> 1. Many SO-239s provided as part of radio equipment are not up to the > quality of Amphenol units. In particular, the spring fingers of the socket > for the male pin loosen over time to the point that the connection becomes > less than solid. This is particularly a problem if the connector is used > repeatedly. I usually replace with Amphenol units...
I have nothing against the SO-239s used in the K3, although during assembly, I decided to use Amphenol connectors as a substitute. I also like using Amphenol-branded SO-239s on custom projects. The added expense for the name is usually a small percentage of the total project cost. > 2. The other potential problem with UHF connectors, in my opinion, is the > integrity of the shield connectivity through the connected pair. If the > backshell loosens, there is no longer a solid connection either at the > toothed parallel portion, nor through the backshell. And that's my objection to the UHF connector combination. For example, I gained 0.75 dB in the shack on 10m simply by re-tightening a series of connectors that seemed hand-tight. After installing some new equipment, I decided to conduct a loss budget analysis from the transceivers to the shack antenna output ports and all points in between. I was seeing too much loss through the system. When I used slip-joint pliers and ensured that the teeth of all '259s mated with the '239s, measured shack losses were minimized. I have a lot of switching here and with switching, there are many UHF connectors. Electrically, the sole conduction mechanism of the PL-259 is the inner surface of the threaded shell and to Joel's point, the threaded shell is only press-fitted against the connector body. A low-loss connection path is wholly dependant on the force of the shell to the body and the shell against the 239 threads. It's a miracle the UHF connector works at all. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
