Aside from any possible receiver deficiencies, you might want to consider that the Vertex VXR7000 has a pretty weak PA section.
The earliest ones came thru with a discrete transistor PA. They became a problem like so many other PA's in that the collector current was too much for the pad & melted the solder & surface mount caps off. The next step was to add a rf module. This was ok but they didn't resurface the aluminum PA extrusion to accept the module directly. Instead, they created a new pcb & added a copper heat spreader plate as a retrofit to the existing aluminum heat sink. The problem there is the copper heat spreader doesn't have enough contact area to the aluminum heat sink to remove the heat from the heat spreader fast enough. I still use the VXR7000 in new installs but not in areas of high use. I still keep several of the retrofit kits & rf modules & install them as the old units die. Lastly, the internal duplexer, unless tuned with a return loss bridge, can present a poor swr to the PA module & pop it prematurely. I've run across a few that I tuned with a tracking generator & attenuators that looked good in all other respects but once the factory cables are attached, the output drops & the tuning goes off. You have to kinda' fudge the tuning once the factory cables are attached to get the power & isolation back. I also noticed the internal duplexer as sold with the unit (Sinclair) is very temperature sensitive. If I mistakenly hold my palm on the duplexer while tuning, that cavity will be tuned wrong once it cools down to room temp. The heat from the power supply & the PA will warm the chassis & the duplexer & throw the tuning off. If you can, use an external duplexer. It won't detune itself due to the heat buildup & offers better isolation/less loss. --- In Repeater-Builder@yahoogroups.com, Nate Duehr <[EMAIL PROTECTED]> wrote: > On Jun 2, 2007, at 12:35 PM, barrypal wrote: > > > Anyone running the Icom repeater in the ham bands? This question has probably come up before buy I couldn't find it. I am considering the Icom 4000 or Vertex 7000 for my ham repeater.
