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K3 loss of rx signal

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donovanf

Re: K3 loss of rx signal

Hi Ron,

If you've ever used BNC connectors in a lab environment -- especially
above about 30 MHz -- you soon become aware of their shortcomings
especially if they don't fit snugly. I've never noticed BNC problems
at HF frequencies except for worn (or cheaply made) connectors that
fit very loosely.

I'm sure the Amphenol connectors are very high quality and perhaps
not as leaky and unreliable as generic (or worn) connectors

73
Frank
W3LPL

----- Original Message -----

From: "Ron D'Eau Claire" <[hidden email]>
To: [hidden email], "Elecraft Reflector" <[hidden email]>
Sent: Tuesday, April 4, 2017 9:09:32 PM
Subject: RE: [Elecraft] K3 loss of rx signal

Good point Frank.

Amphenol specs leakage for their BNC connectors at 3GHz where they claim 55
dB. By comparison they claim 90 dB at 3 GHz for their type N connectors.

I've never felt the need for the additional shielding in the shack.

Of course these are Amphenol specs. Any other brand may have any other level
of leakage. As many have noted, the extra price of a good connector is saved
many times over chasing bad cable connections later.

BNC specs
http://www.amphenolrf.com/connectors/bnc.html

N specs:
http://www.amphenolrf.com/connectors/n-type.html

73, Ron AC7AC

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of
[hidden email]
Sent: Monday, April 3, 2017 9:38 PM
To: Elecraft Reflector
Subject: Re: [Elecraft] K3 loss of rx signal

BNC connectors rate high for convenience and low for performance, especially
leakage performance.

BNC connector leakage typicallymeasures in the range from -25 to
-50 dB vs -60 to -90 dB for N connectors. Any BNC connector
that does not fit snugly should replaced and discarded

73
Frank
W3LPL

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David Olean

Re: K3 loss of rx signal

I would echo Frank's comments. I learned long ago that you never measure
antenna gain with any BNC connectors in the signal path. Each joint
would introduce intermittent loss depending on how much the cable
moved. They are not very stable at VHF frequencies. They sure are
convenient though for more simple tasks.

Dave K1WHS

On 4/4/2017 9:19 PM, [hidden email] wrote:

> Hi Ron,
>
>
> If you've ever used BNC connectors in a lab environment -- especially
> above about 30 MHz -- you soon become aware of their shortcomings
> especially if they don't fit snugly. I've never noticed BNC problems
> at HF frequencies except for worn (or cheaply made) connectors that
> fit very loosely.
>
>
> I'm sure the Amphenol connectors are very high quality and perhaps
> not as leaky and unreliable as generic (or worn) connectors
>
>
> 73
> Frank
> W3LPL
>
> ----- Original Message -----
>
> From: "Ron D'Eau Claire" <[hidden email]>
> To: [hidden email], "Elecraft Reflector" <[hidden email]>
> Sent: Tuesday, April 4, 2017 9:09:32 PM
> Subject: RE: [Elecraft] K3 loss of rx signal
>
> Good point Frank.
>
> Amphenol specs leakage for their BNC connectors at 3GHz where they claim 55
> dB. By comparison they claim 90 dB at 3 GHz for their type N connectors.
>
> I've never felt the need for the additional shielding in the shack.
>
> Of course these are Amphenol specs. Any other brand may have any other level
> of leakage. As many have noted, the extra price of a good connector is saved
> many times over chasing bad cable connections later.
>
> BNC specs
> http://www.amphenolrf.com/connectors/bnc.html
>
> N specs:
> http://www.amphenolrf.com/connectors/n-type.html
>
> 73, Ron AC7AC
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> [hidden email]
> Sent: Monday, April 3, 2017 9:38 PM
> To: Elecraft Reflector
> Subject: Re: [Elecraft] K3 loss of rx signal
>
> BNC connectors rate high for convenience and low for performance, especially
> leakage performance.
>
>
> BNC connector leakage typicallymeasures in the range from -25 to
> -50 dB vs -60 to -90 dB for N connectors. Any BNC connector
> that does not fit snugly should replaced and discarded
>
>
> 73
> Frank
> W3LPL
>
>
> ______________________________________________________________
> 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]
>

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Elecraft mailing list

Re: K3 loss of rx signal

In reply to this post by donovanf

I've pretty much standardized on Amphenol connectors.
It's worth paying a little more and having less headaches.

From: Ron D'Eau Claire <[hidden email]>
To: [hidden email]; 'Elecraft Reflector' <[hidden email]>
Sent: Tuesday, April 4, 2017 5:12 PM
Subject: Re: [Elecraft] K3 loss of rx signal

Good point Frank.

Amphenol specs leakage for their BNC connectors at 3GHz where they claim 55
dB. By comparison they claim 90 dB at 3 GHz for their type N connectors.

I've never felt the need for the additional shielding in the shack.

Of course these are Amphenol specs. Any other brand may have any other level
of leakage. As many have noted, the extra price of a good connector is saved
many times over chasing bad cable connections later.

BNC specs
http://www.amphenolrf.com/connectors/bnc.html

N specs:
http://www.amphenolrf.com/connectors/n-type.html

73, Ron AC7AC

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Barry K3NDM

Re: K3 loss of rx signal

In reply to this post by donovanf

Frank,
I have had intermittent problems with BNC and N connectors. It was a
really subtle thing. The connectors were for 75 Ohm connection vice 50
Ohms. That meant the center pin was thinner which caused intermittent
connections. After that, I've always checked to see that I didn't make
that mistake again.

73,
Barry
K3NDM

------ Original Message ------
From: [hidden email]
To: "Elecraft Reflector" <[hidden email]>
Sent: 4/4/2017 5:19:47 PM
Subject: Re: [Elecraft] K3 loss of rx signal

>Hi Ron,
>
>
>If you've ever used BNC connectors in a lab environment -- especially
>above about 30 MHz -- you soon become aware of their shortcomings
>especially if they don't fit snugly. I've never noticed BNC problems
>at HF frequencies except for worn (or cheaply made) connectors that
>fit very loosely.
>
>
>I'm sure the Amphenol connectors are very high quality and perhaps
>not as leaky and unreliable as generic (or worn) connectors
>
>
>73
>Frank
>W3LPL
>
>----- Original Message -----
>
>From: "Ron D'Eau Claire" <[hidden email]>
>To: [hidden email], "Elecraft Reflector"
><[hidden email]>
>Sent: Tuesday, April 4, 2017 9:09:32 PM
>Subject: RE: [Elecraft] K3 loss of rx signal
>
>Good point Frank.
>
>Amphenol specs leakage for their BNC connectors at 3GHz where they
>claim 55
>dB. By comparison they claim 90 dB at 3 GHz for their type N
>connectors.
>
>I've never felt the need for the additional shielding in the shack.
>
>Of course these are Amphenol specs. Any other brand may have any other
>level
>of leakage. As many have noted, the extra price of a good connector is
>saved
>many times over chasing bad cable connections later.
>
>BNC specs
>http://www.amphenolrf.com/connectors/bnc.html
>
>N specs:
>http://www.amphenolrf.com/connectors/n-type.html
>
>73, Ron AC7AC
>
>-----Original Message-----
>From: Elecraft [mailto:[hidden email]] On Behalf Of
>[hidden email]
>Sent: Monday, April 3, 2017 9:38 PM
>To: Elecraft Reflector
>Subject: Re: [Elecraft] K3 loss of rx signal
>
>BNC connectors rate high for convenience and low for performance,
>especially
>leakage performance.
>
>
>BNC connector leakage typicallymeasures in the range from -25 to
>-50 dB vs -60 to -90 dB for N connectors. Any BNC connector
>that does not fit snugly should replaced and discarded
>
>
>73
>Frank
>W3LPL
>
>
>______________________________________________________________
>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]

Jim Brown-10

Re: K3 loss of rx signal

In reply to this post by donovanf

On Tue,4/4/2017 2:19 PM, [hidden email] wrote:
> I'm sure the Amphenol connectors are very high quality and perhaps
> not as leaky and unreliable as generic (or worn) connectors

The problem with that is that it assumes that the Amphenol connector you
properly installed is mated to another Amphenol connector, properly
installed.

A few years ago, I added stubs to a couple of antennas for harmonic
suppression, carefully placing them for optimum suppression, but didn't
hear nearly as much suppression as I thought I should. One of the causes
was rectification and re-radiation, as you had posted (thank you VERY
much for that), but the other cause was leakage in the cabling that made
up my antenna switching, and in the switching itself. Harmonic
suppression can be a big deal if you're trying work SO2R on 40/80 and
40/20.

The next summer, I bought a spool of BuryFlex and a bag of 83-1SPs and
replaced every piece of coax in that system. I also replaced the 6x2
Array Solutions switch with the newest 4O3A 8x2 switch. Once that work
was complete, harmonic suppression provided by the stubs was
significantly better, and what I heard was down to the "gurgly" sounding
rectification you described.

73, Jim K9YC

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Jim

Re: K3 loss of rx signal

In reply to this post by LA7NO

I'm replying late to this subject as I've been out of town and have many digests to go thru...speaking of Amphenol BNC's: I have had continuing problems with the original cable to go from K3 to P3 from day one. Yes, those great folks at Elecraft sent me a replacement cable gratis, but I have to deal with this every time I'm on the radio. I've cleaned, tweaked and replaced, and the display problems come back eventually. I'm shopping for making my own, and want to use amphenol solder (clamp) style for RG-58. I've boiled it down to 31-2 and 31-212 (not 31-212RFX). On the technical drawings the pins are drawn as a different shape! I can't see any other difference except for price. I plan on also cabling to the RX ANT In. Several posts were made regarding this subject including a link to the general amphenol BNC page, without sharing which specific part you use. Could you please share the exact part you use and why? Thanks! Jim WN8A
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Bill Breeden

Re: K3 loss of rx signal

Jim,

I too had an issue with a couple of cables between my K3 and P3. Had to
wiggle the cable every few days to get rid of the extra noise on the
P3. Finally replaced the cable with a 3 foot Amphenol BNC cable, part
number 115101-30-36.00 and have never had the issue again. The cable is
made with LMR-100, which is skinny and flexible. It's currently in
stock at Mouser for $18.66.

73,

Bill - NA5DX

On 4/7/2017 11:09 AM, Jim LeFevre wrote:

> I'm replying late to this subject as I've been out of town and have many digests to go thru...speaking of Amphenol BNC's: I have had continuing problems with the original cable to go from K3 to P3 from day one. Yes, those great folks at Elecraft sent me a replacement cable gratis, but I have to deal with this every time I'm on the radio. I've cleaned, tweaked and replaced, and the display problems come back eventually. I'm shopping for making my own, and want to use amphenol solder (clamp) style for RG-58. I've boiled it down to 31-2 and 31-212 (not 31-212RFX). On the technical drawings the pins are drawn as a different shape! I can't see any other difference except for price. I plan on also cabling to the RX ANT In. Several posts were made regarding this subject including a link to the general amphenol BNC page, without sharing which specific part you use. Could you please share the exact part you use and why? Thanks! Jim WN8A
> ______________________________________________________________
> 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]
>

George Danner-2

Re: K3 loss of rx signal

Bill,
Try using a sharp soldering aid to "tighten" the female connector contact on
the K3 & P3.
Pry the female center contacts inward just a bit.
73
George
AI4VZ

-----Original Message-----
From: Bill Breeden
Sent: Friday, April 7, 2017 1:18 PM
To: Jim LeFevre
Cc: [hidden email]
Subject: Re: [Elecraft] K3 loss of rx signal

Jim,

I too had an issue with a couple of cables between my K3 and P3. Had to
wiggle the cable every few days to get rid of the extra noise on the
P3. Finally replaced the cable with a 3 foot Amphenol BNC cable, part
number 115101-30-36.00 and have never had the issue again. The cable is
made with LMR-100, which is skinny and flexible. It's currently in
stock at Mouser for $18.66.

73,

Bill - NA5DX

On 4/7/2017 11:09 AM, Jim LeFevre wrote:

> I'm replying late to this subject as I've been out of town and have many
> digests to go thru...speaking of Amphenol BNC's: I have had continuing
> problems with the original cable to go from K3 to P3 from day one. Yes,
> those great folks at Elecraft sent me a replacement cable gratis, but I
> have to deal with this every time I'm on the radio. I've cleaned, tweaked
> and replaced, and the display problems come back eventually. I'm shopping
> for making my own, and want to use amphenol solder (clamp) style for
> RG-58. I've boiled it down to 31-2 and 31-212 (not 31-212RFX). On the
> technical drawings the pins are drawn as a different shape! I can't see
> any other difference except for price. I plan on also cabling to the RX
> ANT In. Several posts were made regarding this subject including a link to
> the general amphenol BNC page, without sharing which specific part you
> use. Could you please share the exact part you use and why? Thanks! Jim
> WN8A