New technique?

Edinburgh Evening News - Wednesday 14 September 1938

POST OFFICE ACTS SUN-SPOT THREAT TO RADIO SPECIAL STATION AND NEW TECHNIQUE

Measures to combat intense sun-spot activity, which is expected to
interfere seriously with world radio communications in 1940, were
mentioned by Major G. C. Tryon, the Postmaster- General, at Newcastle
to-day.-

He said that the Post Office, following consultation with the American
telephone authorities, was constructing a special radio receiving
station. After long research, they had decided that the adverse effects
of sun-spot activity, which had been viewed with grave concern, could be
offset by adopting an entirely new technique in the reception of
shortwave transmissions.

ON PILES IN MARSHLAND
A building erected on 150 concrete piles, each about 80 feet deep, would
shortly be completed on marshland near Rochester, It would accommodate
six receivers for 12 circuits. The aerial system, consisting of 16
separate aerials, would be erected to face America. It was hoped that
the station would be in use early next year.

[Note.—On occasions of great sunspot activity, the conditions in the
upper atmosphere vary violently, giving rise to extremely bad short-wave
propagation conditions, and may even result in complete cessation of
short-wave signals, Such activity occurs in cycles of approximately 11
years. The new type of receiving aerial system is bound up chiefly with
the use of a number of receiving aerials suitably spaced in the
direction of the incoming signals.]

On 12/11/2023 10:07, JMB99 wrote:
> New technique?
>
>
>
> Edinburgh Evening News - Wednesday 14 September 1938
>
> POST OFFICE ACTS SUN-SPOT THREAT TO RADIO SPECIAL STATION AND NEW TECHNIQUE
>

Refers to Cooling Marshes - a friend's father worked there.

JMB99 <mb@nospam.net> wrote:

> New technique?
[...]

Diversity reception. A bank of identical receivers with their AGC lines
linked, whichever receives the strongest carrier suppresses the others.
Originally the P.O. and Bell Systems did it with relays and semi-manual
control, but the linked AGC system was used throughout WWII and well
into the 1960s.

The receivers could be connected to aerials with wide geographical
spacing, in which case the receivers were situated near the aerials and
the AGC lines were linked by landline. Alternatively, the receivers
were co-located but identical transmissions were sent simultaneously in
different wavebands, so the multipath fading effects were different for
each one.

Double-diversity needed four receivers: two different wavelengths and
two spaced aerials - I believe that was what the Bell/GPO system used.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

Sunday Mirror - Sunday 28 May 1939

Dog Saved Two Miles of Digging
EVERY dog has his day, but never has a dog had such a day as Rex, Home
Office trained Labrador.
By smelling what he thought was hundreds of cats, Rex saved the Post
Office two miles of digging.
The cat and dog idea was a brainwave. This is how it happened.
Sixteen miles of underground cables are connected to the new Post Office
" anti-sunspot" transatlantic radio-telephone receiving station being
built at Cooling Marshes, near Rochester, Kent.
One day it was noticed that the air in the maintain a high electrical
insulation, was leaking through a number of minute punctures.
Station Out of Action
The leakages put the cable, and consequently the station, out of action
and might have caused serious damage by permitting the infiltration of
water into the cable.
Mr. H. S. Lloyd, who trains dogs for the Home Office, was summoned.
He brought Rex with him, and a gas that smelt strongly of " eats "—that
is how the Post Office put it—was introduced into the air pumped into
the cable.
Rex was brilliant. They led him over the path of the cable. Every time
he smelt cats he set about digging furiously. He found fourteen leaks.

On 12/11/2023 11:30, Liz Tuddenham wrote:
> JMB99 <mb@nospam.net> wrote:
>
>> New technique?
> [...]
>
> Diversity reception. A bank of identical receivers with their AGC lines
> linked, whichever receives the strongest carrier suppresses the others.

There is a HE report on it.

Cooling Radio Station, Hoo Peninsula, Kent: An Archaeological
Investigation of a Short-Wave Receiving Station

Report Number:
110/2010
Series:
Research Department Reports
Pages:
73

It used MUSA then MEDUSA

JMB99 <mb@nospam.net> wrote:

> On 12/11/2023 11:30, Liz Tuddenham wrote:
> > JMB99 <mb@nospam.net> wrote:
> >
> >> New technique?
> > [...]
> >
> > Diversity reception. A bank of identical receivers with their AGC lines
> > linked, whichever receives the strongest carrier suppresses the others.
>
>
> There is a HE report on it.
>
> Cooling Radio Station, Hoo Peninsula, Kent: An Archaeological
> Investigation of a Short-Wave Receiving Station
>
> Report Number:
> 110/2010
> Series:
> Research Department Reports
> Pages:
> 73
>
> It used MUSA then MEDUSA

Thanks for that - so it was MUSA, not diversity..

I seem to remember reading about the American end of that system in
either the Bell Labs Record or the Bell System Technical Journal. There
were some interesting comments about the differences between Bell and
the G.P.O. in the attitudes they held towards their customers. Bell
wanted to reduce inconvenience to callers by providing a good
person-to-person service, even if it meant more apparatus - whereas the
G.P.O. wanted to optimise the use of minimal appartus even if it meant
inconveniencing their customers.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

Diversity reception. Its still done today, and nowadays phase as well as
strength are taken into account.
The big problem these days, and probably why there are not so many short
wave stations about, is man made interference for the general consumer.
Almost all your household gadgets make wide spectrum radio noise these days.
However go well away from civilisation and run from batteries and its
another world, or would be if the stations existed!
Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"JMB99" <mb@nospam.net> wrote in message news:uiq849$1up0$1@dont-email.me...
> New technique?
>
>
>
> Edinburgh Evening News - Wednesday 14 September 1938
>
> POST OFFICE ACTS SUN-SPOT THREAT TO RADIO SPECIAL STATION AND NEW
> TECHNIQUE
>
> Measures to combat intense sun-spot activity, which is expected to
> interfere seriously with world radio communications in 1940, were
> mentioned by Major G. C. Tryon, the Postmaster- General, at Newcastle
> to-day.-
>
> He said that the Post Office, following consultation with the American
> telephone authorities, was constructing a special radio receiving station.
> After long research, they had decided that the adverse effects of sun-spot
> activity, which had been viewed with grave concern, could be offset by
> adopting an entirely new technique in the reception of shortwave
> transmissions.
>
> ON PILES IN MARSHLAND
> A building erected on 150 concrete piles, each about 80 feet deep, would
> shortly be completed on marshland near Rochester, It would accommodate six
> receivers for 12 circuits. The aerial system, consisting of 16 separate
> aerials, would be erected to face America. It was hoped that the station
> would be in use early next year.
>
> [Note.-On occasions of great sunspot activity, the conditions in the upper
> atmosphere vary violently, giving rise to extremely bad short-wave
> propagation conditions, and may even result in complete cessation of
> short-wave signals, Such activity occurs in cycles of approximately 11
> years. The new type of receiving aerial system is bound up chiefly with
> the use of a number of receiving aerials suitably spaced in the direction
> of the incoming signals.]