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OT UK Hi-Fi History



 
 
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  #1  
Old November 11th 16, 05:35 PM posted to uk.tech.digital-tv
R. Mark Clayton[_2_]
external usenet poster
 
Posts: 406
Default OT UK Hi-Fi History

On Tuesday, 18 October 2016 21:30:05 UTC+1, pinnerite wrote:
Jim Lesurf wrote:

Some here may have an interest in the history of UK Hi-Fi. With that in
mind I'm posting this to draw attention to the UK Hi-Fi History Society
website. The main webpage is at

http://www.torrens.org.uk/ukhhsoc/

But the main area of public interest at present is the 'Audio Documents'
collection whose top-level index is at

http://www.torrens.org.uk/ukhhsoc/AudioDocs.html

This currently provides over 2GB of scans of documents. The Audio
Documents are provided as a public resource for anyone interested in
aspects of the history.

We are continuing to seek, collect, scan, and add items. I'm currently
scanning many 'Radford' items, but have recently also been adding items to
the Armstrong, Leak, and J. E. Sugden sections.

Hope people find the content of interest. :-)

Jim


In the early 60s I designed Britain's first transistorised FM Tuner, the
Veritone Venus, just beating Truvox to that dubious honour. My employers
were such mean buggers that they wouldn't provide the necessary equipment.


I have got a Philips valve one in the garage. It does not work now :-(.
My parents acquired it ~1960.


An elderly manager at the placed suggested that I call Armstrong Audio, just
up the road if they would help. I spoke to Mr Rule their chief engineer and
explained my predicament. Although rivals he agreed to let me bring around
my prototype and tune the stereo decoder on their stereo signal generator.


IIRC the BBC did not bring in stereo on FM until much later, but can't find the date. It was in use by 1975 as I have a decoder chip from then.


He was a lovely man clearly keen to help an enthusiastic young kid.

But for him we would have had to continue to use our regular lab kit of an
Avo 8, the line timebase of a 405-line TV, the BBC late night 1 khz
reference tone, two 15 minutes per week of stereo, a 1.nnnnnn volt Leclanche
cell and a piece of wet string. We consistently claimed that the last item
was the most reliable but it always fell on deaf ears.

I still have photographs and possibly the wiring diagram and I think a PCB
board ... somewhere.

--
Mageia 5 for x86_64, Kernel:4.4.16-desktop-1.mga5
KDE version 4.14.5 on an AMD Phenom II X4 Black edition.


  #2  
Old November 12th 16, 08:00 AM posted to uk.tech.digital-tv
Mark Carver[_2_]
external usenet poster
 
Posts: 243
Default OT UK Hi-Fi History

On 11/11/2016 18:35, R. Mark Clayton wrote:


IIRC the BBC did not bring in stereo on FM until much later, but can't find the date.


Deepened where you lived. July 1966 on Wrotham for the Third Programme
(that became Radio 3 later)

1969 for R3 Sutton C and Holme Moss

1972 for R2 and 4 Wrotham, SC, and HM, then a slow national roll out

http://tx.mb21.co.uk/features/wrotham/chronology.php

--
Mark
Please replace invalid and invalid with gmx and net to reply.
  #3  
Old November 12th 16, 11:35 AM posted to uk.tech.digital-tv
Graham.[_7_]
external usenet poster
 
Posts: 9
Default OT UK Hi-Fi History

I just read about the Wrotham AM vs FM Band II tests. What was the radiated bandwith for AM?
More generally, what was the radiated bandwith for 405 line TV sound? I assume it was rather more than 9 kHz, but I really don't know.
  #4  
Old November 12th 16, 11:49 AM posted to uk.tech.digital-tv
Ian Jackson[_5_]
external usenet poster
 
Posts: 42
Default OT UK Hi-Fi History

In message ,
Graham. writes
I just read about the Wrotham AM vs FM Band II tests. What was the
radiated bandwith for AM?
More generally, what was the radiated bandwith for 405 line TV sound? I
assume it was rather more than 9 kHz, but I really don't know.


I believe that New Zealand was rather slow in introducing FM. The reason
was because it was considered that AM could probably provide an adequate
service. As they were so remote from the rest of the world, they could
transmit wideband Hi-Fi AM with little risk of causing interference to
anyone else.
--
Ian
  #5  
Old November 12th 16, 03:33 PM posted to uk.tech.digital-tv
Mark Carver[_2_]
external usenet poster
 
Posts: 243
Default OT UK Hi-Fi History

On 12/11/2016 12:49, Ian Jackson wrote:
In message ,
Graham. writes
I just read about the Wrotham AM vs FM Band II tests. What was the
radiated bandwith for AM?
More generally, what was the radiated bandwith for 405 line TV sound?
I assume it was rather more than 9 kHz, but I really don't know.


I believe that New Zealand was rather slow in introducing FM. The reason
was because it was considered that AM could probably provide an adequate
service. As they were so remote from the rest of the world, they could
transmit wideband Hi-Fi AM with little risk of causing interference to
anyone else.


AM in the US has a 10 kHz bandwidth, always has done. It sounds very
good, in fact better than some of our UK FM stations that insist upon
driving themselves into distortion, and compressing down to about 3dB of
dynamic range.

--
Mark
Please replace invalid and invalid with gmx and net to reply.
  #6  
Old November 13th 16, 01:42 AM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 1,544
Default OT UK Hi-Fi History

On 12/11/2016 16:33, Mark Carver wrote:
On 12/11/2016 12:49, Ian Jackson wrote:
In message ,
Graham. writes
I just read about the Wrotham AM vs FM Band II tests. What was the
radiated bandwith for AM?
More generally, what was the radiated bandwith for 405 line TV sound?
I assume it was rather more than 9 kHz, but I really don't know.


As a child I was aware of the difference between 405 line sound and AM
radio. In those days tellys had decent speakers so they sounded really
good. AM radio always sounded muffled.

When we started with FM CB in the UK the sound quality was nowhere near
as good as the illegal AM.

Bill

  #7  
Old November 13th 16, 08:12 AM posted to uk.tech.digital-tv
Ian Jackson[_5_]
external usenet poster
 
Posts: 42
Default OT UK Hi-Fi History

In message , Bill Wright
writes
On 12/11/2016 16:33, Mark Carver wrote:
On 12/11/2016 12:49, Ian Jackson wrote:
In message ,
Graham. writes
I just read about the Wrotham AM vs FM Band II tests. What was the
radiated bandwith for AM?
More generally, what was the radiated bandwith for 405 line TV sound?
I assume it was rather more than 9 kHz, but I really don't know.


As a child I was aware of the difference between 405 line sound and AM
radio. In those days tellys had decent speakers so they sounded really
good. AM radio always sounded muffled.

When we started with FM CB in the UK the sound quality was nowhere near
as good as the illegal AM.


The technology used in the FM-only UK sets was more-or-less identical to
the American sets - which were either AM, or AM plus SSB. Very few (if
any) had FM (not even sure whether FM was really allowed), and some of
the UK FM sets were merely modifications of AM circuits - and as such
were almost certainly not really optimised for best FM performance.

Even if they were capable of good performance, radio amateurs who
modified them for use on 29MHz often found that quite a few had rather
woolly audio, and the factory-set deviation was often well below the
correct +/-2.5kHz (possibly to compensate for the receiver IF filters
designed for 10kHz spacing on AM not necessarily being sharp enough for
adjacent-channel working on FM).

I also guess that opportunities were taken generally to minimise costs -
especially when the UK would be seen, when compared with the USA and
elsewhere, as somewhat of a niche market.


--
Ian
  #8  
Old November 13th 16, 08:37 AM posted to uk.tech.digital-tv
charles[_2_]
external usenet poster
 
Posts: 498
Default OT UK Hi-Fi History

In article ,
Ian Jackson wrote:
In message , Bill Wright
writes
On 12/11/2016 16:33, Mark Carver wrote:
On 12/11/2016 12:49, Ian Jackson wrote:
In message ,
Graham. writes
I just read about the Wrotham AM vs FM Band II tests. What was the
radiated bandwith for AM?
More generally, what was the radiated bandwith for 405 line TV sound?
I assume it was rather more than 9 kHz, but I really don't know.


As a child I was aware of the difference between 405 line sound and AM
radio. In those days tellys had decent speakers so they sounded really
good. AM radio always sounded muffled.

When we started with FM CB in the UK the sound quality was nowhere near
as good as the illegal AM.


The technology used in the FM-only UK sets was more-or-less identical to
the American sets - which were either AM, or AM plus SSB. Very few (if
any) had FM (not even sure whether FM was really allowed), and some of
the UK FM sets were merely modifications of AM circuits - and as such
were almost certainly not really optimised for best FM performance.


Even if they were capable of good performance, radio amateurs who
modified them for use on 29MHz often found that quite a few had rather
woolly audio, and the factory-set deviation was often well below the
correct +/-2.5kHz (possibly to compensate for the receiver IF filters
designed for 10kHz spacing on AM not necessarily being sharp enough for
adjacent-channel working on FM).


I also guess that opportunities were taken generally to minimise costs -
especially when the UK would be seen, when compared with the USA and
elsewhere, as somewhat of a niche market.


ISTR that the pre-emphasis on FM was different on the two sides of the
Altantic.

--
from KT24 in Surrey, England
  #9  
Old November 13th 16, 08:54 AM posted to uk.tech.digital-tv
Alan White[_3_]
external usenet poster
 
Posts: 62
Default OT UK Hi-Fi History

On Sun, 13 Nov 2016 09:37:39 +0000 (GMT), charles
wrote:

ISTR that the pre-emphasis on FM was different on the two sides of the
Altantic.


It was. 75 microseconds here, 50 microseconds there, or the other way
around.

--
Alan White
Mozilla Firefox and Forte Agent.
By Loch Long, twenty-eight miles NW of Glasgow, Scotland.
Webcam and weather:- http://windycroft.co.uk/weather
  #10  
Old November 13th 16, 08:56 AM posted to uk.tech.digital-tv
Ian Jackson[_5_]
external usenet poster
 
Posts: 42
Default OT UK Hi-Fi History

In message , charles
writes
In article ,
Ian Jackson wrote:
In message , Bill Wright
writes
On 12/11/2016 16:33, Mark Carver wrote:
On 12/11/2016 12:49, Ian Jackson wrote:
In message ,
Graham. writes
I just read about the Wrotham AM vs FM Band II tests. What was the
radiated bandwith for AM?
More generally, what was the radiated bandwith for 405 line TV sound?
I assume it was rather more than 9 kHz, but I really don't know.

As a child I was aware of the difference between 405 line sound and AM
radio. In those days tellys had decent speakers so they sounded really
good. AM radio always sounded muffled.

When we started with FM CB in the UK the sound quality was nowhere near
as good as the illegal AM.


The technology used in the FM-only UK sets was more-or-less identical to
the American sets - which were either AM, or AM plus SSB. Very few (if
any) had FM (not even sure whether FM was really allowed), and some of
the UK FM sets were merely modifications of AM circuits - and as such
were almost certainly not really optimised for best FM performance.


Even if they were capable of good performance, radio amateurs who
modified them for use on 29MHz often found that quite a few had rather
woolly audio, and the factory-set deviation was often well below the
correct +/-2.5kHz (possibly to compensate for the receiver IF filters
designed for 10kHz spacing on AM not necessarily being sharp enough for
adjacent-channel working on FM).


I also guess that opportunities were taken generally to minimise costs -
especially when the UK would be seen, when compared with the USA and
elsewhere, as somewhat of a niche market.


ISTR that the pre-emphasis on FM was different on the two sides of the
Altantic.

Broadcast FM radio is indeed slightly different (75us in the USA, and
50us in most of the rest of the world) - but I was commenting on
possible causes for poor quality audio with legal (FM) CB radios (quite
different!).
--
Ian
 




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