>>> Part 1 of 2...
 
-=> On 03-19-98  10:07, Ray Wade said to Rob Dennis,<=-
-=>"About Antennas......,"<=-
-=> On (18 Mar 98) Rob Dennis wrote to Holger Granholm...
 
Hi, Ray;
...
 
 RW> Dunno about Canada, but I would suspect that your phones work like
 RW> ours do here in the US.
 
I'm sure they do.
 
 RW> It is true that the phone "cable" (grey colored insulation on the
 RW> outside) that runs inside homes and businesses has four wires.
 
Actually, it comes in three colors on the outside: Gray, Tan and Ivory.
 
 RW> The four wires have insulation on them and are red, green,
 RW> yellow and (I have forgotten the last one, brown perhaps).
 
The fourth conductor is black.  At one time it was used in conjunction
with the yellow wire, (grounded), to supply 8-10 volts AC from a
transformer located in some out-of-the-way place in the house to the
lights in "Princess" phones.  (I used to install phones.)
 
 RW> It only takes one pair of the four to connect a single phone line,
 RW> thus each grey cable will support *two* individual phone "lines".
 
True, but a phone company installer will turn purple of they find it
connected that way... "It just isn't right!"  (But it works fine!)
 
 RW> Maybe 60 or more years ago three of these conductors were used. I
 RW> believe they were the red, green and yellow, with yellow connected to
 RW> "ground", and red and green for the actual "line". The unused
 RW> conductor was a "spare" in case one of the others were damaged
 RW> somehow...
 
Actually, the third wire, (yellow), was grounded, and was used in selective
ringing in 2-party lines: One line rang Green to ground, the other rang red
to ground.  For more than 2-party lines, frequency selective ringers were
used for up to, IIRC, 8 lines, and up to 16 party-lines, (very common in
rural areas for many years), used a combination of frequency-selective
ringers, and red or green to ground. Some rural areas even used ring-1 and
ring-2, (a "split" ring). The single-party lines found almost exclusively
today use "bridged" ringing, which puts 90 VAC at 20 Hz between the red and
green wires, and ground is only used for lightning protection.
...
 
 RW> ... The "ground" wire was attached to a ground
 RW> rod that was driven into the ground outside the house or business.
 
Nowadays they just put a ground clamp on the nearest cold water pipe.
...
 
 RW> Nowdays there is only *one* ground rod and all wiring, including AC
 RW> power, cable TV etc are connected to this single ground rod. This is
 RW> to prevent what is called a "ground loop"...
 
Actually, you can easily get a ground lop with a single ground point!  All
it takes is a complete "circle" of conductors, which can be connected to
Earth ground at any point.  The house wiring acts like the primary of a
transformer, setting up a 60 HZ magnetic field, and the loop acts like the
secondary, and surprisingly large currents can flow!
 
 RW> ... I say this because *my*
 RW> cable TV was installed many years ago (1975 when the house was new) by
 RW> the local cable TV supplier and they put in a second ground rod for the
 RW> cable TV, that entered my house on the end opposite of all other
 RW> utilities ground rod...
 RW> They wanted to trench a new ground connection all the way from one end
 RW> of the house to the other to comply with the new "code"... I
 RW> had to sign a waiver and was told if I took a "lightening" hit that
 RW> came in the house via the cable TV, that they would no longer be
 RW> responsible for any possible damage. So be it.
 
Why in the [CENSORED] couldn't they drive another ground rod where the NEW
service came in and just disconnect the old one, or better yet, just
connect their lightning arrestor to the existing ground for the other
utilities?
 
 RW> BTW, *all* of the grey colored phone "cable" I have seen uses solid
 RW> conductors, not stranded. About 18 gauge wire, I would guess.  And
 RW> each pair of the wires are "twisted" inside the cable.
 
Correct.
 
 RW> Still the old "twisted pair"! Do you know *why* they are twisted?
 
Yes: it is a balanced line!  Don't believe me?  Try grounding one wire!
If you ground one side, it will hum like crazy!  If you ground the other
one the phone will be completely dead!  When my 2nd Ex- and I moved into
an OLD house.  We hadn't been there long when one day the phone went
totally dead.  I went to the lightning protection carbon blocks & fuses,
(I SAID it was an old house!), and connected a phone from one side to
ground.  Nothing.  I connected it to the other side and got a dial tone
with a hum so loud that you could barely hear the dial tone!  But it was
enough to call repair service!  It seems that a squirrel had gnawed through
the old lead-jacket cable half a block away and cut one wire!  (It was
fixed later that day).
 
Now, let's D-R-A-G this back on topic:  Has anyone ever built, or
considered building, a phone patch?  They can come in very handy!  I am
planning to build one that can connect ANY of my 2-ways, (HF, VHF, UHF and
the business-band that I dispatch for), to the phone line for emergencies.
(I am up all night, and monitor several repeters.  In the last 3 months, I
have called 911 3 times, twice for vehicle breakdowns and once for someone
being harassed in their car).
 
73 DE KB9QPM
   Ivy
 
 
 
... Become hot stuff... learn to solder!   ;->
 
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