From Newsgroup: uk.tech.broadcast

On 2026/9/27 16:56:0, Paul wrote:

On Sat, 9/26/2026 3:10 PM, Frank Slootweg wrote:

J. P. Gilliver <G6JPG@255soft.uk> wrote:

uk.tech.broadcast added, as it seemed appropriate! I'll maybe remove the >>> Windows and Linux ones next time.

Please don't do that, unless it's really *only* UK *and* broadcast
related.

UTB added, as I had no idea so many systems were (still?) in use in NL.
I haven't removed the Windows and Linux 'groups though I think we should ...

On 2026/9/26 11:47:1, Abandoned Trolley wrote:

On 26/09/2026 11:11, Carlos E.R. wrote:

[...]

I had not heard of cable radio. Interesting.

I don't think it was called that.>>

In The Netherlands, it was called 'draadomroep', which roughly
translates to wirebroadcast, so 'wire', not 'cable' and 'broadcast', not
'radio' (because it wasn't).

And it indeed worked like (your snipped) Google's AI Overview said.

[...]

Van der Heem N.V. and related companies - The Hague, Utrecht and Sneek

https://www.vanderheem.info/radiocentrale3.html

Various systems were abandoned after testing or not implemented at all because the costs
of operation were too high. The most well-known methods will be briefly mentioned here.

High frequency wire broadcasting;

the intention was to transmit a high frequency over existing conductors (eg high-current conductors),
which were modulated with a low-frequency signal (music, etc.). The filters and further equipment
required at the central point made this system impractical.

High frequency wire broadcasting using 1 double wire.
With this system, which is used in England,
a special double wire system is stretched along the houses, on which branches can be made. Some
carrier waves are conducted on this double wire, which in turn are modulated with the low-frequency
signal; these voltages must be detected at the connected parties, for which a simple receiver is used.

This system can be very excellent in terms of network construction, but the costs that must be incurred
by the affiliated parties will have to determine whether this system can be applied in the Netherlands.

Low frequency wire broadcasting over 1 double-wire telephone.

A wire broadcasting system is in use in the municipality of The Hague, which to date can be used without
additional cable costs. The basic idea of rCirCithis system is to give greater efficiency to the telephone
double wires of private telephone connections, which are unused for 95% of the day. In the telephone
exchange, the radio program is set at telephone level, which is brought up to loudspeaker strength by
the telephone subscriber via an amplifier. The affiliates have a device that ensures that if a telephone
conversation is called up, the radio program is interrupted, so that the telephone conversation can be
made normally, while there is also a push button with which a step switch in the telephone exchange
can be operated, to which the 4 radio programs are placed. This system will be difficult to fit with
advancing telephone technology, so that after a few years this method will be abandoned in The Hague.

Wire broadcasting over 4 telephone double wires.

A method is in use in the municipality of Rotterdam that uses 4 telephone double wires, from which the
connections for radio subscribers are tapped in parallel. In the telephone exchange, as in the system
discussed under 3, the radio programs are again set at telephone level (max 4 Volts), which are brought
to loudspeaker strength for the connected parties via a program selector (switch) and a small amplifier.
This system has the disadvantage that 4 double wires must be reserved for radio purposes in all branch
telephone cables, while making a connection (underground) is often more expensive than a branch to a
lead cable network (block network). The aforementioned systems are generally called voltage systems,
because only voltages are applied to the connected parties, which then supply the energy that the
loudspeaker needs to function properly via amplifiers, etc.

The system of wire broadcasting at loudspeaker level used in
the Netherlands will be described in somewhat more detail here.

This system provides energy to connected parties, so that it is possible
to use the speaker immediately; However, this means that this energy must be the same everywhere. For
example, it should not be the case that one subscriber hears nothing, while the loudspeaker of the
other subscribers produces too much sound. This can easily be achieved with a good combination of
amplifiers and networks. If the cable conductors are thick enough so that no greater voltage losses
than 3 dB occur, the differences in strength are inaudible.

A second property that the wire broadcasting network must meet is a frequency characteristic that is as
straight [flat] as possible. As is known, the cable broadcasting stations transmit radio programs; these
consist of music and speech. The idea now is that when a tone of 6000 periods is produced for a microphone,
it will again be audible as a tone of 6000 periods.

In the beginning of wire broadcasting it often happened that a network was so large that it started to
prefer special frequencies; For example, if tone 6000 was sent from the exchange with 20 Volts in the
cables, it sometimes happened that 40 Volts or more were measured at certain places in the network;
this is an unacceptable change in the frequency characteristic; This unintentional increase in voltages
at certain frequencies is called resonances, which arise at distances of more than 2 km power cable
length. When designing a wire broadcasting network, care must therefore be taken not to use power cables
longer than 2 km.

*******

And a picture of the installation outside a building. A conduit appears to come from the ground, and two connections leave the top of the distribution box.
The screws on the box fashioned like a "security screw" for which the consumer does not have a tool to get it open. Implying that something
about the connections is "energetic".

https://en.wikipedia.org/wiki/Cable_radio#/media/File:GRD-Utrecht.JPG

Paul

As I've said, I had no idea NL had (has?) so many such systems!

I think the original Rediffusion system in UK died out because it became uneconomic, when the costs of radios (wirelesses) fell combined with the improvements in transmitter power and receiver sensitivity meaning large aerials were no longer needed. The company carried on for a while
distributing TV signals (I think their sets used 625-on-VHF [I'm
guessing band III as there was more room in it]), but even that
disappeared eventually.

I think the original - loudspeaker-level audio distribution - system
also suffered from piracy: if there was a cable passing your house,
tapping into it was fairly trivial if you didn't need anything more than
a speaker! (No, I'm not old enough to remember it. Can't swear I
wouldn't have though ...)
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf

The web is a blank slate; you can't design technology that is 'good'.
You can't design paper that you can only write good things on. There
are no good or evil tools. You can put an engine in an ambulance or a
tank. - Sir Tim Berners-Lee, Radio Times 2009-Jan-30 to -Feb-5.
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