Pre-war television OB aerial - UK Vintage Radio Repair and Restoration Discussion Forum

Panrock · 25th Dec 2016, 9:09 pm

In "The London Television Service" .pdf document recently posted in another thread, I noticed this transmitting aerial. It relayed television OB signals back to AP on 64MHz, and here it is seen at Wimbledon.

We are told it is a "two-stack balanced series phase array" and is vertically polarised.

Which are the active elements here? Is this some kind of slot aerial perhaps?

Just wondering!

Steve

G6Tanuki · 25th Dec 2016, 9:17 pm

I suspect it's a version of the array of phased dipoles in front of a 'mesh' reflector: this was a style of antenna used quite a bit by the Germans during WWII for radar:

http://www.gyges.dk/luftwaffe_radart...ecognition.htm

also known as a "billboard" antenna in the US: https://en.wikipedia.org/wiki/Reflective_array_antenna

Panrock · 25th Dec 2016, 9:34 pm

The strange thing in this example is that the aerial appears to have only one 'level', and where is the reflector? Could be a trick of the view though...?

Steve

G6Tanuki · 26th Dec 2016, 2:09 pm

It's tricky: even zooming-in and then electronically fiddling with the contrast then doing an 'edge-highlight' I can't actually see where the feeder is connected. The right-hand support pole has a cable/rope loosely wound several times around it midway up - could this be the feeder? Alas I can't see where it goes to higher up!

25th Dec 2016, 9:09 pm	#1
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,535	Pre-war television OB aerial In "The London Television Service" .pdf document recently posted in another thread, I noticed this transmitting aerial. It relayed television OB signals back to AP on 64MHz, and here it is seen at Wimbledon. We are told it is a "two-stack balanced series phase array" and is vertically polarised. Which are the active elements here? Is this some kind of slot aerial perhaps? Just wondering! Steve Attached Thumbnails __________________ https://www.radiocraft.co.uk

25th Dec 2016, 9:17 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,010	Re: Pre-war television OB aerial I suspect it's a version of the array of phased dipoles in front of a 'mesh' reflector: this was a style of antenna used quite a bit by the Germans during WWII for radar: http://www.gyges.dk/luftwaffe_radart...ecognition.htm also known as a "billboard" antenna in the US: https://en.wikipedia.org/wiki/Reflective_array_antenna

25th Dec 2016, 9:34 pm	#3
Panrock Nonode Join Date: Feb 2005 Location: Worcestershire, UK. Posts: 2,535	Re: Pre-war television OB aerial The strange thing in this example is that the aerial appears to have only one 'level', and where is the reflector? Could be a trick of the view though...? Steve __________________ https://www.radiocraft.co.uk

26th Dec 2016, 2:09 pm	#4
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,010	Re: Pre-war television OB aerial It's tricky: even zooming-in and then electronically fiddling with the contrast then doing an 'edge-highlight' I can't actually see where the feeder is connected. The right-hand support pole has a cable/rope loosely wound several times around it midway up - could this be the feeder? Alas I can't see where it goes to higher up!