[Elecraft] loss of RX sensitivity

Wed Sep 19 10:24:57 EDT 2018

As I remember, the bnc and n actually plug together. What then is the benefit of n? Water resistance?

Chuck Jack 
KE9UW

Sent from my iPhone, cjack 

> On Sep 19, 2018, at 7:28 AM, Dave B via Elecraft <elecraft at mailman.qth.net> wrote:
> 
> Hi Jim.
> 
> Mostly, N connectors, BNC's, TNC's, SC and 7-16's.  And for the big
> stuff, EIA flange connectors.  Plus some other weird stuff.  (3 lug
> BNC's and such, to prevent the "wrong connection".)    The odd
> appearance of the C connector on some US kit too.   Some "Spinner" 'BN'
> series connectors to, also often seen in the European Broadcast industry
> and some military.
> 
> A lot of US equipment also still use the various unique to the US
> connectors, often seen on big Bird loads etc.  Not so common over hear.
> 
> That based on what I've seen on kit "being tested" at customers sites
> over the last 28 years.
> 
> The only UHF series connector commercially used, that I've personally
> seen in that time frame is on a very old design of screened room weld
> crack detector, and it's a nightmare to use as it's always working loose.
> 
> To Charlie.
> 
> The threads have no part to play in the RF path on a UHF connector, it's
> all down to the two outer mating faces being pressed together.  The
> older (so called) MIL spec types, that had all the castelations at that
> point were *MUCH* better because of it, as they sort of interlocked and
> made a much better contact due to the metal to metal force
> multiplication that results..   They also tended not to rotate relative
> to each other so the retaining ring stayed tight.  Basic mechanical
> design feature, missing on the modern versions, where the two parts can
> rotate, even when the ring is (allegedly) tight.
> 
> The modern stuff with the 4 slots on the socket, and two bumps on the
> plug, are just utter crap.  (Built down to a cost.)
> 
> I'm amazed that no maker has innovated gone back to the original design,
> and fitted a crinkle spring washer behind the locking ring, so that
> contact pressure can be maintained, and also helping to keep the threads
> from working loose when subject to vibration...
> 
> But even then, they'd still only be of any practical use below 100MHz
> due to the impedance mismatch issue.   (Originally for use below 30MHz.)
> 
> https://en.wikipedia.org/wiki/UHF_connector
> 
> Stick with BNC's, N's and if you have too, 7-16's.  They are all easy to
> fit to cable with practice, no special tools needed unless you insist on
> the crimp types, and then you *MUST* have the correct tooling for that
> particular make of connector.
> 
> The pressure gland fitting types, are also easy to remove, clean up and
> re-fit if a cable becomes damaged.
> 
> All it takes is some practice.  Buy some surplus ex-military patch
> leads, and practice removing and refitting them.  After a few of each it
> becomes very easy.
> 
> 73.
> 
>    Dave G0WBX.
> 
> 
>> On 19/09/18 12:15, Jim Miller wrote:
>> Hi Dave
>> 
>> What does NATO use in place of pl259?
>> 
>> Thanks!
>> 
>> Jim ab3cv 
>> 
>> On Sep 19, 2018, at 4:16 AM, Dave B via Elecraft <elecraft at mailman.qth.net> wrote:
>> 
>> Wunder, I'll second you on that!
>> 
>> Of all the 1000's of RF connectors I've assembled and used over the
>> years for my own hobby and at work.  The venerable "UHF" series have
>> always proved to be the nastiest most unreliable types ever.  Period.
>> 
>> All my own personal radio kit, either get's them replaced (Sadly, not
>> always an easy job) with a N or BNC (in one case, a TNC.)  Or a BNC (or
>> N) adapter is securely fitted as a permanent fixture (including LocTite
>> on the threads, in mobile/portable situations!)
>> 
>> I also use BNC's at HF, as we do at work.   They can happily carry well
>> over 150W at up to 220MHz even in the presence of some very bad VSWR's
>> (6:1 or higher.)  Assemble them correctly and look after them
>> physically, and they will last a lifetime.
>> 
>> The UHF series are just plain unreliable.  It is no surprise that the
>> military (NATO) don't use them any more.
>> 
>> 73.
>> 
>> Dave G0WBX (also G8KBV)
>> 
>> 
>> ------------------------------------------------------------------------
>>> On 18/09/18 19:45, elecraft-request at mailman.qth.net wrote:
>>> Message: 1
>>> Date: Mon, 17 Sep 2018 16:45:10 -0700
>>> From: Walter Underwood <wunder at wunderwood.org>
>>> To: "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>
>>> Subject: Re: [Elecraft] loss of RX sensitivity
>>> Message-ID: <CEF1DF11-28D1-4409-8023-4C4CA0C81B4A at wunderwood.org>
>>> Content-Type: text/plain;    charset=utf-8
>>> 
>>> The next time someone challenges me on why I only use BNC and Type N connectors, I?m going to send them this entire discussion.
>>> 
>>> wunder
>>> K6WRU
>>> Walter Underwood
>>> CM87wj
>>> http://observer.wunderwood.org/ (my blog)
> 
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