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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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9th Feb 2007, 2:22 pm | #21 |
Retired Dormant Member
Join Date: Dec 2003
Location: North London, UK.
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Re: The earliest television aerials
Curious that they boast about a low capacitance. I thought the idea was to have a 75R constant impedance, the absolute values of inductance and capacitance are then irrelevant.
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9th Feb 2007, 2:59 pm | #22 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
Posts: 2,525
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Re: The earliest television aerials
The spec also mentions a capacitance at a certain frequency. Can capacitance as such vary with frequency then? (Obviously its effect will, but that's not the same thing). Somebody please put me right on this. I'm clearly ignorant on rf matters.
Steve PS. Hang on, it is something to do with 'skin effect' ?
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https://www.radiocraft.co.uk Last edited by Panrock; 9th Feb 2007 at 3:08 pm. Reason: Thought of something else |
9th Feb 2007, 6:28 pm | #23 | |
Dekatron
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,609
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Re: The earliest television aerials
Quote:
Regarding single dipoles the aerials, there were a few used for Band I in Bath, in districts that were higher up like Lansdown and Odd Down.
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Mike. |
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9th Feb 2007, 6:56 pm | #24 |
Retired Dormant Member
Join Date: Feb 2005
Location: Kingswinford, West Midlands
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Re: The earliest television aerials
In 1949 we had a 'H' aerial for a Philips 385U the lead was co-ax but had 2 cores, red & green this was wired directly into the set via a 3pin 2amp plug & socket so that the aerial could be unplugged and an extension plugged in so that the set could be moved to another room. There was also a thick red wire which came down from the aerial into the ground. I don't know what this arrangment would be called? some sort of screened twin feeder? maybe the set could accept this arrangment or a balanced feeder? would there be a transformer at the masthead or would each core go to each half of the dipole? what was the earth wire for?
Mick |