On Sun,10/12/2014 6:32 PM, Acbross via Elecraft wrote:
Don't know where anyone got the idea that BNCs made for RG-8x we 75 ohm. I
worked in the tv industry for many years and we used hundreds of BNCs that were
made specifically for 75 ohm video. By the way, RG-59 not RG-79.
While you are
Thanks Jim
I was going to ask that exact question. For the amateur world, does it
make a difference if a 75 ohm connector is installed on a 50 ohm feedline.
You made it very clear for everyone. Thanks!
Mike va3mw
On Mon, Oct 13, 2014 at 12:15 PM, Jim Brown j...@audiosystemsgroup.com
wrote:
Jim,
It may not make a difference to performance on HF but it does matter
because the centre pins have different diameters of solder pot / crimp
barrel to match the cable impedance used. Also incorrectly mated
connectors risk damage to their centre connectors by forcing the
engagement. Use
Peter
The larger concern is that most of us have no way of being able to tell the
difference from a 50 ohm bnc to a 75 ohm bnc. We buy these online and at
flee markets, which is part of the reality.
Is there an easy way to tell them apart?
I assume the same is also true for N connectors which
On Mon,10/13/2014 9:30 AM, Peter Torry wrote:
It may not make a difference to performance on HF but it does matter
because the centre pins have different diameters of solder pot / crimp
barrel to match the cable impedance used.
What matters is that the connector match the physical dimensions
On Mon 13 Oct Jim Brown wrote:
the o.d. of the male tip. Although I have not studied the mechanical
Standard for 75 ohm BNCs, I would VERY surprised if the dimensions of
a proper 75 ohm connector would prevent it from mating with a proper
50 ohm connector. Have you studied such a spec? I'm
YES The 75 ohm series are UG-260/U connectors, the 50 ohm series is
the UG-88/U. If they don't have this stamped into the rear barrel of
the connector, THEY ARE Counterfeits or JUST PLAIN TRASH!
There is a lot of crap parts available at hamfests these days! Be
careful what you buy!!
The big difference of the 75 and 50 ohm connectors is the fit of the
connectors to the coax size, NOT the center pin size which is the same.
BNC connectors are really NOT constant impedance especially at VHF/UHF
frequencies like proper N series connectors are. This makes no
difference
On Mon,10/13/2014 10:34 AM, Rick M0LEP wrote:
especially if you're dealing with cheap plugs and sockets.
From my work on the AES Standards Committee Working Group on
Connectors, I can tell you that junk and even counterfeit connectors are
the problem, not the nominal Zo. Junk connectors of
Jim -
Good quality BNC connectors can be had from Amphenol and AMP. I
normally use AMP crimp-type connectors for BNC applications, have
_never_ had one fail, and I purchase them by the hundreds. Takes only a
few seconds to install one. One other good supplier of RF connectors
is Kings.
While you are entirely correct that there are 75 ohm and 50 ohm BNCs,
the difference DOES NOT MATTER at HF, because the connector is such a
small fraction of a wavelength and the difference is small.
I disagree ... *DO NOT MIX 75 and 50 Ohm connectors*. 50 Ohm male
connectors will split the
Although I have not studied the mechanical Standard for 75 ohm BNCs,
I would VERY surprised if the dimensions of a proper 75 ohm connector
would prevent it from mating with a proper 50 ohm connector. Have you
studied such a spec?
Yes, I have used both in the TV stations - 50 Ohm for RF
According to the specs in the RF Industires catalog, pages 7 and 14 in
the version I have here, the center pins of 50 ohm and 75 ohm BNC's
are indeed the same size: .053 +/-.001 inch.
The difference is Zo is generated by using dielectric in the 50 ohm
but none in the 75 ohm, and slight
According to the specs in the RF Industries catalog, pages 7 and 14 in
the version I have here, the center pins of 50 ohm and 75 ohm BNC's
are indeed the same size: .053 +/-.001 inch.
The difference is Zo is generated by using dielectric in the 50 ohm
but none in the 75 ohm, and slight
Hello Jim,
I quite agree that what matters is that the connector match the physical
dimensions of the cable.
Originally they didn't mate, 50 Ohm was 50 Ohm and 75 was 75.The pins
were different diameters, and there were warranty warnings to only use
the correct connectors with equipment
All,
And while the pin/receptacle dimensions are important to maintain physical
integrity, the characteristic impedance doesn't come into play unless you
experience a considerable phase length such as a 30 degree discontinuity at a
given frequency.
So at HF the phase length of the 70-50 Ω
On 10/13/2014 10:42 AM, Sandy Blaize wrote:
There is a lot of crap parts available at hamfests these days! Be
careful what you buy!!
Had cable problems with P3 when I first got it. Bob, K6XX, at Elecraft
and who I know well called me and said [only slightly tongue-in-cheek]
they'd send me
The practical answer is try to insert your coax into the bushing. RG-59 and
RG8X are the same size and RG-58 is smaller. If RG-58 is sloppy in the bushing
and RG-59 or RG8X fits then it is OK to use unless you are trying to get an
exact match for micro-wave. If you are a micro-wave engineer
: Re: [Elecraft] BNCs
On 10/13/2014 10:42 AM, Sandy Blaize wrote:
There is a lot of crap parts available at hamfests these days! Be
careful what you buy!!
Had cable problems with P3 when I first got it. Bob, K6XX, at Elecraft
and who I know well called me and said [only slightly tongue
12:49 PM
To: [hidden email]
Subject: Re: [Elecraft] BNCs
On 10/13/2014 10:42 AM, Sandy Blaize wrote:
There is a lot of crap parts available at hamfests these days! Be
careful what you buy!!
Had cable problems with P3 when I first got it. Bob, K6XX, at Elecraft
and who I know well
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