California that would accept a hybrid-ferrite combiner due to possible interference to others co-located / nearby systems. Ed Yoho WA6RQD 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/
