Which of these is CT100 cable or equivalent?

[harrogate3]

twisted

In the radio business these days it is more common to use Andrews LDF series - that is low density foam filled. The type used in older days and especially for high powered Tx is the FHJ range which uses a helical polythene insulator. The reason for the latter? Because you can blow air through it to keep it cool.

The TV feeders at Emley are - I believe - aluminium and are about six inches diameter. DAB from the bottom of the tower uses something that looks like FHJ7-50 at about 2" diameter.

[Ashley Booth]

The TV feeders were made by a German company called KableMetall (sp?). Can't find much on the web, they seem to have been taken over by a French company.

They also supplied waveguide to one of the Goonhilly dishes.

[tony sayer]

Sounds about right and only 1.45 dB loss;))

DAB from the bottom of the tower uses something that

Usually in TV practice made by the Andrews corporation. Up to around 6 inches in diameter and more often than not solid sections and pressurised by dry nitrogen to keep the damp out!....

[Ashley Booth]

When working at a satellite tracking station in the 60s I had the job of logging the pressure in all the feeders. This was to spot leaks which usually meant the farmer had hit a cable with his machinery.

[Terry]

When I saw the Band I transmitter at Crystal Palace in the early 60's - Channel 1 (45.0MHz Vision, 41.5MHz Sound), the sound/vision diplexer was a magnificent piece of plumbing cooled by distilled water! A float viewed through a little glass window read 20L/min, IIRC.

Terry

[Bill Wright]

Yes it is, I've seen it and touched it. You couldn't fit a Poundshop belling plug on it that's for sure. I hope the gyppos never get in there with their chainsaws.

Bill

[Bill Wright]

That very good figure could be one reason why they had all that bother a while back, when they were radiating a 'ghost' on BBC1 analogue. Didn't it turn out to be due to a mismatch at the top end of the feeder?

Bill

[Geoff Winkless]

Geoff