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A good accessory. When I'm driving I like to set my alarm clock toDave Plowman (News) wrote:
I've not researched it so was only a guess. But I've not noticed quality
radios without a trimmer having inferior MW reception than before.
With the number of stations in the band these days, I find weak signal
performance is rarely the limiting factor. Usually the problem is
selectivity.
This discussion reminds me that my old Mercedes had a momentary contact
built into the power antenna switch that would let you adjust the
antenna length up and down from the dashboard. It was kind of cute but
never seemed to make much difference in reception. (Yet another
example of Germans inventing a problem so that they could solve it, I
think.) The radio itself was an old Blaupunkt and was a magnificent
piece of electronics, though. Vastly overengineered. Automatic
three-stage scan, direct frequency entry, and an alarm clock!
RG-62/u was used for Arcnet networking,Michael A. Terrell wrote:
RG/62, 93 ohm coax. The same as what IBM used for their early
computer networks.
I've got some 93 ohm coax lying around from when I used some to make a
matching section. Never knew what the original application was for it.
Very interesting.
Ahh, I love the smell of LANtastic over RG62A/U and TCNS in theOn Tue, 01 Dec 2009 14:12:18 -0800, David Brodbeck <gull@gull.us
wrote:
Michael A. Terrell wrote:
RG/62, 93 ohm coax. The same as what IBM used for their early
computer networks.
I've got some 93 ohm coax lying around from when I used some to make a
matching section. Never knew what the original application was for it.
Very interesting.
RG-62/u was used for Arcnet networking,
http://en.wikipedia.org/wiki/Arcnet
and IBM 3270 terminal systems:
http://en.wikipedia.org/wiki/3270
You might want to ease up on whatever you're sniffing. Arcnet andOn Tue, 01 Dec 2009 23:15:32 -0800, Jeff Liebermann
jeffl@cruzio.com>wrote:
On Tue, 01 Dec 2009 14:12:18 -0800, David Brodbeck <gull@gull.us
wrote:
Michael A. Terrell wrote:
RG/62, 93 ohm coax. The same as what IBM used for their early
computer networks.
I've got some 93 ohm coax lying around from when I used some to make a
matching section. Never knew what the original application was for it.
Very interesting.
RG-62/u was used for Arcnet networking,
http://en.wikipedia.org/wiki/Arcnet
and IBM 3270 terminal systems:
http://en.wikipedia.org/wiki/3270
Ahh, I love the smell of LANtastic over RG62A/U and TCNS in the
morning.
On Wed, 02 Dec 2009 10:11:04 -0500, Meat Plow <meat@petitmorte.net
wrote:
On Tue, 01 Dec 2009 23:15:32 -0800, Jeff Liebermann
jeffl@cruzio.com>wrote:
On Tue, 01 Dec 2009 14:12:18 -0800, David Brodbeck <gull@gull.us
wrote:
Michael A. Terrell wrote:
RG/62, 93 ohm coax. The same as what IBM used for their early
computer networks.
I've got some 93 ohm coax lying around from when I used some to make a
matching section. Never knew what the original application was for it.
Very interesting.
RG-62/u was used for Arcnet networking,
http://en.wikipedia.org/wiki/Arcnet
and IBM 3270 terminal systems:
http://en.wikipedia.org/wiki/3270
Ahh, I love the smell of LANtastic over RG62A/U and TCNS in the
morning.
You might want to ease up on whatever you're sniffing. Arcnet and
3270 used BNC connectors. What's a TCNS?
My favorite gizmo was the passive hub. Huge amounts of cash for a
mysterious sealed box with 3 or more BNC connectors. I eventually
dissected one and was rather disappointed to find only a few
resistors.
I'm still not certain that AM/FM car antenna coax cable is RG-62/u. I
haven't found a suitable car antenna to compare with the boxes and
boxes of RG-62/u I have left over from ripping out Arcnet systems
(Lantastic) and replacing them RG-58a/u (Ethernet and Novell).
Sigh. I never bothered to look. I just found a stainless car whipWhatever. I heard it from some Delco engineers who designed their
car radios in the '70s, and saw it on plenty of car radio antenna cables
in the '60s & '70s.
Well, let's see. The cable is 4.5ft long.The Delco engineers explanation was that a whip
antenna for AM was used as a voltage probe, and 93 ohm coax had the
lowest loss available.
Well, it could be matched to almost anything. However, the low coaxThat made it easier to match to the tuned RF
input.
They didn't PTFE when Bill Lear invented the first "Motorola" carIt was also cheap cable with a polypropylene tube to hold the
braid and surround the zigzag center conductor. Compare that to a low
loss teflon which can cost several dollars a foot.
Well, much of this thread is over my head now, sort of, but ftr, I wasThey didn't PTFE when Bill Lear invented the first "Motorola" car
radio.
Interesting. For example: Learisms:http://en.wikipedia.org/wiki/Bill_Lear
In the land mobile biz, it was called Rotomola.On Wed, 02 Dec 2009 20:28:15 -0800, Jeff Liebermann <jeffl@cruzio.com
wrote:
They didn't PTFE when Bill Lear invented the first "Motorola" car
radio.
Well, much of this thread is over my head now, sort of, but ftr, I was
40 years old before I realized why it was called "motor-ola"
http://en.wikipedia.org/wiki/Bill_Lear
I have a toolbox full of coax and OTP/UTP tools.On Wed, 02 Dec 2009 10:11:04 -0500, Meat Plow <meat@petitmorte.net
wrote:
On Tue, 01 Dec 2009 23:15:32 -0800, Jeff Liebermann
jeffl@cruzio.com>wrote:
On Tue, 01 Dec 2009 14:12:18 -0800, David Brodbeck <gull@gull.us
wrote:
Michael A. Terrell wrote:
RG/62, 93 ohm coax. The same as what IBM used for their early
computer networks.
I've got some 93 ohm coax lying around from when I used some to make a
matching section. Never knew what the original application was for it.
Very interesting.
RG-62/u was used for Arcnet networking,
http://en.wikipedia.org/wiki/Arcnet
and IBM 3270 terminal systems:
http://en.wikipedia.org/wiki/3270
Ahh, I love the smell of LANtastic over RG62A/U and TCNS in the
morning.
You might want to ease up on whatever you're sniffing. Arcnet and
3270 used BNC connectors.
Thomas Conrad Networking System. We used TC cards for Arcnet in bothWhat's a TCNS?
On Wed, 02 Dec 2009 22:28:14 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
Whatever. I heard it from some Delco engineers who designed their
car radios in the '70s, and saw it on plenty of car radio antenna cables
in the '60s & '70s.
Sigh. I never bothered to look. I just found a stainless car whip
antenna with coax cable attached. The number on the cable is:
5PT3-30C LCN
Google couldn't find anything. Both ends are soldered so I can't
inspect the guts. The OD is 5.0mm, which is at one end of the range
of RG-62a/u jacket diameters of 5.1 to 6.2mm. I would measure the
PF/ft, but my destroyed my LCR meter is busted. It probably is
RG-62/u but I'm still not convinced.
The Delco engineers explanation was that a whip
antenna for AM was used as a voltage probe, and 93 ohm coax had the
lowest loss available.
Well, let's see. The cable is 4.5ft long.
ohms pf/ft pF
RG-62/u 93 13 58.5
RG-59/u 75 17 76.5
RG-58/u 50 30 135.
Yeah, I can see the reason. The input tuning stage would never tune
with that much capacitance.
That made it easier to match to the tuned RF
input.
Well, it could be matched to almost anything. However, the low coax
capacitance would give the trimmer in the radio a much wider tuning
range.
It was also cheap cable with a polypropylene tube to hold the
braid and surround the zigzag center conductor. Compare that to a low
loss teflon which can cost several dollars a foot.
They didn't PTFE when Bill Lear invented the first "Motorola" car
radio.
http://en.wikipedia.org/wiki/Bill_Lear
Also, at 1MHz, the difference in cable losses between various
dielectrics is zilch at 4.5 ft. They could have used aluminum foil
wrapped garden hose, with a coat hanger as center conductor, and
gotten the same cable loss.
Do you happen to have any of the TCNS 100Mbit adapters?On Tue, 01 Dec 2009 23:15:32 -0800, Jeff Liebermann
jeffl@cruzio.com>wrote:
On Tue, 01 Dec 2009 14:12:18 -0800, David Brodbeck <gull@gull.us
wrote:
Michael A. Terrell wrote:
RG/62, 93 ohm coax. The same as what IBM used for their early
computer networks.
I've got some 93 ohm coax lying around from when I used some to make a
matching section. Never knew what the original application was for it.
Very interesting.
RG-62/u was used for Arcnet networking,
http://en.wikipedia.org/wiki/Arcnet
and IBM 3270 terminal systems:
http://en.wikipedia.org/wiki/3270
Ahh, I love the smell of LANtastic over RG62A/U and TCNS in the
morning.
Thomas-Conrad Network -- I am particularly interested inWhat's a TCNS?
Unfortunately, no. Haven't seen one since 2001.Meat Plow wrote:
On Tue, 01 Dec 2009 23:15:32 -0800, Jeff Liebermann
jeffl@cruzio.com>wrote:
On Tue, 01 Dec 2009 14:12:18 -0800, David Brodbeck <gull@gull.us
wrote:
Michael A. Terrell wrote:
RG/62, 93 ohm coax. The same as what IBM used for their early
computer networks.
I've got some 93 ohm coax lying around from when I used some to make a
matching section. Never knew what the original application was for it.
Very interesting.
RG-62/u was used for Arcnet networking,
http://en.wikipedia.org/wiki/Arcnet
and IBM 3270 terminal systems:
http://en.wikipedia.org/wiki/3270
Ahh, I love the smell of LANtastic over RG62A/U and TCNS in the
morning.
Do you happen to have any of the TCNS 100Mbit adapters?
Michael
My grandparents have a Philco console set from the 1930s that has thatIncidentally, many police departments used AM frequencies at the top
of the AM broadcast band for dispatch up to the early 1970's. In Smog
Angeles, listening to the police on a tweaked AM car radio was common.
Yeah, that was my reaction at first, too. Later I found it was actuallyA good accessory. When I'm driving I like to set my alarm clock to
wake me up every 15 minutes.
Yes, but it was one way communications from the police station to theJeff Liebermann wrote:
Incidentally, many police departments used AM frequencies at the top
of the AM broadcast band for dispatch up to the early 1970's. In Smog
Angeles, listening to the police on a tweaked AM car radio was common.
My grandparents have a Philco console set from the 1930s that has that
police band marked on the dial.