JG
Joseph Gray
Sat, Apr 9, 2011 10:53 PM
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
I want to use these isolated BNC connectors for a frequency
distribution amp. What do you think?
I'm still trying to find some old Ethernet cards for the transformers.
I know the cards will have BNC connectors, but the hub has eight
matched BNC connectors, so using them would be preferrable.
Joe Gray
W5JG
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
I want to use these isolated BNC connectors for a frequency
distribution amp. What do you think?
I'm still trying to find some old Ethernet cards for the transformers.
I know the cards will have BNC connectors, but the hub has eight
matched BNC connectors, so using them would be preferrable.
Joe Gray
W5JG
SW
Stan, W1LE
Sat, Apr 9, 2011 11:32 PM
Hello Joe,
It probably is a 50 ohm BNC female connector.
Check out a male loose connector with a known 50 ohm center pin.
Does the male pin fit the female nicely ?
I have rarely seen a 75 ohm BNC center pin, but they are out there.
I have never seen a 93 ohm BNC center pin. (never looked for them.)
If you apply a true 75 ohm BNC male connector to a 50 ohm BNC female it
may not mate properly with a
low resistance joint. ie. poor mechanical fit.
If you apply a 50 ohm male BNC into a 75 ohm BNC female, you will
probably destroy the female center pin.
Cost wise, the 50 ohm BNC connectors are the least expensive, so that is
what manufacturers use.
For most applications the electrical length of the center pin is a very
small part of a wavelength,
so there is only a very small impact on the impedance, on the rare
occasion impedance is of concern.
Stan, W1LE
On 4/9/2011 6:53 PM, Joseph Gray wrote:
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
I want to use these isolated BNC connectors for a frequency
distribution amp. What do you think?
I'm still trying to find some old Ethernet cards for the transformers.
I know the cards will have BNC connectors, but the hub has eight
matched BNC connectors, so using them would be preferrable.
Joe Gray
W5JG
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hello Joe,
It probably is a 50 ohm BNC female connector.
Check out a male loose connector with a known 50 ohm center pin.
Does the male pin fit the female nicely ?
I have rarely seen a 75 ohm BNC center pin, but they are out there.
I have never seen a 93 ohm BNC center pin. (never looked for them.)
If you apply a true 75 ohm BNC male connector to a 50 ohm BNC female it
may not mate properly with a
low resistance joint. ie. poor mechanical fit.
If you apply a 50 ohm male BNC into a 75 ohm BNC female, you will
probably destroy the female center pin.
Cost wise, the 50 ohm BNC connectors are the least expensive, so that is
what manufacturers use.
For most applications the electrical length of the center pin is a very
small part of a wavelength,
so there is only a very small impact on the impedance, on the rare
occasion impedance is of concern.
Stan, W1LE
On 4/9/2011 6:53 PM, Joseph Gray wrote:
> I have an old Arcnet hub that I want to salvage the isolated BNC
> connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
> and 75 Ohm versions of BNC connectors, but the ones from the hub look
> like a 50 Ohm BNC to me.
>
> I want to use these isolated BNC connectors for a frequency
> distribution amp. What do you think?
>
> I'm still trying to find some old Ethernet cards for the transformers.
> I know the cards will have BNC connectors, but the hub has eight
> matched BNC connectors, so using them would be preferrable.
>
> Joe Gray
> W5JG
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
AM
Alan Melia
Sat, Apr 9, 2011 11:39 PM
Hi Stan this one has been covered before the pins are the same size the
difference is in the amount of dielectric round the socket in the
female....the 75 ohm one hase the socket poking free of the ptfe and on the
50 ohm it is flush with the end. The the centre connectors mate correctly
together.
Alan G3NYK
----- Original Message -----
From: "Stan, W1LE" stanw1le@verizon.net
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, April 10, 2011 12:32 AM
Subject: Re: [time-nuts] BNC question
Hello Joe,
It probably is a 50 ohm BNC female connector.
Check out a male loose connector with a known 50 ohm center pin.
Does the male pin fit the female nicely ?
I have rarely seen a 75 ohm BNC center pin, but they are out there.
I have never seen a 93 ohm BNC center pin. (never looked for them.)
If you apply a true 75 ohm BNC male connector to a 50 ohm BNC female it
may not mate properly with a
low resistance joint. ie. poor mechanical fit.
If you apply a 50 ohm male BNC into a 75 ohm BNC female, you will
probably destroy the female center pin.
Cost wise, the 50 ohm BNC connectors are the least expensive, so that is
what manufacturers use.
For most applications the electrical length of the center pin is a very
small part of a wavelength,
so there is only a very small impact on the impedance, on the rare
occasion impedance is of concern.
Stan, W1LE
On 4/9/2011 6:53 PM, Joseph Gray wrote:
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
I want to use these isolated BNC connectors for a frequency
distribution amp. What do you think?
I'm still trying to find some old Ethernet cards for the transformers.
I know the cards will have BNC connectors, but the hub has eight
matched BNC connectors, so using them would be preferrable.
Joe Gray
W5JG
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
and follow the instructions there.
and follow the instructions there.
Hi Stan this one has been covered before the pins are the same size the
difference is in the amount of dielectric round the socket in the
female....the 75 ohm one hase the socket poking free of the ptfe and on the
50 ohm it is flush with the end. The the centre connectors mate correctly
together.
Alan G3NYK
----- Original Message -----
From: "Stan, W1LE" <stanw1le@verizon.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Sent: Sunday, April 10, 2011 12:32 AM
Subject: Re: [time-nuts] BNC question
> Hello Joe,
>
> It probably is a 50 ohm BNC female connector.
>
> Check out a male loose connector with a known 50 ohm center pin.
> Does the male pin fit the female nicely ?
>
> I have rarely seen a 75 ohm BNC center pin, but they are out there.
> I have never seen a 93 ohm BNC center pin. (never looked for them.)
>
> If you apply a true 75 ohm BNC male connector to a 50 ohm BNC female it
> may not mate properly with a
> low resistance joint. ie. poor mechanical fit.
>
> If you apply a 50 ohm male BNC into a 75 ohm BNC female, you will
> probably destroy the female center pin.
>
> Cost wise, the 50 ohm BNC connectors are the least expensive, so that is
> what manufacturers use.
> For most applications the electrical length of the center pin is a very
> small part of a wavelength,
> so there is only a very small impact on the impedance, on the rare
> occasion impedance is of concern.
>
> Stan, W1LE
>
>
>
>
>
>
> On 4/9/2011 6:53 PM, Joseph Gray wrote:
> > I have an old Arcnet hub that I want to salvage the isolated BNC
> > connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
> > and 75 Ohm versions of BNC connectors, but the ones from the hub look
> > like a 50 Ohm BNC to me.
> >
> > I want to use these isolated BNC connectors for a frequency
> > distribution amp. What do you think?
> >
> > I'm still trying to find some old Ethernet cards for the transformers.
> > I know the cards will have BNC connectors, but the hub has eight
> > matched BNC connectors, so using them would be preferrable.
> >
> > Joe Gray
> > W5JG
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
M
mikes@flatsurface.com
Sat, Apr 9, 2011 11:51 PM
At 06:53 PM 4/9/2011, Joseph Gray wrote...
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
The ARCNET spec states: "The MIC for use with coaxial cable is a
conventional BNC per MIL-STD-348A." If you look at that spec, it's for
50 Ohm connectors. 75 Ohm ones don't have the insulator around the
center socket. Since ARCNET only ran at 2.5 MHz, the mismatch
apparently didn't matter.
At 06:53 PM 4/9/2011, Joseph Gray wrote...
>I have an old Arcnet hub that I want to salvage the isolated BNC
>connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
>and 75 Ohm versions of BNC connectors, but the ones from the hub look
>like a 50 Ohm BNC to me.
The ARCNET spec states: "The MIC for use with coaxial cable is a
conventional BNC per MIL-STD-348A." If you look at that spec, it's for
50 Ohm connectors. 75 Ohm ones don't have the insulator around the
center socket. Since ARCNET only ran at 2.5 MHz, the mismatch
apparently didn't matter.
PS
paul swed
Sun, Apr 10, 2011 12:00 AM
should work just fine as long as the connectors a good fit. Suspect it is.
On Sat, Apr 9, 2011 at 7:51 PM, Mike S mikes@flatsurface.com wrote:
At 06:53 PM 4/9/2011, Joseph Gray wrote...
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
The ARCNET spec states: "The MIC for use with coaxial cable is a
conventional BNC per MIL-STD-348A." If you look at that spec, it's for 50
Ohm connectors. 75 Ohm ones don't have the insulator around the center
socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't
matter.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
should work just fine as long as the connectors a good fit. Suspect it is.
On Sat, Apr 9, 2011 at 7:51 PM, Mike S <mikes@flatsurface.com> wrote:
> At 06:53 PM 4/9/2011, Joseph Gray wrote...
>
> I have an old Arcnet hub that I want to salvage the isolated BNC
>> connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
>> and 75 Ohm versions of BNC connectors, but the ones from the hub look
>> like a 50 Ohm BNC to me.
>>
>
> The ARCNET spec states: "The MIC for use with coaxial cable is a
> conventional BNC per MIL-STD-348A." If you look at that spec, it's for 50
> Ohm connectors. 75 Ohm ones don't have the insulator around the center
> socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently didn't
> matter.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
MD
Magnus Danielson
Sun, Apr 10, 2011 11:30 AM
On 04/10/2011 01:51 AM, Mike S wrote:
At 06:53 PM 4/9/2011, Joseph Gray wrote...
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
The ARCNET spec states: "The MIC for use with coaxial cable is a
conventional BNC per MIL-STD-348A." If you look at that spec, it's for
50 Ohm connectors. 75 Ohm ones don't have the insulator around the
center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
didn't matter.
Risetime is the key aspect. If the impedance missmatch is sufficiently
small compared to the rise-time, it has no significant effect.
As I recall it ARCNET wasn't running at very high speeds and hence no
need for short rise-times.
Cheers,
Magnus
On 04/10/2011 01:51 AM, Mike S wrote:
> At 06:53 PM 4/9/2011, Joseph Gray wrote...
>> I have an old Arcnet hub that I want to salvage the isolated BNC
>> connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
>> and 75 Ohm versions of BNC connectors, but the ones from the hub look
>> like a 50 Ohm BNC to me.
>
> The ARCNET spec states: "The MIC for use with coaxial cable is a
> conventional BNC per MIL-STD-348A." If you look at that spec, it's for
> 50 Ohm connectors. 75 Ohm ones don't have the insulator around the
> center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
> didn't matter.
Risetime is the key aspect. If the impedance missmatch is sufficiently
small compared to the rise-time, it has no significant effect.
As I recall it ARCNET wasn't running at very high speeds and hence no
need for short rise-times.
Cheers,
Magnus
BG
Bruce Griffiths
Sun, Apr 10, 2011 11:44 AM
On 04/10/2011 01:51 AM, Mike S wrote:
At 06:53 PM 4/9/2011, Joseph Gray wrote...
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
The ARCNET spec states: "The MIC for use with coaxial cable is a
conventional BNC per MIL-STD-348A." If you look at that spec, it's for
50 Ohm connectors. 75 Ohm ones don't have the insulator around the
center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
didn't matter.
Risetime is the key aspect. If the impedance missmatch is sufficiently
small compared to the rise-time, it has no significant effect.
As I recall it ARCNET wasn't running at very high speeds and hence no
need for short rise-times.
Cheers,
Magnus
There's also the minor issue of 0.7mm and 0.9mm diameter centre pin BNC
variants.
They do exist, I've seen hundreds of them.
Bruce
Magnus Danielson wrote:
> On 04/10/2011 01:51 AM, Mike S wrote:
>> At 06:53 PM 4/9/2011, Joseph Gray wrote...
>>> I have an old Arcnet hub that I want to salvage the isolated BNC
>>> connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
>>> and 75 Ohm versions of BNC connectors, but the ones from the hub look
>>> like a 50 Ohm BNC to me.
>>
>> The ARCNET spec states: "The MIC for use with coaxial cable is a
>> conventional BNC per MIL-STD-348A." If you look at that spec, it's for
>> 50 Ohm connectors. 75 Ohm ones don't have the insulator around the
>> center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
>> didn't matter.
>
> Risetime is the key aspect. If the impedance missmatch is sufficiently
> small compared to the rise-time, it has no significant effect.
>
> As I recall it ARCNET wasn't running at very high speeds and hence no
> need for short rise-times.
>
> Cheers,
> Magnus
>
There's also the minor issue of 0.7mm and 0.9mm diameter centre pin BNC
variants.
They do exist, I've seen hundreds of them.
Bruce
MD
Magnus Danielson
Sun, Apr 10, 2011 12:41 PM
On 04/10/2011 01:44 PM, Bruce Griffiths wrote:
On 04/10/2011 01:51 AM, Mike S wrote:
At 06:53 PM 4/9/2011, Joseph Gray wrote...
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
The ARCNET spec states: "The MIC for use with coaxial cable is a
conventional BNC per MIL-STD-348A." If you look at that spec, it's for
50 Ohm connectors. 75 Ohm ones don't have the insulator around the
center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
didn't matter.
Risetime is the key aspect. If the impedance missmatch is sufficiently
small compared to the rise-time, it has no significant effect.
As I recall it ARCNET wasn't running at very high speeds and hence no
need for short rise-times.
Cheers,
Magnus
There's also the minor issue of 0.7mm and 0.9mm diameter centre pin BNC
variants.
They do exist, I've seen hundreds of them.
These days there exists a standard variant of the BNC for 75 Ohm which
is mechanical compatible with 50 Ohm. So that is what I recommend using.
75 Ohm BNC dominate with margin over 50 Ohm BNC at work. Our rise-times
makes connector-choices more relevant.
Cheers,
Magnus
On 04/10/2011 01:44 PM, Bruce Griffiths wrote:
> Magnus Danielson wrote:
>> On 04/10/2011 01:51 AM, Mike S wrote:
>>> At 06:53 PM 4/9/2011, Joseph Gray wrote...
>>>> I have an old Arcnet hub that I want to salvage the isolated BNC
>>>> connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
>>>> and 75 Ohm versions of BNC connectors, but the ones from the hub look
>>>> like a 50 Ohm BNC to me.
>>>
>>> The ARCNET spec states: "The MIC for use with coaxial cable is a
>>> conventional BNC per MIL-STD-348A." If you look at that spec, it's for
>>> 50 Ohm connectors. 75 Ohm ones don't have the insulator around the
>>> center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
>>> didn't matter.
>>
>> Risetime is the key aspect. If the impedance missmatch is sufficiently
>> small compared to the rise-time, it has no significant effect.
>>
>> As I recall it ARCNET wasn't running at very high speeds and hence no
>> need for short rise-times.
>>
>> Cheers,
>> Magnus
>>
> There's also the minor issue of 0.7mm and 0.9mm diameter centre pin BNC
> variants.
> They do exist, I've seen hundreds of them.
These days there exists a standard variant of the BNC for 75 Ohm which
is mechanical compatible with 50 Ohm. So that is what I recommend using.
75 Ohm BNC dominate with margin over 50 Ohm BNC at work. Our rise-times
makes connector-choices more relevant.
Cheers,
Magnus
GB
Greg Broburg
Sun, Apr 10, 2011 3:25 PM
From what I recall from our candle lit lab, the 75 ohm
BNCs had a slightly larger pin and would open up the
50 ohm females just a skoosh so when you put a
50 ohm, into a 50 ohm that had been tweaked by a
75 ohm, they were noisy or intermittent.
Greg
On 4/10/2011 5:30 AM, Magnus Danielson wrote:
On 04/10/2011 01:51 AM, Mike S wrote:
At 06:53 PM 4/9/2011, Joseph Gray wrote...
I have an old Arcnet hub that I want to salvage the isolated BNC
connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
and 75 Ohm versions of BNC connectors, but the ones from the hub look
like a 50 Ohm BNC to me.
The ARCNET spec states: "The MIC for use with coaxial cable is a
conventional BNC per MIL-STD-348A." If you look at that spec, it's for
50 Ohm connectors. 75 Ohm ones don't have the insulator around the
center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
didn't matter.
Risetime is the key aspect. If the impedance missmatch is sufficiently
small compared to the rise-time, it has no significant effect.
As I recall it ARCNET wasn't running at very high speeds and hence no
need for short rise-times.
Cheers,
Magnus
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
From what I recall from our candle lit lab, the 75 ohm
BNCs had a slightly larger pin and would open up the
50 ohm females just a skoosh so when you put a
50 ohm, into a 50 ohm that had been tweaked by a
75 ohm, they were noisy or intermittent.
Greg
On 4/10/2011 5:30 AM, Magnus Danielson wrote:
> On 04/10/2011 01:51 AM, Mike S wrote:
>> At 06:53 PM 4/9/2011, Joseph Gray wrote...
>>> I have an old Arcnet hub that I want to salvage the isolated BNC
>>> connectors from. Arcnet used 93 Ohm coax. I know that there are 50 Ohm
>>> and 75 Ohm versions of BNC connectors, but the ones from the hub look
>>> like a 50 Ohm BNC to me.
>>
>> The ARCNET spec states: "The MIC for use with coaxial cable is a
>> conventional BNC per MIL-STD-348A." If you look at that spec, it's for
>> 50 Ohm connectors. 75 Ohm ones don't have the insulator around the
>> center socket. Since ARCNET only ran at 2.5 MHz, the mismatch apparently
>> didn't matter.
>
> Risetime is the key aspect. If the impedance missmatch is sufficiently
> small compared to the rise-time, it has no significant effect.
>
> As I recall it ARCNET wasn't running at very high speeds and hence no
> need for short rise-times.
>
> Cheers,
> Magnus
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
DJ
David J Taylor
Sun, Apr 10, 2011 4:00 PM
I had remembered that it was a 75 ohm that would damage a
50 ohm socket. This article states that a 50 ohm would
damage a 75 ohm socket.
Greg
Indeed, the 75-ohm will have the smaller inner, and hence may be damaged
by the larger pin on the 50-ohm connector.
David
GM8ARV
SatSignal software - quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
> I had remembered that it was a 75 ohm that would damage a
> 50 ohm socket. This article states that a 50 ohm would
> damage a 75 ohm socket.
>
> Greg
Indeed, the 75-ohm will have the smaller inner, and hence may be damaged
by the larger pin on the 50-ohm connector.
David
GM8ARV
--
SatSignal software - quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
