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VK2TV > PLC 03.02.02 06:56l 87 Lines 3341 Bytes #-8140 (0) @ WW
BID : 37172_VK2TV
Read: GUEST
Subj: Re: What's the point.
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Sent: 020130/0649Z @:VK2TV.#MNC.NSW.AUS.OC #:28674 [Kempsey, QF68JX] $:37172_VK
From: VK2TV@VK2TV.#MNC.NSW.AUS.OC
To : PLC@WW
# Generated by: TstHWin v2.21b - Registered to VK2TV
# On : 30/01/02 17:48:05
# UTC: 30/01/02 06:48:05
Hi Bob, All,
I'm not taking sides on this issue or trying to take the mickey out of
anybody. I'm just relating my personal experience with control tones sent
over power lines.
>Norm, power authorities have been sending signals by the power lines for
>years. I casn remember about 40 years ago complaints that tones used to do
>this were interfering with hi fi setups and spoiling the enjoyment of
>those listening to music.
>
>I question your statement that amateur numbers are going to swell if morse
>testing is abandoned. Figures published by ZL2CA indicate quite clearly
>that the non code licences are dropping in number at least as quickly as
>the full licencees.
>
>Bob VK6BE.
>
>>
>> Basically it's High Speed Internet via the Power Lines similar to but
>> not the same as cable TV but instead of rolling out cable for the
>> carrier, PLC uses the existing Power Lines.
>
>>
>> The writings on the wall, get rid of Morse code as quickly as
>> possible and swell the amateur numbers on HF or just don't bother, cos
>> WHAT'S THE POINT if you can't use HF once PLC is introduced.
There is a vast difference between the "ripple control" systems used by
electricity authorities to switch, predominantly, but not exclusively,
off-peak hot water systems, and a continuous high frequency data stream
being transmitted via the electricity distribution system.
The authority for which I worked for over twenty years used the Zellweiger
(Switzerland) brand system and in our area the audio frequency was 1050Hz.
The electricity supplier on our southern boundary used 750Hz.
Although it's true that there was occasional complaints about interference
to audio equipment from the control tones, in my eighteen years in the
section that investigated these complaints (among other things), I could
count the number of complaints on my fingers and have fingers to spare! It
really was an insignificant problem.
The electricity generating authority in New South Wales, then known as the
Electricity Commission of NSW, had used LF carrier systems (in the range
150-400kHz, approximately) for many years for Telecontrol and other
communications functions between generating stations. Those carriers were
injected into the 330kV transmission system. Being analog, and at such
(relatively) low frequencies, they did not (to my knowledge) cause
interference to other communications systems. I certainly have never
experienced any problems while tuning that frequency range looking for
aircraft beacons, not even with a resonant antenna.
This is a far cry from the effects of transmitting a digital HF signal into
what could be classed as a reasonably effective antenna system.
We must be guided by those who have experienced the increased noise floor
during system trials.
Rest assured, however, that once a system is given approval it will never be
withdrawn from service simply because it's interfering with amateur hf
communications.
Regards ... Ray
Ray Wells
vk2tv@vk2tv.#mnc.nsw.aus.oc
mvc@midcoast.com.au
VK2TV is a HF/VHF/UHF digital forwarding station - helping to keep the radio in
amateur radio.
User-friendly HF ports at 300 baud on 7038.5 (LSB) and 10146.34 (LSB).
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