Re: [Repeater-Builder] Connector plating vs PIM etc.
Jeff DePolo wrote: Now, having said all of that, my real-world experience with single-frequency-pair repeaters (not combiners or other multicarrier systems) is that I've never had a PIM problem that I could attribute to connector plating. Any connector that I install is silver-plated (or H+S Succoplate), but I don't go to the trouble/expense of replacing non-silver-plated connectors on equipment like duplexers, radios, etc.. Jeff, Thanks for all the info and the links for further reading! I appreciate the wealth of information. I had a very busy weekend and am still digesting some of the info, but I will come away with a much better understanding of the subject. The bottom line for me is probably this is something I don't need to worry about. It is a low RF site and I have just one transmitter. Paul N1BUG
Re: [Repeater-Builder] Connector plating vs PIM etc.
John J. Riddell wrote: Paul, there is a product made here in Canada by DW Electro chemicals called Stabilant 22 that works wonders on connectors. It is a liquid and is about 35 dollars for a very small bottle. You just put a very small amount of it on each mating surface of the connectors and it becomes highly conductive between the two metal surfaces. I used it on all of my repeater antenna connections and had excellent results in lowering noise problems. Interesting! I've heard of that stuff and probably need to get some and try it on the pins of the audio processor board on my Mastr II PLL exciter. Every once in a while the audio goes away, but pulling that module and re-inserting it fixes it every time. I'm staring to believe the noise problems I've been fighting for years were just band antennas... an old fiberglass collinear that had gone bad, and a new Sinclair dipole array that apparently had issues from day one. Everything is running *perfect* with the single dipole I threw up on the tower. Paul N1BUG
Re: [Repeater-Builder] Connector plating vs PIM etc.
Paul, there is a product made here in Canada by DW Electro chemicals called Stabilant 22 that works wonders on connectors. It is a liquid and is about 35 dollars for a very small bottle. You just put a very small amount of it on each mating surface of the connectors and it becomes highly conductive between the two metal surfaces. I used it on all of my repeater antenna connections and had excellent results in lowering noise problems. John VE3AMZ - Original Message - From: Paul Kelley N1BUG paul.kelley.n1...@gmail.com To: Repeater-Builder@yahoogroups.com Sent: Friday, May 22, 2009 7:16 AM Subject: [Repeater-Builder] Connector plating vs PIM etc. OK, I guess it's about time I asked this. Is there someplace I can find a reference on various connector types (plated or not, type of plating) vs PIM/IMD/noise in duplex systems and/or in high RF environments? I am looking at replacing my run of LDF5-50A and wonder what type of connectors I *should* use. I always *thought* silver plated connectors were the way to go. But it is obvious none of the connectors on my DB4062B duplexer are silver plated. They are silver in color but they do not tarnish at all after many years... clearly not silver. I've also noticed on this Sinclair dipole array that I had problems with, the 3 x N(f) tees are silver plated but the mating N(m) connectors on the harness are not. Brass, silver, gold, tri-metal (?)... help! What are the accepted rules for connector choice for duplex systems and/or in high RF environments, and why? What about mating connectors with different plating? If a repeater is in a very low RF environment, does it even matter? Thanks! Paul N1BUG Yahoo! Groups Links
RE: [Repeater-Builder] Connector plating vs PIM etc.
OK, I guess it's about time I asked this. Is there someplace I can find a reference on various connector types (plated or not, type of plating) vs PIM/IMD/noise in duplex systems and/or in high RF environments? I am looking at replacing my run of LDF5-50A and wonder what type of connectors I *should* use. Nickel-plated connectors, which are the most common type, are generally to be avoided. As I recall, nickel-plated connectors typically test 20 to 40 dB worse in two-tone PIM tests than silver plated. Gold over nickel is also not good (a lot of cheap hamfest connectors/adapters that are gold plated inside and out tend to be regular nickel/brass connectors with a thin gold plating). Gold-plated *center pins* are generally acceptable for small connectors (BNC, N, SMA, etc.). Connectors with larger center pins (EIA flange, 7/16 DIN, etc.) usually are silver-plated. Silver plating is better from a PIM and conductivity standpoint, but gold doesn't tarnish, hence the tradeoff. There are also some considerations regarding soldering to gold - it can partially dissolve in the molten solder resulting in the solder becoming more brittle. Huber+Suhner and others have other special platings that are low-PIM yet don't tarnish like silver (Sucoplate and Sucopro). Regular nickel-plated brass connectors are still an acceptable choice for test cables and other uses where they will see repeated connection/disconnection because the plating doesn't scratch, oxidize, or deteriorate as quickly do some of the other types, but for a repeater installation, stay away from nickel. http://www.ieee.li/pdf/essay/passive_imd.pdf http://www.imscs.com/passive-intermodulation.html http://www.tessco.com/yts/customerservice/techsupport/whitepapers/passive_in termod.html http://www.hubersuhner.ca/co-ca-us/hs-p-rf-con-kb-plat.pdf I don't pretend to be a metallurgist - somebody else may have better/additional information. This is just what I've heard/learned over the years through my own reading. As far as connectors on your LDF5, I still like the old-style connectors with the thread-in center pin (L5PNF would be N female, silver plated). They simply don't fail, unlike some of the newer connectors (RingFlare, OnePiece, etc.) which I have had problems with occasionally, especially on larger cable. Now, having said all of that, my real-world experience with single-frequency-pair repeaters (not combiners or other multicarrier systems) is that I've never had a PIM problem that I could attribute to connector plating. Any connector that I install is silver-plated (or H+S Succoplate), but I don't go to the trouble/expense of replacing non-silver-plated connectors on equipment like duplexers, radios, etc.. --- Jeff WN3A
