[Elecraft] [KX3] BNC connector oddity on KX3

Ronnie Hull w5sum at comcast.net
Wed Feb 21 16:19:30 EST 2018 

Ditto Frank
I work in the communications industry and he BNC ODDITY BUG has bitten my butt more than once!!

Ronnie W5SUM

Sent from my iPhone

> On Feb 21, 2018, at 3:14 PM, donovanf at starpower.net wrote:
> 
> If only Dale's comment were true... 
> 
> 
> As far as I know all 75 ohm BNC connectors made in the USA use 
> the correct diameter center pin. 
> 
> 
> However... 
> 
> 
> This is NOT true for many import connectors and adapters, even 
> modern high bandwidth 75 ohm import connectors often have serious 
> design and quality control problems. I've found three categories of 
> serious reliability problems with import 75 ohm BNC connectors 
> and adapters. 
> 
> 
> - much smaller center pin diameter, they're copies of 40 year old 
> obsolete "made in USA" 75 ohm BNC connectors 
> 
> 
> - center pin slightly too small in diameter -- a quality control or 
> manufacturing problem that causes unreliable connections. 
> 
> 
> - tapered center pin with incorrect diameter over most of its length 
> that causes unreliable connections 
> 
> 
> Don't believe me? I have modern import connectors with all three 
> types of problems. 
> 
> 
> 73 
> Frank 
> W3LPL 
> 
> 
> 
> 
> 
> ----- Original Message -----
> 
> From: "Chris Cox, N0UK" <chrisc at chris.org> 
> To: "Dale Parfitt" <parinc1 at frontier.com> 
> Cc: "Chris Cox, N0UK" <ygsoftrock40 at chris.org>, kx3 at yahoogroups.com, elecraft at mailman.qth.net 
> Sent: Wednesday, February 21, 2018 4:25:15 PM 
> Subject: Re: [Elecraft] [KX3] BNC connector oddity on KX3 
> 
> Indeed - i didn't know that. Thanks for the info, Dale. 
> 
> SO, if you have an OLD 75 Ohm BNC plug... :-) 
> -- 
> 73 Chris Cox, N0UK, G4JEC 
> chrisc at chris.org 
> 
>> On Mon, 19 Feb 2018, Dale Parfitt wrote: 
>> 
>> The center pin on 50 Ohm and 75 Ohm BNC’s has been identical for perhaps 20 
>> years. The 75 Ohm impedance is now attained through modification of the 
>> connector’s dielectric structure. 
>> 
>> 
>> 
>> Regards, 
>> 
>> 
>> 
>> Dale W4OP 
>> 
>> 
>> 
>> From: KX3 at yahoogroups.com [mailto:KX3 at yahoogroups.com] On Behalf Of 'Chris 
>> Cox, N0UK' ygsoftrock40 at chris.org [KX3] 
>> Sent: Monday, February 19, 2018 12:29 PM 
>> To: rich hurd WC3T 
>> Cc: kx3 at yahoogroups.com; elecraft at mailman.qth.net 
>> Subject: Re: [KX3] BNC connector oddity on KX3 
>> 
>> 
>> 
>> 
>> 
>> Not saying this IS the problem but i fth emale BNC plug is a 75 ohm 
>> connector, its centre pin will be a narrower diameter and may only be 
>> making intermittent contact with the female socket on the KX3. 
>> 
>> -- 
>> 73 Chris Cox, N0UK, G4JEC 
>> chrisc at chris.org 
>> 
>>> On Mon, 19 Feb 2018, rich hurd WC3T rich at wc3t.us [KX3] wrote: 
>>> 
>>> Hi, 
>>> 
>>> I had an oddity with hooking an antenna to the BNC connector on my KX3 
>> that 
>>> happened enough times to be chalked up to something other than random 
>>> chance. Looking for opinions on whether my solution aligned to your 
>>> experience(s). 
>>> 
>>> I have a complete station - a KX3, a PX3, and a KXPA100. The KXPA100 is 
>>> connected via a Cables On Demand connector with a PL259 on one end and a 
>>> BNC connector on the other end. All other interface cables are Elecraft 
>>> standard. 
>>> 
>>> This is NOT the first BNC connector that I've used. Prior to this last 
>>> acquisition I had a couple of other BNC to PL259 jumpers that I was using, 
>>> and the usual smattering of connectors and adapters in the junque box. 
>>> 
>>> No matter which one I used, If I removed the BNC connector from the rig 
>>> (maybe to go portable, for example, or the last time it was because I 
>>> installed Eneloop Pro batteries to the internal battery holders) I would 
>>> put everything back together, and then would have severe - almost 
>>> debilitating - signal attenuation when I got the rig fired up. If I 
>>> twisted and spun the BNC connector on the jack, it would improve, and then 
>>> get bad again more often than not. It could take up to 20 minutes to get 
>>> everything "dialed in" so that the signal was appearing again. God help me 
>>> if I accidentally moved something after that. And of course, while all 
>>> this was happening the ATU was having fits, with 99:1 SWR readings and the 
>>> amp was going offline; all kinds of weirdnesses. After things calmed 
>>> down. the ATU behaved itself, the amp stopped being pouty, and all was 
>> then 
>>> good. 
>>> 
>>> Thankfully, now that I have the Cables On Demand product, things seem to 
>>> have quieted down - although I still don't disconnect without provocation. 
>>> :) Though I'm desperately afraid of when I start to go mobile after the 
>>> snow melts and the weather gets nice again. :) Hope I can get my IC706 
>>> fixed and back in service as my base station before that occurs. 
>>> 
>>> My question was going to be in desperation more than anything else if this 
>>> last cable didn't work, but thankfully, that's been the only cable vendor 
>>> that I trust for any of my specialized cables and they haven't failed me 
>>> even with this one. 
>>> 
>>> Are BNC connectors that finicky? Is it possible that I just had a bad 
>>> batch of low quality jumpers? I'm just wondering if anyone else has had 
>>> excessive fiddling with their BNC connections. 
>>> 
>>> --- 
>>> 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* 
>>> 
>> 
>> __._,_.___ 
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