Elecraft

loss of RX sensitivity

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riese-k3djc

Re: loss of RX sensitivity

https://www.eham.net/ehamforum/smf/index.php?topic=34680.0;wap2

Bob K3DJC

On Tue, 18 Sep 2018 16:53:01 -0400 (EDT) [hidden email] writes:

> Hi Wes,
>
>
> Thanks for forwarding the information about DG5MK's new FA-VA5
> VNA. What is its current selling price?
>
>
> If you use many BNC connectors, you'll notice a distinct difference
> in
> connector quality especially above 100 MHz. Avoid using BNC male
> connectors with weak tension when you turn the bayonette
> to engage the connector. If the bayonette turns too easily it
> doesn't
> maintain sufficient engagement force to keep the RF connections
> in proper alignment.
>
>
> 73
> Frank
> W3LPL
>
>
>
>
> ----- Original Message -----
>
> From: "Wes Stewart" <[hidden email]>
> To: [hidden email]
> Sent: Tuesday, September 18, 2018 5:51:45 PM
> Subject: Re: [Elecraft] loss of RX sensitivity
>
> It's difficult to argue with Frank's experience and expertise. That
> said, fools
> rush in...
>
> I own some network analyzers, 1) an N2PK which I built with type N
> connectors,
> 2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert
> AA-55 Zoom
> with a SO239. Professionally, I've used analyzers with type N, 3.5mm
> (beadless
> SMA) and K connectors. With the exception of the AA-55, which only
> goes to 55
> MHz, all of these can be calibrated with "precision" calibration
> kits that can
> cost thousands of dollars. So far, Frank is right, not a BNC in the
> bunch.
>
> But that has changed with the introduction of the DG5MK's FA-VA5,
> one-port
> vector analyzer. I am on the reserve list to buy one of these. The
> thing to
> note is that it is supplied with a BNC connector. There has been a
> lot of
> anguish, heartburn, etc about this on the VNWA Yahoo group but the
> consensus is
> that it will be fine and BNC calibration kit has been developed and
> tested
> without issue. https://www.youtube.com/watch?v=X8Z7veGV57o
>
> There are tens of thousands of BNCs on oscilloscopes and other
> instruments and
> I've seldom had an issue with them in 30+ years of lab work. For
> quick
> disconnect I also use short jumper cables with BNCs to break the
> connections
> between the hardline running to the tower and the cable entrance to
> the shack
> during lightning season. Admittedly, I'm only running 500 W. When I
> can leave
> them more permanently connected I revert to type N.
>
> Wes N7WS
>
> On 9/17/2018 5:04 PM, [hidden email] wrote:
> > If you have a vector network analyzer you'll discover that BNC
> > connectors aren't all that great at VHF and above, l oss and
> > impedance vary with connector axial alignment because the bayonnet
>
> > shell doesn't support aligh the connector body very well. Strain
> relief
> > is extremely important with BNC connectors. TNC connectors are
> > far superior but not widely used.
> >
> >
> > While professionally installed N connectors have superb RF
> > characteristics, all too often they're improperly installed --
> even by
> > professionals -- leading to damaged connectors if the male pin is
>
> > misaligned, or unreliable contact if the pin or socket depth is
> just a
> > few millimeters less than the manufacturers specification. I use
> > only captive pin male N connectors, avoiding the most severe
> > problems. I never use female N connectors on cables, the N sockets
>
> > are much too fragile.
> >
> >
> > Its hard to beat high quality silver plated UHF connectors at HF
> and
> > 6 meters. But its important to use a tool to tighten them. That's
> a
> > small price to pay for a very reliable connector.
> >
> >
> > 73
> > Frank
> > W3LPL
> >
>
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> Message delivered to [hidden email]
>

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Jim Brown-10

Re: loss of RX sensitivity

In reply to this post by donovanf

On 9/18/2018 1:53 PM, [hidden email] wrote:
> What is its current selling price?

Frank,

I believe it's under $200. https://www.sdr-kits.net/VA5_Page

73, Jim

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Wes Stewart-2

Re: loss of RX sensitivity

In reply to this post by donovanf

Hi Frank,

Agreed.

See: https://www.sdr-kits.net/VA5_Page bottom of the page. Indicative prices in
USD $191.77

Wes

On 9/18/2018 1:53 PM, [hidden email] wrote:

> Hi Wes,
>
> Thanks for forwarding the information about DG5MK's new FA-VA5
> VNA. What is its current selling price?
>
> If you use many BNC connectors, you'll notice a distinct difference in
> connector quality especially above 100 MHz. Avoid using BNC male
> connectors with weak tension when you turn the bayonette
> to engage the connector. If the bayonette turns too easily it doesn't
> maintain sufficient engagement force to keep the RF connections
> in proper alignment.
>
> 73
> Frank
> W3LPL
>

ke9uw

Re: loss of RX sensitivity

In reply to this post by Wes Stewart-2

I've worn a BNC out on a Tek scope once or twice in 35 years...

Chuck Hawley
[hidden email]

Amateur Radio, KE9UW
aka Jack, BMW Motorcycles
________________________________________
From: [hidden email] [[hidden email]] on behalf of Wes Stewart [[hidden email]]
Sent: Tuesday, September 18, 2018 12:51 PM
To: [hidden email]
Subject: Re: [Elecraft] loss of RX sensitivity

It's difficult to argue with Frank's experience and expertise. That said, fools
rush in...

I own some network analyzers, 1) an N2PK which I built with type N connectors,
2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert AA-55 Zoom
with a SO239. Professionally, I've used analyzers with type N, 3.5mm (beadless
SMA) and K connectors. With the exception of the AA-55, which only goes to 55
MHz, all of these can be calibrated with "precision" calibration kits that can
cost thousands of dollars. So far, Frank is right, not a BNC in the bunch.

But that has changed with the introduction of the DG5MK's FA-VA5, one-port
vector analyzer. I am on the reserve list to buy one of these. The thing to
note is that it is supplied with a BNC connector. There has been a lot of
anguish, heartburn, etc about this on the VNWA Yahoo group but the consensus is
that it will be fine and BNC calibration kit has been developed and tested
without issue. https://www.youtube.com/watch?v=X8Z7veGV57o

There are tens of thousands of BNCs on oscilloscopes and other instruments and
I've seldom had an issue with them in 30+ years of lab work. For quick
disconnect I also use short jumper cables with BNCs to break the connections
between the hardline running to the tower and the cable entrance to the shack
during lightning season. Admittedly, I'm only running 500 W. When I can leave
them more permanently connected I revert to type N.

Wes N7WS
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Chuck, KE9UW

Elecraft mailing list

Re: loss of RX sensitivity

In reply to this post by Drew AF2Z

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, [hidden email] wrote:

> Message: 1
> Date: Mon, 17 Sep 2018 16:45:10 -0700
> From: Walter Underwood <[hidden email]>
> To: "[hidden email]" <[hidden email]>
> Subject: Re: [Elecraft] loss of RX sensitivity
> Message-ID: <[hidden email]>
> 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)

--
Created on and sent from a Unix like PC running and using free and open source software.
::

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Elecraft mailing list

Re: loss of RX sensitivity

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 <[hidden email]> 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, [hidden email] wrote:
>> Message: 1
>> Date: Mon, 17 Sep 2018 16:45:10 -0700
>> From: Walter Underwood <[hidden email]>
>> To: "[hidden email]" <[hidden email]>
>> Subject: Re: [Elecraft] loss of RX sensitivity
>> Message-ID: <[hidden email]>
>> 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)

ke9uw

Re: loss of RX sensitivity

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 <[hidden email]> 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 <[hidden email]> 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, [hidden email] wrote:
>>> Message: 1
>>> Date: Mon, 17 Sep 2018 16:45:10 -0700
>>> From: Walter Underwood <[hidden email]>
>>> To: "[hidden email]" <[hidden email]>
>>> Subject: Re: [Elecraft] loss of RX sensitivity
>>> Message-ID: <[hidden email]>
>>> 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)
>
> --
> Created on and sent from a Unix like PC running and using free and open source software.
> ::
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Chuck, KE9UW

Elecraft mailing list

Re: loss of RX sensitivity

No, BNC's and N's do not inter-mate, not without damage.

Yes, you can push a N plug into a BNC socket, but the BNC socket will be
permanently damaged if you push hard enough for it not to fall out
unexpectedly. Plus the mismatch will be bad. But in an emergency?

Yes, the dimensions of the actual RF connector interface are similar,
but there is a major difference in the dielectric arrangements.

N's are "weather resistant" (some more so than others) but not "water
proof". BNC's of course are neither. (And neither are SO239/PL259's!)

73.

Dave G0WBX.

On 19/09/18 15:24, hawley, charles j jr wrote:
> 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

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Eric Swartz - WA6HHQ

Re: loss of RX sensitivity

Administrator

Lets close this thread - we are -way- past the max posting number limit for a
single topic.

Folks - I am not always able to watch the list in real time. Please self limit
on OT discussions like this. Once you hit 5-10 emails (at most) please take it
off list. You do not need to wait for me to step in. :-)

73,
Eric
List moderator, from time to time..)
/elecraft.com/

On 9/19/2018 9:12 AM, Dave B via Elecraft wrote:
> No, BNC's and N's do not inter-mate, not without damage.
>

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