Thanks Don; I remember that we went over this earlier in the thread. Highly unlikely that I had legacy stuff as I became a ham in 2015 and acquired most of my stuff new.
I am inclined to think that it was more possibly an out of spec 50 ohm connector or a manufacturing defect. I've already worked on the finger bending thing but I ageee that given my lack of success that I'd be best served by spending the $47 and just buying a new assembly and replacing it. I appreciate all the help and suggestions from all the Elecraft community. On Fri, Mar 9, 2018 at 17:48 Don Wilhelm <[email protected]> wrote: > Rich, > > Since you have traced the problem to the contact between the female BNC > and the male (yes your twisting and applying pressure confirms that is > the problem). > > It is entirely possible that if you had some old cables made with old 75 > ohm BNC male connectors, that they could have enlarged the female pin > causing it to become marginal when used with the 50 ohm male connectors. > > You may have success with a very slender tool to bend the 'fingers' of > the female connector toward the center, but the best cure is to replace > that connector. > > Before we get into another long discussion of 50 ohm and 75 ohm center > pin diameters, let me say that modern BNCs use the same diameter center > pin for both. > That was not always true, so beware when buying older BNC jumpers at > hamfest flea markets - the old ones could be old 75 ohm BNCs with the > larger center pin. Those less than 10 or 15 years old are OK. > It may also be that *some* imported BNC connectors do not have the > proper diameter. For best results, buy only Amphenol connectors or > other trusted brands. > > 73, > Don W3FPR > > On 3/9/2018 11:13 AM, rich hurd WC3T wrote: > > I've pretty much exhausted most of the permutations of my cables and > > connectors. The only persistent behavior is that if I apply slight > > pressure to the side of the BNC connector where it plugs into the jack on > > the KX3, or sometimes if I twist it and then apply slight pressure just > so, > > I see a jump in the noise floor and instead of the internal ATU wearing > > itself out and giving up with a 9:1 or 7:1 SWR, it immediately tunes to > 1.0 > > or 1.1. I have removed/swapped all my the antenna leads. I have four > of > > them, all Cables On Demand (Amphenol) manufacture. I also have a number > of > > BNC to banana plug jacks, and even an MFJ-1899T. If I replace the leads > > without doing the twisting-and-slight-pressure thing, I lose the RF > > connection; the S meter has no indications on it, and the noise floor is > > nonexistent. > > > -- 72, Rich Hurd / WC3T / DMR: 3142737 PA Army MARS, Northampton County RACES, EPA-ARRL Public Information Officer for Scouting Latitude: 40.761621 Longitude: -75.288988 (40°45.68' N 75°17.33' W) Grid: *FN20is* ______________________________________________________________ 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 Message delivered to [email protected]
