On Sun, 22 May 2016 14:07:42 +0100, Tim Streater
wrote:

In article , Andrew Gabriel
wrote:

In article ,
News writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com hub,
which I tried. It worked, but killed the speed.

Probably only 10Mbits/s.
ICBR, but I think hubs had vanished before 100Mbit ethernet became popular
(possibly because they can't convert speeds to perform interworking).

We have to watch the terminology. When I started with Ethernet (1983),
you used yellow coax as the backbone, at 10Mbps.

10Base5 / RG8?

Your backbone could be
up to 500m long and you could have extra 500m segments connected to it
via repeaters. Total end-to-end length between any two points not to
exceed 1500m.

And you still had to follow the 5-4-3 rule.

A repeater just streamed the bits through it, reshaping the signal -
that's all. No storage, and the first bit went out a bit-time or two
after receipt by the repeater, so a packet would span two cable
segments as it went down the wire. Repeaters only had two ports, IIRC.

I never saw a 10Base5 repeater.

If you wanted to go further than as described above, you needed to use
a bridge, which did store-and-forward. It read the whole packet in, and
then consulted its table of MAC addresses to see which port to send it
out on. You could thus connect several networks together in a simple
tree. If you made loops that way, then the bridges (which communicated
with each other) used spanning tree to detect loops and decide how to
disable enough ports to get you back to being a simple tree again.

I think these days what was then called a bridge is now called a
switch.

Sounds reasonable. ;-)

Not sure what a repeater is called now. Hub, possibly.

Or 'repeater'? ;-)

Then there was thinnet, still at 10Mbps but using thinner coax and
possibly shorter segments, and simpler connectors.

10Base2 and 185m [1] if I remember correctly and the 5-4-3 rules
applies. I used made up (not crimp) BNC connectors and never had a
problem with them.

Because of the shape of the building I had an 8 Port multiport
repeater with one port going to my room and 10 'servers / gateways'
and each of the other ports radiating around the building, typically
to different business zones (like 'Sales' or 'Admin').

Much better is twisted pair at 100 and 1000 Mbps, of course, simpler
connectors, much more reliable, no more worrying about bend radius of
your cabling,

Not sure about that?

or the reliability of the taps on your backbone.

Again, I used proper taps, not the 'vampire' type. ;-)

What's helped even more is the reduction in the size of the
electronics, and cost. One connection of a PC to ethernet when I was
first doing it required a whole card slot inside the PC,

'Network cards' are still in common use. ;-)

and for the
connection to the backbone a box about the size of three paperback
books stacked together, with a fat cable between the two.

Yes, the transceiver / TAP and the AUI 'drop cables' (max 50m I
think).

I started with a mixture of Token Ring and 'Omninet 1' via the Amstrad
3 user network starter kit that was a bit like the early Apple
networking. That then became LAN Manager / basic NetBIOS network
over thin Ethernet and because it was very simple was pretty fast (a
lower overhead than TCP/IP etc). Then we brought Netware and TCP/IP
into it etc.

They were the good days when you really had to know what you were
doing to even 'network' a PC. ;-)

Cheers, T i m

[1] And a minimum cable length of .6m or something, a rule I was able
to relay to a mate who ran a fairly big network and was having trouble
with when I pointed out the 6" Ethernet cables between his multi-port
repeaters were possibly the issue (and they were). ;-)

On 22/05/16 15:47, Tim Streater wrote:
In article , T i m
wrote:

On Sun, 22 May 2016 14:07:42 +0100, Tim Streater
wrote:

In article , Andrew Gabriel
wrote:

In article ,
News writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com
hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s.
ICBR, but I think hubs had vanished before 100Mbit ethernet became
popular
(possibly because they can't convert speeds to perform interworking).

We have to watch the terminology. When I started with Ethernet (1983),
you used yellow coax as the backbone, at 10Mbps.

10Base5 / RG8?

What's RG8?

Then there was thinnet, still at 10Mbps but using thinner coax and
possibly shorter segments, and simpler connectors.

10Base2 and 185m [1] if I remember correctly and the 5-4-3 rules
applies. I used made up (not crimp) BNC connectors and never had a
problem with them.

Heh, your user weren't smart-alec physicists then. Who though that it
looked silly to have the BNC connector connect to the back of the
computer. So they disconnected that, and put some metres of 10base2
cable between the BNC T and the computer. Not realising that this
messed up the cable impedance.

They also decided that the 185m segment was too short, so they extended
it with 50m or so of very thin 50 ohm coax of the type they used in
their own equipment. Not realising that this messed up the DC
resistance of the segment, thus destroying collision detection for
equipment on that segment.

Because of the shape of the building I had an 8 Port multiport
repeater with one port going to my room and 10 'servers / gateways'
and each of the other ports radiating around the building, typically
to different business zones (like 'Sales' or 'Admin').

Much better is twisted pair at 100 and 1000 Mbps, of course, simpler
connectors, much more reliable, no more worrying about bend radius of
your cabling,

Not sure about that?
or the reliability of the taps on your backbone.

Again, I used proper taps, not the 'vampire' type. ;-)

Well on 10base5, vampire taps were all there were. On 10base2, it was
all BNC connectors.

What's helped even more is the reduction in the size of the
electronics, and cost. One connection of a PC to ethernet when I was
first doing it required a whole card slot inside the PC,

'Network cards' are still in common use. ;-)

Can't imagine why. The whole thing is probably one chip or part of one
these days. Why wouldn't it be on the mobo?

Often it is, but if you want more than one Ethernet, you need an extra,
and in some casses you want a particular sort of car when building servers.

Same as video. Most mobos have onboard video, which is OK for basics,
but gamers add their own to get better performance.


--
Future generations will wonder in bemused amazement that the early
twenty-first centurys developed world went into hysterical panic over a
globally average temperature increase of a few tenths of a degree, and,
on the basis of gross exaggerations of highly uncertain computer
projections combined into implausible chains of inference, proceeded to
contemplate a rollback of the industrial age.

Richard Lindzen

On Sun, 22 May 2016 15:47:22 +0100, Tim Streater
wrote:

snip

10Base5 / RG8?

What's RG8?

The thicker version of RG58 (still 50 ohm but lower loss). It's what I
use between my A.R. kit and the triband antenna on the roof.

Then there was thinnet, still at 10Mbps but using thinner coax and
possibly shorter segments, and simpler connectors.

10Base2 and 185m [1] if I remember correctly and the 5-4-3 rules
applies. I used made up (not crimp) BNC connectors and never had a
problem with them.

Heh, your user weren't smart-alec physicists then. Who though that it
looked silly to have the BNC connector connect to the back of the
computer. So they disconnected that, and put some metres of 10base2
cable between the BNC T and the computer. Not realising that this
messed up the cable impedance.

Yup, had a smart arse marketing manager do just that. *Luckily*, the
multiport repeater just isolated that segment so he only affected his
own department. ;-)

They also decided that the 185m segment was too short, so they extended
it with 50m or so of very thin 50 ohm coax of the type they used in
their own equipment. Not realising that this messed up the DC
resistance of the segment, thus destroying collision detection for
equipment on that segment.

Quite.

Because of the shape of the building I had an 8 Port multiport
repeater with one port going to my room and 10 'servers / gateways'
and each of the other ports radiating around the building, typically
to different business zones (like 'Sales' or 'Admin').

Much better is twisted pair at 100 and 1000 Mbps, of course, simpler
connectors, much more reliable, no more worrying about bend radius of
your cabling,

Not sure about that?

or the reliability of the taps on your backbone.

Again, I used proper taps, not the 'vampire' type. ;-)

Well on 10base5, vampire taps were all there were.

Nope. If you were doing it fully you fitted TNC connectors to the ends
of the RG8 and used Transceivers with TNC connectors. ;-)

On 10base2, it was
all BNC connectors.

Agreed.

What's helped even more is the reduction in the size of the
electronics, and cost. One connection of a PC to ethernet when I was
first doing it required a whole card slot inside the PC,

'Network cards' are still in common use. ;-)

Can't imagine why. The whole thing is probably one chip or part of one
these days. Why wouldn't it be on the mobo?

It might be a 'better' card (Gb over 10/100), Wireless, multiport or
higher performance for example. Or you might use one to simply
replace a faulty Ethernet port (physically or logically).

In the case of the training centre I was working at, they ordered
(from Dell) 120 *identical* PC to use thought the centre. They had to
be identical because we (the instructors) built images of the machines
that were then burnt to CD's and so each room could be re-imaged for
whatever course was on in that room the next week by just sticking the
right CD in the machine and rebooting it. [1]

However, whilst the first batch of PC's were identical, the second
batch were different (from the first) and came with different
networking built onto the Mobo. So, we had to disable the onboard LAN
option and Dell supplied us with 20 PCI network cards that used the
same chipset as the others so the OS images worked across all
machines.

I had to cover 'Networking' on the Novell 'Service and Support' course
so I had the delegates physically playing with Arcnet, Token Ring and
(thin) Ethernet and we had 'Show and tell' and theory for a few more.

Cheers, T i m

[1] We did try downloading the images over the LAN using NetBoot but
the load of 120 machines all streaming (different) images at once was
just too slow. We also kept some rooms off the backbone because it
made some courses more complicated and the lunchtime multiplayer FPS
games got too big. ;-)

On Sun, 22 May 2016 14:12:52 +0100, John Rumm wrote:

On 22/05/2016 10:40, The Natural Philosopher wrote:
On 22/05/16 10:13, AnthonyL wrote:

Well that's pretty well how I ended up with the Cisco. For some
reason the customer I had supplied with hardware and software for
years bought the managed switch for his small network. He couldn't
get it to work with the Novell server so I got involved. Once I
showed him a simple switch would do the job fine he got one from me
and gave me the Cisco which for interest I quite easily configured for
our near identical Novell network. But I've never found a use for a
managed switch also preferring KISS so it's barely ever been used.




I've never seen a managed switch under a sort of thousand up machine
network

I have one on my home network... its quite handy for dropping a not to
subtle hint to the sprogs that its too late to be playing minecraft or
streaming films etc ;-)

I have four! Sounds bad but...

I need 24 ports to handle what I have in the house. I went for two 24
port switches rather than a 48 port one because:
- if one fails at lesat I have a fallback for important ports
- the 48 port one has a fan and will be noisier

Then I discovered I didn't have enough ports in the workshop...so I got
an 8 port one. Used up all the ports. Got another 8 port one.

They are all HP 18{1,2}0 models - they were a good price at the time.

Indeed - quite handy for situations in even small offices where you have
two unconnected businesses sharing resources or internet connections,
but you want some isolation between them.

I have a little bit of that, and it's handy for security.



--
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wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
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On Sun, 22 May 2016 15:47:22 +0100, Tim Streater wrote:

'Network cards' are still in common use. ;-)

Can't imagine why. The whole thing is probably one chip or part of one
these days. Why wouldn't it be on the mobo?

When you want an extra one...!



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 22/05/2016 21:41, Bob Eager wrote:
On Sun, 22 May 2016 15:47:22 +0100, Tim Streater wrote:

'Network cards' are still in common use. ;-)

Can't imagine why. The whole thing is probably one chip or part of one
these days. Why wouldn't it be on the mobo?

When you want an extra one...!



Just been dealing with two machines which simply do not work with one
particular function. Different models of Dell. Different companies. Same
failure.

Needed to add a different network card to sort it.

--
Rod

On 21/05/2016 20:51, Rod Speed wrote:


"Michael Chare" wrote in message
...
On 21/05/2016 07:27, News wrote:

Regulars may recall that I ran CAT 5 cable direct from modem to son's
room, to give him the full benefit of our high speed connection. The
cable in his room terminates in a single wall socket.

Now, he wants multiple sockets, to add Xbox etc. Would the simplest
solution be to spend a tenner or so on a switch? I've never used a
switch. Wiring is simply a CAT5 cable from the wall socket to the
switch then similar cables from the switch to PC, Xbox etc? Any
complicated set up or plug and play?

Looking at a D-Link DES-105/B 5 Port 10/100 Metal Housing Desktop Switch
from Amazon, or possibly a cheaper option such as Edimax 5 port 10/100
Switch at less than a fiver from eBuyer.

A cheap solution is to use an old router. Just switch off the DHCP and
make sure that the IP address does not conflict with the settings in
your main router. I have one like that, and I also use it as a second
WiFi access point with the same SSID and password as my main router
but a different channel. I use 1 and 11.

Lot simpler to just buy a basic switch. They don’t cost
enough to matter and are a lot simpler to setup.

And cheaper to run? ISTR 20W/hr, whereas a basic switch 3W/hr? Get your
money back in 6 months . . .

--
Cheers, Rob

T i m wrote:

On Sun, 22 May 2016 14:07:42 +0100, Tim Streater
wrote:

Then there was thinnet, still at 10Mbps but using thinner coax and
possibly shorter segments, and simpler connectors.

10Base2 and 185m [1] if I remember correctly and the 5-4-3 rules
applies. I used made up (not crimp) BNC connectors and never had a
problem with them.

We had an office network which kept having intermittent cable
faults which brought everybody's work to a stop. The IT
department gave us no support at all, and our most sophisticated
piece of fault-finding equipment was a GBP5 multi-meter from
somebody's car boot.

I badgered IT to get some proper kit, but no joy.

Eventually I wrote a proposal for our department to buy a GBP1000
hand-held tester, showing that it would pay back its cost in the
first 15 minutes of network inactivity.

Money well spent, and fault easily found and cured.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On 22/05/2016 14:07, Tim Streater wrote:


Much better is twisted pair at 100 and 1000 Mbps, of course, simpler
connectors, much more reliable, no more worrying about bend radius of
your cabling, or the reliability of the taps on your backbone.

Don't tie knots in your cable or you will find that bend radius matters
especially at 1G.

On 22/05/2016 15:47, Tim Streater wrote:
In article , T i m
wrote:

On Sun, 22 May 2016 14:07:42 +0100, Tim Streater
wrote:

In article , Andrew Gabriel
wrote:

In article ,
News writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com
hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s.
ICBR, but I think hubs had vanished before 100Mbit ethernet became
popular
(possibly because they can't convert speeds to perform interworking).

We have to watch the terminology. When I started with Ethernet (1983),
you used yellow coax as the backbone, at 10Mbps.

10Base5 / RG8?

What's RG8?

I remember ordering 5km of cable for ethernet from a UK company.
It was the minimum I could get so they would tool up to make it.
It happened to be for the first ethernet installed in a GEC company and
everyone said it wouldn't work.

I only needed 1km of it but the IT department soon used the rest up once
they discovered distributed terminal servers to connect to the Unix boxes.


The vampires were expensive at about £400 a throw.


Then there was thinnet, still at 10Mbps but using thinner coax and
possibly shorter segments, and simpler connectors.

10Base2 and 185m [1] if I remember correctly and the 5-4-3 rules
applies. I used made up (not crimp) BNC connectors and never had a
problem with them.

Heh, your user weren't smart-alec physicists then. Who though that it
looked silly to have the BNC connector connect to the back of the
computer. So they disconnected that, and put some metres of 10base2
cable between the BNC T and the computer. Not realising that this
messed up the cable impedance.

They also decided that the 185m segment was too short, so they extended
it with 50m or so of very thin 50 ohm coax of the type they used in
their own equipment. Not realising that this messed up the DC
resistance of the segment, thus destroying collision detection for
equipment on that segment.

It was much worse than that.
You could get machines that could see others but not all the machines on
the segment.
Really difficult to explain it to some users.

On 22/05/2016 15:47, Tim Streater wrote:

Well on 10base5, vampire taps were all there were.

Intel did a box with several ports on it that looked like a group of
vampires. It had one port to connect to a vampire. I had a few of these
boxes to connect stuff to.

On Mon, 23 May 2016 05:59:46 +0100, RJH wrote:

Lot simpler to just buy a basic switch. They dont cost enough to
matter and are a lot simpler to setup.

And cheaper to run? ISTR 20W/hr, whereas a basic switch 3W/hr? Get your
money back in 6 months . . .

I think you mean 20W, or 3W. Forget the /hr.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 23/05/16 11:11, Tim Streater wrote:
In article . com,
dennis@home wrote:

On 22/05/2016 15:47, Tim Streater wrote:

Heh, your user weren't smart-alec physicists then. Who though that it
looked silly to have the BNC connector connect to the back of the
computer. So they disconnected that, and put some metres of 10base2
cable between the BNC T and the computer. Not realising that this
messed up the cable impedance.

They also decided that the 185m segment was too short, so they extended
it with 50m or so of very thin 50 ohm coax of the type they used in
their own equipment. Not realising that this messed up the DC
resistance of the segment, thus destroying collision detection for
equipment on that segment.

It was much worse than that. You could get machines that could see
others but not all the machines on the segment. Really difficult to
explain it to some users.

Yes, that too. Original ethernet was a bit suck-it-and-see. The
original designers were very firm about obeying the rules. Do that,
they said, and it ought to work. Otherwise it's a bit like a sausage.
Squeeze it here and it pops out there, and you won't know where "there"
is. Luckily the first thing our tech did was inspect the cabling, so it
wasn't hard to find what had been done - we all had a good larf about
it. Scientists, eh?

Oh yes. I remember 'some' pcs not working on the coax when others did.
Unterminated lengths of cable.

Cat5/switches was a total relief...




--
Those who want slavery should have the grace to name it by its proper
name. They must face the full meaning of that which they are advocating
or condoning; the full, exact, specific meaning of collectivism, of its
logical implications, of the principles upon which it is based, and of
the ultimate consequences to which these principles will lead. They must
face it, then decide whether this is what they want or not.

Ayn Rand.

On Mon, 23 May 2016 10:40:04 +0100, dennis@home wrote:

On 22/05/2016 15:47, Tim Streater wrote:

Well on 10base5, vampire taps were all there were.

Intel did a box with several ports on it that looked like a group of
vampires. It had one port to connect to a vampire. I had a few of these
boxes to connect stuff to.

DEC had the DELNI...'Ethernet in a box' in 1983...

https://en.wikipedia.org/wiki/Digita...k_Interconnect




--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

Bob Eager wrote:

DEC had the DELNI...'Ethernet in a box' in 1983...

https://en.wikipedia.org/wiki/Digita...k_Interconnect

With more thinwire devices than those using MAUs and drop cables we had
a DEMPR.

On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
News writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com hub,
which I tried. It worked, but killed the speed.

Probably only 10Mbits/s.
ICBR, but I think hubs had vanished before 100Mbit ethernet became
popular (possibly because they can't convert speeds to perform
interworking).


The only reason I ever kept a hub was I had some old ethernet 10Base2
cabling to an old server and the hub had a BNC connector. I could then
connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

--
Johnny B Good

On 23/05/2016 12:36, Bob Eager wrote:
On Mon, 23 May 2016 10:40:04 +0100, dennis@home wrote:

On 22/05/2016 15:47, Tim Streater wrote:

Well on 10base5, vampire taps were all there were.

Intel did a box with several ports on it that looked like a group of
vampires. It had one port to connect to a vampire. I had a few of these
boxes to connect stuff to.

DEC had the DELNI...'Ethernet in a box' in 1983...

https://en.wikipedia.org/wiki/Digita...k_Interconnect

The intel system was similar to of these but was an earlier version and
came with a box with five ports IIRC.

https://books.google.co.uk/books?id=...%20nds&f=false

I got the first one in Europe and it transformed the MDS systems.
It was actually faster than having the hard drive connected to the MDS
and it cost less.

On 23/05/16 16:55, Johnny B Good wrote:
On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
News writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com hub,
which I tried. It worked, but killed the speed.

Probably only 10Mbits/s.
ICBR, but I think hubs had vanished before 100Mbit ethernet became
popular (possibly because they can't convert speeds to perform
interworking).


The only reason I ever kept a hub was I had some old ethernet 10Base2
cabling to an old server and the hub had a BNC connector. I could then
connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

Chuck em for scrap. even the cable at 50 ohms is no good for TV/VHF radio.



--
"Women actually are capable of being far more than the feminists will let
them."

On 23/05/2016 11:03, Tim Streater wrote:
In article , Chris J Dixon
wrote:

T i m wrote:

On Sun, 22 May 2016 14:07:42 +0100, Tim Streater
wrote:

Then there was thinnet, still at 10Mbps but using thinner coax and
possibly shorter segments, and simpler connectors.

10Base2 and 185m [1] if I remember correctly and the 5-4-3 rules
applies. I used made up (not crimp) BNC connectors and never had a
problem with them.

We had an office network which kept having intermittent cable
faults which brought everybody's work to a stop. The IT
department gave us no support at all, and our most sophisticated
piece of fault-finding equipment was a GBP5 multi-meter from
somebody's car boot.

I badgered IT to get some proper kit, but no joy.

Eventually I wrote a proposal for our department to buy a GBP1000
hand-held tester, showing that it would pay back its cost in the
first 15 minutes of network inactivity.

Money well spent, and fault easily found and cured.

Luckily our lot had a TDR, so when it was easy to find the short caused
when raccoons or something chewed the ethernet cable almost through.
"Lift that slab", said our man and sure enough ...


In theory most ethernet chips had a TDR function built in, however
finding software that could use it was hard.

On Sat, 21 May 2016 15:17:59 +0100, newshound wrote:

On 5/21/2016 2:59 PM, Graham. wrote:
On Sat, 21 May 2016 10:34:48 +0100, News
wrote:

In message , Bob Minchin
writes
News wrote:

OK, thanks to you both (Mike and Andy). Point taken, and D-Link
5-Port Gigabit Switch ordered through ebuyer, partly because, having
read the comments and reviews in another thread, I could not resist
the Xenta 163 Piece Rotary Tool and Accessory Kit.
When you set it up, you need to turn off DHCP in the new switch so
that your current modem/switch still remains in charge of allocating
IP addresses.

Noted, thanks, although I feel a further question may be necessary,
when it arrives :-)

Feel free, but they are pretty foolproof these days (That sounds more
polite than idiot proof).

15 years ago you would have uplink ports, and crossover cables to
contend with, but now that's all taken care of.

Best one was the Sweex router I bought when I first got broadband, I
nearly took it back as faulty, then I discovered that all four switch
ports worked fine with a NIC when a crossover cable was used, and a
straight cable was needed to connect to a second switch. I've still got
it somewhere.



Once in a while (months?) you might find things stop working, just
switch off and then on again.

Not a Netgear GS608 by any chance? :-)

That's certainly been my experience with that particular GBit switch
over the years. The symptoms being rather oddball problems effecting wan
rather than lan connections (i.e. internet connections).

My first attempts at resetting the 'Usual Suspect' failed to fix the
issue due to my neglecting to include the GS608 in the "Reset Program".
Once I realised that resetting the switch, rather than the router/cable
modem was all that was needed in almost every subsequent case of
'networking issues', restarting or even power cycling the VM Superhub2
became the very last resort.

Prior to the speed upgrade that had precipitated the replacement of the
Ambit cable modem with a Superhub2 cable modem router with Gbit lan
ports, I'd been using my own seperate routers which were all in need of
resetting from time to time (weeks to several months depending on the
make and model used) whilst the fast ethernet switches (a maximum of two
at my QTH) never ever needed a reset.

The change of "Usual Suspect" from router to Gbit switch was a novel
experience for me at that time. I've just assumed it was simply something
peculiar to my particular example of a GS608 Netgear switch. Has anyone
else seen similar problems with other makes/models of ethernet switch?

--
Johnny B Good

In article ,
The Natural Philosopher wrote:
On 23/05/16 16:55, Johnny B Good wrote:
On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
News writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com
hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s.
ICBR, but I think hubs had vanished before 100Mbit ethernet became
popular (possibly because they can't convert speeds to perform
interworking).


The only reason I ever kept a hub was I had some old ethernet 10Base2
cabling to an old server and the hub had a BNC connector. I could then
connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

Chuck em for scrap. even the cable at 50 ohms is no good for TV/VHF radio.

really?

--
from KT24 in Surrey, England

On 23/05/16 17:56, charles wrote:
In article ,
The Natural Philosopher wrote:
On 23/05/16 16:55, Johnny B Good wrote:
On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
News writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com
hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s.
ICBR, but I think hubs had vanished before 100Mbit ethernet became
popular (possibly because they can't convert speeds to perform
interworking).


The only reason I ever kept a hub was I had some old ethernet 10Base2
cabling to an old server and the hub had a BNC connector. I could then
connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

Chuck em for scrap. even the cable at 50 ohms is no good for TV/VHF radio.

really?

Well not for an antenna anyway.

Most RF work is done at 75ohms or 300 ohms for reasons to do with the
permittivity of free space or summat. Mr Sayer might know more

50 ohms is very much the 'lab standard for RF/video kit that never gets
to see an aerial'..

I.e. one tended to come into the first stage RF preamp via 75 ohm using
belling lee or other suitable 75 ohm connector, terminate with 75 ohm,
then amplify and spit it out to the next bit of kit at 50 ohms/BNC.

People doing clever RF in the lab might take some of them.



--
All political activity makes complete sense once the proposition that
all government is basically a self-legalising protection racket, is
fully understood.

In article , The Natural Philosopher
wrote:
On 23/05/16 17:56, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 16:55, Johnny B Good wrote:
On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article , News
writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com
hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s. ICBR, but I think hubs had vanished before
100Mbit ethernet became popular (possibly because they can't
convert speeds to perform interworking).


The only reason I ever kept a hub was I had some old ethernet
10Base2 cabling to an old server and the hub had a BNC connector. I
could then connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

Chuck em for scrap. even the cable at 50 ohms is no good for TV/VHF
radio.

really?

Well not for an antenna anyway.

Most RF work is done at 75ohms or 300 ohms for reasons to do with the
permittivity of free space or summat. Mr Sayer might know more

50 ohms is very much the 'lab standard for RF/video kit that never gets
to see an aerial'..

a great many professional aerials (or should I say antennae?) are of 50ohm
impedance.

--
from KT24 in Surrey, England

On 23/05/16 18:24, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 17:56, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 16:55, Johnny B Good wrote:
On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article , News
writes:
Strange that Andrew mentioned hubs, up there ^. I do have a 3com
hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s. ICBR, but I think hubs had vanished before
100Mbit ethernet became popular (possibly because they can't
convert speeds to perform interworking).


The only reason I ever kept a hub was I had some old ethernet
10Base2 cabling to an old server and the hub had a BNC connector. I
could then connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

Chuck em for scrap. even the cable at 50 ohms is no good for TV/VHF
radio.

really?

Well not for an antenna anyway.

Most RF work is done at 75ohms or 300 ohms for reasons to do with the
permittivity of free space or summat. Mr Sayer might know more

50 ohms is very much the 'lab standard for RF/video kit that never gets
to see an aerial'..

a great many professional aerials (or should I say antennae?) are of 50ohm
impedance.

Unlikely. Not at the raw antenna level. You HAVE to match using some
kind of extra circuitry for any other impedance than 75 ohm (quarter
wave) or 300 ohm (half wave).


--
"Women actually are capable of being far more than the feminists will let
them."

In article , The Natural Philosopher
wrote:
On 23/05/16 18:24, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 17:56, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 16:55, Johnny B Good wrote:
On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article , News
writes:
Strange that Andrew mentioned hubs, up there ^. I do have a
3com hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s. ICBR, but I think hubs had vanished
before 100Mbit ethernet became popular (possibly because they
can't convert speeds to perform interworking).


The only reason I ever kept a hub was I had some old ethernet
10Base2 cabling to an old server and the hub had a BNC connector.
I could then connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

Chuck em for scrap. even the cable at 50 ohms is no good for TV/VHF
radio.

really?

Well not for an antenna anyway.

Most RF work is done at 75ohms or 300 ohms for reasons to do with the
permittivity of free space or summat. Mr Sayer might know more

50 ohms is very much the 'lab standard for RF/video kit that never
gets to see an aerial'..

a great many professional aerials (or should I say antennae?) are of
50ohm impedance.

Unlikely. Not at the raw antenna level. You HAVE to match using some
kind of extra circuitry for any other impedance than 75 ohm (quarter
wave) or 300 ohm (half wave).

Ground plane antenna?

--
from KT24 in Surrey, England

On Monday, 23 May 2016 18:30:41 UTC+1, The Natural Philosopher wrote:

a great many professional aerials (or should I say antennae?) are of 50ohm
impedance.

Unlikely. Not at the raw antenna level. You HAVE to match using some
kind of extra circuitry for any other impedance than 75 ohm (quarter
wave) or 300 ohm (half wave).

Quarter-wave monopoles can be made to give an excellent match to 50 ohms
without needing any extra matching components.

John

On Sat, 21 May 2016 10:33:11 +0100, Tim Watts wrote:

On 21/05/16 07:27, News wrote:

Regulars may recall that I ran CAT 5 cable direct from modem to son's
room, to give him the full benefit of our high speed connection. The
cable in his room terminates in a single wall socket.

Now, he wants multiple sockets, to add Xbox etc. Would the simplest
solution be to spend a tenner or so on a switch? I've never used a
switch. Wiring is simply a CAT5 cable from the wall socket to the
switch then similar cables from the switch to PC, Xbox etc? Any
complicated set up or plug and play?

Looking at a D-Link DES-105/B 5 Port 10/100 Metal Housing Desktop
Switch from Amazon, or possibly a cheaper option such as Edimax 5 port
10/100 Switch at less than a fiver from eBuyer.

Thanks!

My advice is don't be cheap - use gig switches (You said Cat5 - I
assumed you mean Cat5e?). 100Mbit might be enough for your internet
throughput, but if you later add a media server on one part of the house
or want to shift files between your computer and his?

But yes, it is an excellent idea.

Netgear GS series switches are reliable:

Assuming my experience with the GS608 is typical and you include it
amongst the "Usual Suspects" list of "Things that need to be reset" when
things go weird with the network, it works very well for weeks/months at
a time. :-)


http://www.currys.co.uk/gbuk/computi...rking/network-
routers-and-switches/network-switches/netgear-gs108-prosafe-8-port-
ethernet-switch-00939526-pdt.html

£35 ish.

For a simple home network, they need no configuration and there is no
problem with mixing models and brands.

Yes, "modern"[1] unmanaged ethernet switches are about as "Plug 'n'
Play" as it gets. As someone else in this thread pointed out, it's about
as easy as using mains lead extensions (but without the overloading/fire
and electrocution hazards).

These days there's no compelling case for specifying Fast over Gbit
ethernet switches on cost grounds, especially as entry level Desktop PCs
and proper Notebooks have been equipped with Gbit lan ports as standard
fit for the past 5 years or more. This is true even if you still have
older kit or "Novelty Gadgets" (games consoles, mobile phones, tablets
etc) with nothing faster than a fast ethernet port to connect up to your
lan.

Unlike the bad old days of ethernet hub technology when connecting a
10Mbps gadget would slow the whole of a fast ethernet lan down to just
that speed, a modern Fast or Gbit ethernet switch allows all kit to
communicate at their own speed limit.

A link via a Gbps switch between a 100Mbps device and a Gbps device will
limit the data flow rate to that of the slowest whilst still allowing the
Gbps device to exchange data with yet another Gbps device at close to 90%
of the Gbps speed limit. Indeed, data transfers in an 8 port Gbit switch
could go at full speed between all 4 pairs of connected computers
simultaneously depending on the switch's total "packet store and forward"
performance capability.

A quick perusal of the specs[2] for the GS608 suggests two independent
links (two pairs of computers) can go at full speed before a third link
will start to slow things down.


[1] And by "modern", I mean anything designed during the past 15 years or
so (essentially any such kit that *isn't* an ethernet hub).

[2] It speaks volumes for how far the internet (and networking kit) has
evolved when, contrary to the experience of 15 years ago (post dial-up,
128Kbps always-on cable broadband), it would have been quicker to walk
across the hall to the next room, from which to retrieve the packaging to
let you extract the user guide from, just to check such specs than it
would be to google "GS608 specs" and click the second hit to instantly
download the same user guide as a pdf file as I did just now simply on
account ICBA to walk across the hallway. :-)

--
Johnny B Good

On 23/05/16 18:48, wrote:
On Monday, 23 May 2016 18:30:41 UTC+1, The Natural Philosopher wrote:

a great many professional aerials (or should I say antennae?) are of 50ohm
impedance.

Unlikely. Not at the raw antenna level. You HAVE to match using some
kind of extra circuitry for any other impedance than 75 ohm (quarter
wave) or 300 ohm (half wave).

Quarter-wave monopoles can be made to give an excellent match to 50 ohms
without needing any extra matching components.


You may think there are no (extra components) , but there are.

Even if they look like twisted bits of wire..


John




--
"When one man dies it's a tragedy. When thousands die it's statistics."

Josef Stalin

On 23/05/16 18:43, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 18:24, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 17:56, charles wrote:
In article , The Natural Philosopher
wrote:
On 23/05/16 16:55, Johnny B Good wrote:
On Sun, 22 May 2016 09:18:43 +0000, AnthonyL wrote:

On Sun, 22 May 2016 08:27:50 -0000 (UTC),
(Andrew Gabriel) wrote:

In article , News
writes:
Strange that Andrew mentioned hubs, up there ^. I do have a
3com hub, which I tried. It worked, but killed the speed.

Probably only 10Mbits/s. ICBR, but I think hubs had vanished
before 100Mbit ethernet became popular (possibly because they
can't convert speeds to perform interworking).


The only reason I ever kept a hub was I had some old ethernet
10Base2 cabling to an old server and the hub had a BNC connector.
I could then connect the hub to a switch to join the whole network.

Now - what do I do with loads of 10Base2 cable and connectors?

Keep them in a large poly bag in the bottom drawer of a filing
cabinet... for at least a decade? :-)

Chuck em for scrap. even the cable at 50 ohms is no good for TV/VHF
radio.

really?

Well not for an antenna anyway.

Most RF work is done at 75ohms or 300 ohms for reasons to do with the
permittivity of free space or summat. Mr Sayer might know more

50 ohms is very much the 'lab standard for RF/video kit that never
gets to see an aerial'..

a great many professional aerials (or should I say antennae?) are of
50ohm impedance.

Unlikely. Not at the raw antenna level. You HAVE to match using some
kind of extra circuitry for any other impedance than 75 ohm (quarter
wave) or 300 ohm (half wave).

Ground plane antenna?

Generally half a 75 ohm - 36 ohm,

See...

http://electronicdesign.com/wireless...-plane-antenna.

You MIGHT use 50 ohms for that, but it will suffer from some reflections.


--
"When one man dies it's a tragedy. When thousands die it's statistics."

Josef Stalin

On Mon, 23 May 2016 09:40:48 +0000, Bob Eager wrote:

On Mon, 23 May 2016 05:59:46 +0100, RJH wrote:

Lot simpler to just buy a basic switch. They dont cost enough to
matter and are a lot simpler to setup.

And cheaper to run? ISTR 20W/hr, whereas a basic switch 3W/hr? Get your
money back in 6 months . . .

I think you mean 20W, or 3W. Forget the /hr.

Exactly right! Saved me the need to point that out (although I just
did). However, my point was that it's more like a maximum of 12 watts for
a Superhub2 cable modem/wifi router with 4 port Gbit switch built in and
something like 6 to 7 watts (rather than the 12 watts claimed in the user
guide) for a GS608 ethernet switch.

Also, it's worth pointing out that such networking kit can be powered
from any wallwart supplying anywhere from 6 to 15 volts DC that has a VA
rating in excess of the minimum *actually* demanded by said kit.

The reason being that any such kit less than 15 years old will be using
switching regulator technology[1] to 'condition' or regulate the wallwart
output voltage ranging from as low as 5.0v at the extreme low end,
through to 15v (or even 25v- depends on the voltage rating of the input
filter capacitor) down to the 5v level typically used by the circuitry
inside.

Supplying 6 volts to a 12vdc 6W rated ethernet switch will result in a
1A draw versus half amp at 12v - about the same wattage. This can be
handy when replacing, for a real life example, an original 7.5vac 1A
lossy and bulky transformer wallwart[2] with a more compact, lightweight
and much more efficient 12vdc 1A rated smpsu based wallwart (the internal
bridge rectifier inside the router or cable modem or why will simply pass
the DC through, albeit with around a 1.5v drop).

[1] We owe thanks for this improvement in regulator technology to, rather
surprisingly, "The Bean Counters". Whilst 'sophisticated' switching
regulator technology was initially an expensive solution compared to good
old fashioned analogue voltage regulation techniques, this was soon to
change.

The desire to save manufacturing costs by replacing expensive metal
casings with cheap injection moulded plastics meant the problem of
removing the waste heat generated by an analogue voltage regulator became
an unaffordable luxury. The, at the time, more expensive switching
regulator option could afford the designers a considerable BoM and
shipping savings which easily outweighed the 'extra cost' of a switching
regulator and once demand for switching regulator chips was boosted to
mass production levels, the 'Analogue Solution' then became the
'expensive option'.

The use of plastic for the case is a guarantee that what is inside
relies on a switching regulator which has a very catholic taste in
voltage requirements, certainly far less fussy than the voltage marking
by the power input socket would imply.

In my experience, all dc output wallwarts put their positive output on
the centre pin of the co-axial plug. The only obstacle to using an
alternative wallwart will be the plug/socket dimensions requiring either
a converter lead or simply using the plug from the old wallwart to
replace the one on the new.

There are various solutions for achieving this, ranging from a
reversible 'bodge' to permanent neatness depending on your dis/assembly
skills of ultrasonically welded plastic parts and soldering skills.
Sometimes, however, the donor wallwart's plug happens to be a close
enough match to fit well enough to function reliably. It's one of the
main reasons for keeping a few dozen 'flea market' purchased examples in
a box for just such purposes. :-)


[2] WARNING! Do *not* attempt to use a low voltage AC output wallwart as
a substitute for a low voltage DC output wallwart. Using a DC output
wallwart in place of a simple wallwart transformer that provides a low
voltage 50/60Hz ac output is generally ok. The only exception to this
rule ime, was with some of the *really* ancient external dial-up modems
which relied on the ac to produce the negative 5 or 12 volt rail for the
RS232 line driver chips which drove the serial port interface.

--
Johnny B Good

On 23/05/2016 22:27, Johnny B Good wrote:
On Mon, 23 May 2016 09:40:48 +0000, Bob Eager wrote:

On Mon, 23 May 2016 05:59:46 +0100, RJH wrote:

Lot simpler to just buy a basic switch. They dont cost enough to
matter and are a lot simpler to setup.

And cheaper to run? ISTR 20W/hr, whereas a basic switch 3W/hr? Get your
money back in 6 months . . .

I think you mean 20W, or 3W. Forget the /hr.

Exactly right! Saved me the need to point that out (although I just
did). However, my point was that it's more like a maximum of 12 watts for
a Superhub2 cable modem/wifi router with 4 port Gbit switch built in and
something like 6 to 7 watts (rather than the 12 watts claimed in the user
guide) for a GS608 ethernet switch.


Ah, many thanks (and Tim and Bob), often get confused with the method of
expressing power consumption!

Just FYI, my 5 port Zyxel switch measures at 1.5-2W, and my router (BT
Homehub 5) 10-15W. So for me it'd take almost a year to get my money
back - nothing like the 6 months I suggested, and way off your more
accurate representative example.

I do of course defer to your measurements - I was just working from my
(poor) memory.


--
Cheers, Rob

On Monday, 23 May 2016 22:17:12 UTC+1, The Natural Philosopher wrote:

http://electronicdesign.com/wireless...-plane-antenna.

You MIGHT use 50 ohms for that, but it will suffer from some reflections.

A useful reference is:
Antenna theory analysis and design by Balanis. About 1000 pages long.

On Monday, 23 May 2016 22:12:31 UTC+1, The Natural Philosopher wrote:
On 23/05/16 18:48, wrote:
On Monday, 23 May 2016 18:30:41 UTC+1, The Natural Philosopher wrote:

a great many professional aerials (or should I say antennae?) are of 50ohm
impedance.

Unlikely. Not at the raw antenna level. You HAVE to match using some
kind of extra circuitry for any other impedance than 75 ohm (quarter
wave) or 300 ohm (half wave).

Quarter-wave monopoles can be made to give an excellent match to 50 ohms
without needing any extra matching components.


You may think there are no (extra components) , but there are.

Even if they look like twisted bits of wire..

There is no need for any twisted bits of wire to make a quarter-wave monopole with a 50 ohm impedance at resonance.

John

On 24/05/16 08:34, wrote:
On Monday, 23 May 2016 22:12:31 UTC+1, The Natural Philosopher wrote:
On 23/05/16 18:48, wrote:
On Monday, 23 May 2016 18:30:41 UTC+1, The Natural Philosopher wrote:

a great many professional aerials (or should I say antennae?) are of 50ohm
impedance.

Unlikely. Not at the raw antenna level. You HAVE to match using some
kind of extra circuitry for any other impedance than 75 ohm (quarter
wave) or 300 ohm (half wave).

Quarter-wave monopoles can be made to give an excellent match to 50 ohms
without needing any extra matching components.


You may think there are no (extra components) , but there are.

Even if they look like twisted bits of wire..

There is no need for any twisted bits of wire to make a quarter-wave monopole with a 50 ohm impedance at resonance.

A quarter wave monopole is always 36 ohms. End of discussion

"Since a half-wave dipole has a gain of 2.19 dBi and a radiation
resistance of 73 ohms, a quarter-wave monopole, the most common type,
will have a gain of 2.19 + 3 = 5.19 dBi and a radiation resistance of
about 36.8 ohms if it is mounted above a good ground plane.[1]"

https://en.wikipedia.org/wiki/Monopole_antenna

John



--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

On Tuesday, 24 May 2016 10:14:58 UTC+1, The Natural Philosopher wrote:

A quarter wave monopole is always 36 ohms. End of discussion

As you wish. I'll just carry on doing the impossible then.
(I do have a vector network analyzer for doing the measuremnts.)

John

On 23/05/2016 19:50, Johnny B Good wrote:

[2] It speaks volumes for how far the internet (and networking kit) has
evolved when, contrary to the experience of 15 years ago (post dial-up,
128Kbps always-on cable broadband), it would have been quicker to walk
across the hall to the next room, from which to retrieve the packaging to
let you extract the user guide from, just to check such specs than it
would be to google "GS608 specs" and click the second hit to instantly
download the same user guide as a pdf file as I did just now simply on
account ICBA to walk across the hallway. :-)

You want to try my broadband - sometimes it would be quicker by post!


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"The Natural Philosopher" wrote in message
...
..

A quarter wave monopole is always 36 ohms. End of discussion

"Since a half-wave dipole has a gain of 2.19 dBi and a radiation resistance of 73 ohms,
a quarter-wave monopole, the most common type, will have a gain of 2.19 + 3 = 5.19 dBi
and a radiation resistance of about 36.8 ohms if it is mounted above a good ground
plane.[1]"

https://en.wikipedia.org/wiki/Monopole_antenna

It looks like a 5 year old Turnip must have been at home sick, on the day
the teacher chalked the word "if" on the blackboard.


michael adams

....

On 24/05/16 12:41, maurice wrote:
"The Natural Philosopher" wrote in message
...
..

A quarter wave monopole is always 36 ohms. End of discussion

"Since a half-wave dipole has a gain of 2.19 dBi and a radiation resistance of 73 ohms,
a quarter-wave monopole, the most common type, will have a gain of 2.19 + 3 = 5.19 dBi
and a radiation resistance of about 36.8 ohms if it is mounted above a good ground
plane.[1]"

https://en.wikipedia.org/wiki/Monopole_antenna

It looks like a 5 year old Turnip must have been at home sick, on the day
the teacher chalked the word "if" on the blackboard.


If it isnt, it still wont be 50 ohms

You may still choose to feed it from 50 ohms, and accept a crap VSWR,
but that doesn't make the monopole a '50 ohm impedance antenna'


michael adams

....




--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly

"The Natural Philosopher" wrote in message
...
On 24/05/16 12:41, maurice wrote:
"The Natural Philosopher" wrote in message
...
..

A quarter wave monopole is always 36 ohms. End of discussion

"Since a half-wave dipole has a gain of 2.19 dBi and a radiation resistance of 73
ohms,
a quarter-wave monopole, the most common type, will have a gain of 2.19 + 3 = 5.19
dBi
and a radiation resistance of about 36.8 ohms if it is mounted above a good ground
plane.[1]"

https://en.wikipedia.org/wiki/Monopole_antenna

It looks like a 5 year old Turnip must have been at home sick, on the day
the teacher chalked the word "if" on the blackboard.


If it isnt, it still wont be 50 ohms

It looks as if he was also off sick on the day the teacher chalked up "is always"
and "If it isn't" on the board, and asked the children if both could be true at the
same time.

A very sickly child, by the looks of things.


michael adams

....

On 24/05/16 13:13, maurice wrote:
"The Natural Philosopher" wrote in message
...
On 24/05/16 12:41, maurice wrote:
"The Natural Philosopher" wrote in message
...
..

A quarter wave monopole is always 36 ohms. End of discussion

"Since a half-wave dipole has a gain of 2.19 dBi and a radiation resistance of 73
ohms,
a quarter-wave monopole, the most common type, will have a gain of 2.19 + 3 = 5.19
dBi
and a radiation resistance of about 36.8 ohms if it is mounted above a good ground
plane.[1]"

https://en.wikipedia.org/wiki/Monopole_antenna

It looks like a 5 year old Turnip must have been at home sick, on the day
the teacher chalked the word "if" on the blackboard.


If it isnt, it still wont be 50 ohms

It looks as if he was also off sick on the day the teacher chalked up "is always"
and "If it isn't" on the board, and asked the children if both could be true at the
same time.

A very sickly child, by the looks of things.


michael adams


I assume you are of the Left persuasion, as this all out ad hominem
continues?

You do realise how unpleasant and stupid you are appearing?

....





--
No Apple devices were knowingly used in the preparation of this post.