[Elecraft] K3 loss of rx signal

[David Olean]

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, donovanf at starpower.net 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" <ron at cobi.biz>
> To: donovanf at starpower.net, "Elecraft Reflector" <elecraft at mailman.qth.net>
> 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:elecraft-bounces at mailman.qth.net] On Behalf Of
> donovanf at starpower.net
> 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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