Low-loss 50 Ohm coaxial cables + connectors for them?

[Vitaliy]

Hello,
Can someone please explain me how the coaxial cables work?
I'm looking for low loss BNC and SMA cables - 50 Ohm. Low loss is a
requirement, and as long as the price is not $1/ft for 500ft, any
reasonable price is ok. Most of my applications are <200MHz.

I see here http://www.gme.net.au/land/antennas/coax_cables.php
that RG58AU is a low loss BNC
from the data here http://www.ssbusa.com/comaircom.html
RG 213 seems to have even lower loss value


Now, on that last website ECOFLEX has even lower db loss. Ecoflex 10
can work with BNC, does it mean I can use it as conventional BNC cable,
just with low loss?

I read the BNC connectors are for average speed and SMA connectors are
for high-speed. Is it true? And can I place BNC, SMA and SMB connectors
on the cable from the same spool?

Thanks,
Vitaliy

 

[Phil Allison]

"Vitaliy" <[email protected]

Hello,
Can someone please explain me how the coaxial cables work?

** Mr wiki will do that for you:

http://en.wikipedia.org/wiki/Coaxial_cable

I'm looking for low loss BNC and SMA cables - 50 Ohm

** What is the application ?

Low loss is a requirement,

** What is the application ?

and as long as the price is not $1/ft for 500ft, any
reasonable price is ok.

** Low loss co-ax does not grow on trees.

Most of my applications are <200MHz.

** What is the application ?

RF or data ??

I read the BNC connectors are for average speed and SMA connectors are
for high-speed. Is it true?

** Hmmm - looks like it IS data and the OP = a "cable guy".

And can I place BNC, SMA and SMB connectors
on the cable from the same spool?

** QED.




......... Phil

 

[dmm]

Hello,
Can someone please explain me how the coaxial cables work?
I'm looking for low loss BNC and SMA cables - 50 Ohm. Low loss is a
requirement, and as long as the price is not $1/ft for 500ft, any
reasonable price is ok. Most of my applications are <200MHz.

How much loss can you tolerate? What are the frequencies your application
will be using? What is your RF budget? What distances will you be transmitting
your signal(s)? What will you be transmitting, RF or data? Do you need to run
the coax around tight corners? Do you need coax that is low smoking and free
of halides?

All coaxial cables (and connectors) exhibit attenuation (loss) over distance.
Do you consider $1/ft too expensive or too cheap?

I see here http://www.gme.net.au/land/antennas/coax_cables.php
that RG58AU is a low loss BNC

RG58AU is a type of coaxial cable. BNC is a type of connector. Distributors
that describe a BNC coax cable are talking about a cable that is terminated
with one or more BNC connectors.

Many BNC connector manufacturers have versions of their connectors
for crimping, soldering, or just screwing them onto the prepared RG58 cable.

from the data here http://www.ssbusa.com/comaircom.html
RG 213 seems to have even lower loss value

Yes, but it has a larger diameter than RG58 and is more rigid. I recommend
using crimp connectors to terminate RG213 coax because soldering the terminal
pin is a bugger without melting the dielectric slightly. And it takes practice.

Now, on that last website ECOFLEX has even lower db loss. Ecoflex 10
can work with BNC, does it mean I can use it as conventional BNC cable,
just with low loss?

Yes if connectors are available, and its probably a good deal more expensive too.
And 10mm diameter as opposed to about 6.5mm to 7mm for RG58 (I think)
But with the extra copper shield the ECOFLEX 10 will be somewhat more rigid
than the RG58.

I read the BNC connectors are for average speed and SMA connectors are
for high-speed. Is it true? And can I place BNC, SMA and SMB connectors
on the cable from the same spool?

What is "average speed" and "high speed"? The simple answer is to ask the
cable manufacturer/distributor which connector is suitable for the cable for
your application. They should have a list of preferred connector manufacturers
and any suitable connectors.

 

[Vitaliy]

How much loss can you tolerate? What are the frequencies your application
will be using? What is your RF budget? What distances will you be transmitting
your signal(s)? What will you be transmitting, RF or data? Do you need to run
the coax around tight corners? Do you need coax that is low smoking and free
of halides?

Right now we are using RG58, so it's about 16dB for 100m, slashing that
by 8 dB would be good.
The frequencies are anywhere between 5MHz and 500MHz.
I'm looking at somewhere ~$400 for 500ft. Distances - 1 to 3 meters
(maybe 1 or 2 10m ones).
I will be transmitting data and RF.
I don't see the need for tight corners at this point, but it would be
"nice to have" option.
No requirement for low smoking/free of halides, but would be
"nice-to-have".

All coaxial cables (and connectors) exhibit attenuation (loss) over distance.
Do you consider $1/ft too expensive or too cheap?


RG58AU is a type of coaxial cable. BNC is a type of connector. Distributors
that describe a BNC coax cable are talking about a cable that is terminated
with one or more BNC connectors.

Many BNC connector manufacturers have versions of their connectors
for crimping, soldering, or just screwing them onto the prepared RG58 cable.

Therefore, if, for example, I buy Belden cable, I can just buy BNC, SMB
or SMA connectors for that particular cable?

Yes, but it has a larger diameter than RG58 and is more rigid. I recommend
using crimp connectors to terminate RG213 coax because soldering the terminal
pin is a bugger without melting the dielectric slightly. And it takes practice.

I was also thinking about buying crimp connectors, smothing like this
http://www.integratednetworkcable.com/productDetailsPopUp.asp?idproduct=1071
or from here
http://www.danimex.com/Default.aspx?ID=1363

 

[Guest]

Something strange about this apparently sophisticated app and yet needing
all this basic info...

 

[Phil Allison]

"Vitaliy"

Right now we are using RG58, so it's about 16dB for 100m, slashing that
by 8 dB would be good.

** Why ?

The frequencies are anywhere between 5MHz and 500MHz.
I'm looking at somewhere ~$400 for 500ft. Distances - 1 to 3 meters
(maybe 1 or 2 10m ones).

** With such short runs you have no issue with cable loss at all.



........ Phil

 

[Vitaliy]

"Vitaliy"


** Why ?

Because with the biomedical equipment we are testing - we prefer to
have the minimal loss possible. And another reason I'm looking into
this because we have some RG58, RG58AU, RG174, RG59 (75Ohm, which we
don't need/can't use, but people still try to use), so I would like to
keep everything to one type only, if possible, to avoid confusion. And
since I'm getting this one type only, I would like to have the best one
possible.

** With such short runs you have no issue with cable loss at all.

That's the idea I was coming to after reading on the subject... But,
would I be able to use RG213 for both RF and data? Most of my signals
are data. RF signal I currently have is 10Vp-p (0 to 80MHz), it could
be greater voltage/frequency in the future.

Thanks,
Vitaliy

 

[Peter Bennett]

That's the idea I was coming to after reading on the subject... But,
would I be able to use RG213 for both RF and data? Most of my signals
are data. RF signal I currently have is 10Vp-p (0 to 80MHz), it could
be greater voltage/frequency in the future.

Thanks,
Vitaliy

If the equipment is rack-mounted, and the cables are permanently
attached, and ty-wrapped in place to prevent undue strain on the BNC
connectors, RG-213 or other large cable may be usable.

However, if the cables will be frequently connected and disconnected,
re-routed, tripped over, etc, I'd stick with RG58 (or some variation
thereof). RG-213 and other 0.4" cables are just too stiff for
portable patch cord use.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
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Vancouver Power Squadron: http://vancouver.powersquadron.ca

 

[atec77]

http://www.radiobooks.com/products/rf9f10.htm
9914 "flex" is about the best "heavy" coax you might consider
most 9913 is hollow and will collapse under more than minimal motion ,
9914 is a full foam dialectic which handles motion very well.

In a thinner material perhaps a slightly thinner rg6 quadsheild in a
fuly spec cable or thinner yet possibly one of the airframe
designations from Gore
http://www.gore.com/en_xx/products/cables/microwave/aircraft/index.html
A call to matchmaster (02 9153 6666) would be in order for some
salient advice

Good luck

 

[Vitaliy]

If the equipment is rack-mounted, and the cables are permanently

attached, and ty-wrapped in place to prevent undue strain on the BNC
connectors, RG-213 or other large cable may be usable.

However, if the cables will be frequently connected and disconnected,
re-routed, tripped over, etc, I'd stick with RG58 (or some variation
thereof). RG-213 and other 0.4" cables are just too stiff for
portable patch cord use.

Thanks, I'll look for something less stiff then RG213 then.

http://www.radiobooks.com/products/rf9f10.htm
9914 "flex" is about the best "heavy" coax you might consider
most 9913 is hollow and will collapse under more than minimal motion ,
9914 is a full foam dialectic which handles motion very well.

In a thinner material perhaps a slightly thinner rg6 quadsheild in a
fuly spec cable or thinner yet possibly one of the airframe
designations from Gore
http://www.gore.com/en_xx/products/cables/microwave/aircraft/index.html
A call to matchmaster (02 9153 6666) would be in order for some
salient advice

I contacted raiobooks for now.


Thanks,
Vitaliy