Hello,

Would you expect to see, in a practical sense, and meaningful difference
between RG6 with a copper plated steel center conductor vs an all copper
one, going from the antenna to a receiving scanner (50 foot run; 1 GHz max).

Tried to find some attenuation tables for this in Google, but had no luck:
Plenty for the coax cables themselves, but might you know of any chart links
that show attenuation for the different types of connectors ?

Thanks,
B.

Robert11 wrote:
Hello,

Would you expect to see, in a practical sense, and meaningful difference
between RG6 with a copper plated steel center conductor vs an all copper
one, going from the antenna to a receiving scanner (50 foot run; 1 GHz max).

Tried to find some attenuation tables for this in Google, but had no luck:
Plenty for the coax cables themselves, but might you know of any chart links
that show attenuation for the different types of connectors ?

No.

Connector loss is negligible (0.1dB) for all reasonable connectors.
The ohmic losses would be a tiny fraction of the ohmic loss in the cable
itself (i.e. the connector interface is a few mm long, compared to
meters of cable).

Skin depth at 1 GHz in copper is 2 microns (0.08 mil). 6.5 microns (.26
mil) at 100 MHz. Your copper clad steel is probably just as good as
solid copper (check the data sheet and see what the clad thickness is..
if it's 4-5 times the skin depth, it's the same as solid.

Also check the shield material (there's more of it, but if it's
aluminum, it's lower conductivity)

At higher frequencies, dielectric loss will be a goodly fraction of the
total cable loss. Again, the connector is very short, so its dielectric
loss is a tiny fraction of the overall cable loss.

Robert11 wrote:
Hello,

Would you expect to see, in a practical sense, and meaningful difference
between RG6 with a copper plated steel center conductor vs an all copper
one, going from the antenna to a receiving scanner (50 foot run; 1 GHz max).

Tried to find some attenuation tables for this in Google, but had no luck:
Plenty for the coax cables themselves, but might you know of any chart links
that show attenuation for the different types of connectors ?

Thanks,
B.

There will be no measurable electrical difference between copper clad
steel and pure copper center conductor.

There's no mechanism within any common type of RF connector which causes
any significant amount of loss. Various types can cause some impedance
mismatch, but not enough to cause a noticeable reduction of signal to
the receiver.

Roy Lewallen, W7EL

" There's no mechanism within any common type of RF connector which causes
any significant amount of loss. Various types can cause some impedance
mismatch, but not enough to cause a noticeable reduction of signal to the
receiver.


Since the OP was asking about frequencies up to 1GHz, I would be more
cautious about losses in connectors. Poorly assembled connectors can show
significant losses at 1GHz. Also I have come across connectors and adaptors
(SMA) that show loss for no apparent reason at a Gig or so., now whether
this is due to dielectric losses or some other factor I am not sure but
mechanically they appeared to be prefect. One particular SMA barrel had a
stable and repeatable loss of over 2dB, but was clean and gauged OK.

Some of the cheap PL259 connectors also use very poor dielectric which show
significant loss at even VHF.

Regards
Jeff

Jeff wrote:
" There's no mechanism within any common type of RF connector which causes
any significant amount of loss. Various types can cause some impedance
mismatch, but not enough to cause a noticeable reduction of signal to the
receiver.


Since the OP was asking about frequencies up to 1GHz, I would be more
cautious about losses in connectors. Poorly assembled connectors can show
significant losses at 1GHz. Also I have come across connectors and adaptors
(SMA) that show loss for no apparent reason at a Gig or so., now whether
this is due to dielectric losses or some other factor I am not sure but
mechanically they appeared to be prefect. One particular SMA barrel had a
stable and repeatable loss of over 2dB, but was clean and gauged OK.

Some of the cheap PL259 connectors also use very poor dielectric which show
significant loss at even VHF.

Regards
Jeff

I'm surprised at these reports, but not too much except for the 2 dB
connector. It must have had some internal corrosion, or perhaps
something like a helical internal contact causing an impedance mismatch
that would look like loss in a matched measurement system. (Some el
crappo UHF barrel adapters have found to be constructed that way.) I've
seen some awfully shoddy BNC connectors at ham conventions and wouldn't
use them for anything at all critical. But the OP asked if there was a
place he could find the losses of various kinds of connectors. I don't
believe there's any place you can go to find the losses of shoddily made
or improperly assembled connectors or adapters. Decently made and
properly assembled connectors of standard types show no appreciable loss
at 1 GHz. If loss is a concern, my advice is to buy name brand
connectors, and especially avoid the cheap stuff you see at places like
flea markets.

Roy Lewallen, W7EL

In message , Roy Lewallen
writes
Jeff wrote:
" There's no mechanism within any common type of RF connector which causes
any significant amount of loss. Various types can cause some
impedance mismatch, but not enough to cause a noticeable reduction
of signal to the receiver.
Since the OP was asking about frequencies up to 1GHz, I would be
more cautious about losses in connectors. Poorly assembled connectors
can show significant losses at 1GHz. Also I have come across
connectors and adaptors (SMA) that show loss for no apparent reason
at a Gig or so., now whether this is due to dielectric losses or some
other factor I am not sure but mechanically they appeared to be
prefect. One particular SMA barrel had a stable and repeatable loss
of over 2dB, but was clean and gauged OK.
Some of the cheap PL259 connectors also use very poor dielectric
which show significant loss at even VHF.
Regards
Jeff

I'm surprised at these reports, but not too much except for the 2 dB
connector. It must have had some internal corrosion, or perhaps
something like a helical internal contact causing an impedance mismatch
that would look like loss in a matched measurement system. (Some el
crappo UHF barrel adapters have found to be constructed that way.) I've
seen some awfully shoddy BNC connectors at ham conventions and wouldn't
use them for anything at all critical. But the OP asked if there was a
place he could find the losses of various kinds of connectors. I don't
believe there's any place you can go to find the losses of shoddily
made or improperly assembled connectors or adapters. Decently made and
properly assembled connectors of standard types show no appreciable
loss at 1 GHz. If loss is a concern, my advice is to buy name brand
connectors, and especially avoid the cheap stuff you see at places like
flea markets.

Roy Lewallen, W7EL


Even at 1GHz, I don't believe that you would get as much as 2dB of loss
even if you joined two pieces of coax by stripping the ends with a
knife, twisting the conductors together, and wrapping them in scotch
tape.
--
Ian

Hello,

First, let me say thanks to everyone for the replies and help.
New at this, and it seems these very basic questions of mine keep coming up
the more I look into it.
Great hobby, and really do appreciate the help, very much.
Super newsgroup for folks like me. Sure is a lot to learn re antennas;
reading the ARRL book on it now.

Would like to modify my question somewhat.
Was really surprised to learn about the copper on steel, vs all copper
center conductors on coax.
I thought the difference were only in types of shielding; not center
conductor construction, and that RG6, e.g., was RG6, at least concerning
attenuation and perhaps "quality". Guess not ?

I understand, and am aware of now, the skin effect depth
Will read up on it some more.

Question: any meaningful difference for the sw frequencies; say from 0.5 to
30 MHz ?
I have a sw receiving set also, and frankly, when i strung my coax for it, I
never considered the center conductor coax's construction.

Should I have, possibly ?

Thanks again,
Bob

-------------------

"Robert11" wrote in message
news
Hello,

Would you expect to see, in a practical sense, and meaningful difference
between RG6 with a copper plated steel center conductor vs an all copper
one, going from the antenna to a receiving scanner (50 foot run; 1 GHz
max).

Tried to find some attenuation tables for this in Google, but had no luck:
Plenty for the coax cables themselves, but might you know of any chart
links that show attenuation for the different types of connectors ?

Thanks,
B.

I'm surprised at these reports, but not too much except for the 2 dB
connector. It must have had some internal corrosion, or perhaps something
like a helical internal contact causing an impedance mismatch that would
look like loss in a matched measurement system. (Some el crappo UHF barrel
adapters have found to be constructed that way.) I've seen some awfully
shoddy BNC connectors at ham conventions and wouldn't use them for
anything at all critical. But the OP asked if there was a place he could
find the losses of various kinds of connectors. I don't believe there's
any place you can go to find the losses of shoddily made or improperly
assembled connectors or adapters. Decently made and properly assembled
connectors of standard types show no appreciable loss at 1 GHz. If loss is
a concern, my advice is to buy name brand connectors, and especially avoid
the cheap stuff you see at places like flea markets.

Roy Lewallen, W7EL


Even at 1GHz, I don't believe that you would get as much as 2dB of loss
even if you joined two pieces of coax by stripping the ends with a knife,
twisting the conductors together, and wrapping them in scotch tape.
--
Ian

The items in question were SMA barrel adaptors and as I said showed no signs
of damage, corrosion or spreading of the contacts and interface dimensions
were in spec

It is surprisingly easy to get significant loss at 1GHz and above, 2dB would
be very easy to achieve even when using what appears to be a 'good'
connection.

regards
Jeff

In message , Jeff
writes
I'm surprised at these reports, but not too much except for the 2 dB
connector. It must have had some internal corrosion, or perhaps something
like a helical internal contact causing an impedance mismatch that would
look like loss in a matched measurement system. (Some el crappo UHF barrel
adapters have found to be constructed that way.) I've seen some awfully
shoddy BNC connectors at ham conventions and wouldn't use them for
anything at all critical. But the OP asked if there was a place he could
find the losses of various kinds of connectors. I don't believe there's
any place you can go to find the losses of shoddily made or improperly
assembled connectors or adapters. Decently made and properly assembled
connectors of standard types show no appreciable loss at 1 GHz. If loss is
a concern, my advice is to buy name brand connectors, and especially avoid
the cheap stuff you see at places like flea markets.

Roy Lewallen, W7EL


Even at 1GHz, I don't believe that you would get as much as 2dB of loss
even if you joined two pieces of coax by stripping the ends with a knife,
twisting the conductors together, and wrapping them in scotch tape.
--
Ian

The items in question were SMA barrel adaptors and as I said showed no signs
of damage, corrosion or spreading of the contacts and interface dimensions
were in spec

It is surprisingly easy to get significant loss at 1GHz and above, 2dB would
be very easy to achieve even when using what appears to be a 'good'
connection.

regards
Jeff

I have to admit that I've routinely worked to 870MHz, and recently even
to 1003MHz, but rarely ventured higher. However, I've never found any
excessive loss in a connector which could not be accounted for by a
straightforward 'bad connection', ie usually a total or partial open or
short circuit, whether in the making off of the cable, or in the
construction of the connector itself. Honest!
--
Ian.

Ian Jackson wrote in
news
In message , Jeff
writes
I'm surprised at these reports, but not too much except for the 2 dB
connector. It must have had some internal corrosion, or perhaps
something like a helical internal contact causing an impedance
mismatch that would look like loss in a matched measurement system.
(Some el crappo UHF barrel adapters have found to be constructed
that way.) I've seen some awfully shoddy BNC connectors at ham
conventions and wouldn't use them for anything at all critical. But
the OP asked if there was a place he could find the losses of
various kinds of connectors. I don't believe there's any place you
can go to find the losses of shoddily made or improperly assembled
connectors or adapters. Decently made and properly assembled
connectors of standard types show no appreciable loss at 1 GHz. If
loss is a concern, my advice is to buy name brand connectors, and
especially avoid the cheap stuff you see at places like flea
markets.

Roy Lewallen, W7EL

snip
I have to admit that I've routinely worked to 870MHz, and recently
even to 1003MHz, but rarely ventured higher. However, I've never found
any excessive loss in a connector which could not be accounted for by
a straightforward 'bad connection', ie usually a total or partial open
or short circuit, whether in the making off of the cable, or in the
construction of the connector itself. Honest!


One thing, SMA connectors are rated for 500 connection cycles, I don’t know
what happens after that, but on test equipment 500 connections might happen
fairly fast. I know from experience that SMA is a connector that’s easy to
put on badly.

John Passaneau