Very odd old aerial
 

Can someone explain the feed arrangement on this old BI 4X4

http://www.rhiw.com/hanes_02/rhiw_fi.../aerial_03.jpg

Parent article,

http://www.rhiw.com/hanes_02/rhiw_first_tv/rhiw.htm

--
Graham.
%Profound_observation%

Very odd old aerial
 

Sounds to me like the old saying is stood on its head here. Some words are
worth a thousand pictures.

Brian

--
--
From the sofa of Brian Gaff -

Blind user, so no pictures please!
"Graham." wrote in message
...

Can someone explain the feed arrangement on this old BI 4X4

http://www.rhiw.com/hanes_02/rhiw_fi.../aerial_03.jpg

Parent article,

http://www.rhiw.com/hanes_02/rhiw_first_tv/rhiw.htm

--
Graham.
%Profound_observation%

Very odd old aerial
 

"Graham." wrote in message
...

Can someone explain the feed arrangement on this old BI 4X4

Parent article,

http://www.rhiw.com/hanes_02/rhiw_first_tv/rhiw.htm

--
Graham. http://www.rhiw.com/hanes_02/rhiw_fi.../aerial_03.jpg


Graham
It's two four element vertical yagis for channel one (but you knew that),
as for the feed arrangement, well it might be each aerial is fed thru a
quarter wave transformer, for example if the yagis have a feed impedance of
35 ohms, a quarter wave of 75 ohm coax will transform this to roughly 150
ohms, (I didn't do the maths so roughly) then the two feeders in parallel
will match it to 75 ohms for the downlead. In the photo there doesn't seem
to be anything besides coax, but it could be other systems.
Nick

Very odd old aerial
 

On Monday, July 16th, 2012, at 10:36:10h +0300, Y Dangle suggested:

It's two four element vertical yagis for channel one

VHF Band I channel 2 surely?

Very odd old aerial
 

Yes, apologies, but don't call me Shirly.

"J G Miller" wrote in message
...
On Monday, July 16th, 2012, at 10:36:10h +0300, Y Dangle suggested:

It's two four element vertical yagis for channel one
.
VHF Band I channel 2 surely?

Very odd old aerial
 

_But_, in the very old days, I seem to remember, Crystal Palace was channel
1? (I know the US channels start at 2, but didn't ours start at 1?)

"Y Dangle" wrote in message
...
Yes, apologies, but don't call me Shirly.

"J G Miller" wrote in message
...
On Monday, July 16th, 2012, at 10:36:10h +0300, Y Dangle suggested:

It's two four element vertical yagis for channel one
.
VHF Band I channel 2 surely?

Very odd old aerial
 

I wish I could delete the last post - I now remember that Crystal Palace was
45MHz (or Mc/s then) so 51.75 IS ch 2.
So you are quite right.
....
_But_, in the very old days, I seem to remember, Crystal Palace was
channel 1? (I know the US channels start at 2, but didn't ours start at
1?)

VHF Band I channel 2 surely?

Very odd old aerial
 

On Monday, July 16th, 2012, at 13:06:07h +0300, Y Dangle pondered:

_But_, in the very old days, I seem to remember, Crystal Palace was channel
1? (I know the US channels start at 2, but didn't ours start at 1?)

That is correct.

But in the reported case, the viewer was trying to receive
not Crystal Palace VHF channel 1, but Holme Moss VHF channel 2.

Wikipedia explains the situation in North America --

Channel 1 was removed early on as a community television
reservation and given to amateur radio and other uses.

Very odd old aerial
 

On Monday, July 16th, 2012, at 12:23:38 +0000, J G Miller babbled:

Wikipedia explains the situation in North America --

And for those who despise and distrust Wonkeypedia,
here is the definitive article on the subject

"WHAT EVER HAPPENED TO CHANNEL 1?"

at

http://www.tech-notes.TV/History&Trivia/Channel%20One/Channel_1.htm

Very odd old aerial
 

In message , J G Miller
writes
On Monday, July 16th, 2012, at 13:06:07h +0300, Y Dangle pondered:

_But_, in the very old days, I seem to remember, Crystal Palace was channel
1? (I know the US channels start at 2, but didn't ours start at 1?)

That is correct.

But in the reported case, the viewer was trying to receive
not Crystal Palace VHF channel 1, but Holme Moss VHF channel 2.

Wikipedia explains the situation in North America --

Channel 1 was removed early on as a community television
reservation and given to amateur radio and other uses.

I'm pretty sure that the American 'Ch1' was in the frequency range of
what became the IF (45.75Mhz vision, 41.25MHz sound) when they started
making superhets - hence Ch2 is 55.25MHz.
--
Ian