What do those masts do?? - UK Vintage Radio Repair and Restoration Discussion Forum

TrevorM6TSE · 22nd Mar 2004, 5:27 pm

Hi All,

One thing that has always intersted me is what do those big mast things do?? (sorry if I'm dim!!)

The ones I mean are like the ones just off the M60 in Manchester, and for that matter, all over!!

They look like a tall (about the height of a pylon) metal stalk like structure like scaffolding with a number of cables going from the top to the bottom all around it. Kind of like a big teepee without the cloth!!

Again, sorry if I'm dim, but it's always puzzled me what they do and how they work.

Thanks

ppppenguin · 22nd Mar 2004, 5:44 pm

Probably mobile phone base stations. They come in various disguises including, so I've heard, trees and church tower ornaments!

TrevorM6TSE · 22nd Mar 2004, 5:53 pm

I've always thought they were VLF transmitters, but can't be sure. There a normally five or six of them in a field.

Tim · 22nd Mar 2004, 5:55 pm

Also,now apparenly inside some petrol station fourcourt signs. So how come it's illegal to use your mobile there?
Are they in fact more concerned the signal from the mobile may affect the pumps as sometimes happened in the early days of CB radio.?
No doubt the forum has the answer............

Tim

TrevorM6TSE · 22nd Mar 2004, 5:57 pm

Back to the masts

Here is a pic of what I mean:

http://www.subbrit.org.uk/sb-sites/s...io/index.shtml

HELP!!!

Tim · 22nd Mar 2004, 6:29 pm

The page to which the link points explains it fairly well.

jim_beacon · 22nd Mar 2004, 6:34 pm

Trev, the masts in the picture are the old VLF / LF aray at Rugby, operating the 60KHz MSF standard time and frequency service, and (the now closed) 16KHz teleprinter service for the Navy. When I went past a couple of months ago, the 16KHz aray (at the top of the masts) had been removed, so I suspect they are about to remove some of the masts.

I think the masts you are talking about are MW stations, often grouped to provide directional coverage of a geographic area. You may find the wires are just guys, they may be the aerial itself, or they may provide capacitance loading of the mast.

The usual design is to stand the metal mast structure on insulators, and break the guys with insulators at some distance from the top. It is then possible to load the mast as the radiating element, with the top section of the guys acting as a capacitance " hat " to improve matching (this method is also used for aviation NDB's(Non Directional Beacons), which work at MF). The directional capability is achieved by feeding a number of radiators in a specific phase arrangement, which will generate a directional radiation pattern.

These arrangements require a very good earth, so the sites will often be on low lying, semi waterlogged ground, with a huge copper earthmat buried in it!

Hope that answers your question.

Jim.

TrevorM6TSE · 22nd Mar 2004, 6:54 pm

Thanks Jim!

It does!!

(PS Misus is OK about the record player!! Yipee)

audiomagpie · 22nd Mar 2004, 11:35 pm

My landing window looks over this site, about a mile away. They are due to be dismantled within the next couple of years. I for one will kind of miss them, they guide me home, especially when lit up

22nd Mar 2004, 5:27 pm	#1
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 540	What do those masts do?? Hi All, One thing that has always intersted me is what do those big mast things do?? (sorry if I'm dim!!) The ones I mean are like the ones just off the M60 in Manchester, and for that matter, all over!! They look like a tall (about the height of a pylon) metal stalk like structure like scaffolding with a number of cables going from the top to the bottom all around it. Kind of like a big teepee without the cloth!! Again, sorry if I'm dim, but it's always puzzled me what they do and how they work. Thanks __________________ I'd just like to say "Good luck, we're all counting on you"

22nd Mar 2004, 5:44 pm	#2
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: What do those masts do?? Probably mobile phone base stations. They come in various disguises including, so I've heard, trees and church tower ornaments!

22nd Mar 2004, 5:53 pm	#3
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 540	Re: What do those masts do?? I've always thought they were VLF transmitters, but can't be sure. There a normally five or six of them in a field. __________________ I'd just like to say "Good luck, we're all counting on you"

22nd Mar 2004, 5:55 pm	#4
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: What do those masts do?? Also,now apparenly inside some petrol station fourcourt signs. So how come it's illegal to use your mobile there? Are they in fact more concerned the signal from the mobile may affect the pumps as sometimes happened in the early days of CB radio.? No doubt the forum has the answer............ Tim __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

22nd Mar 2004, 5:57 pm	#5
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 540	Re: What do those masts do?? Back to the masts Here is a pic of what I mean: http://www.subbrit.org.uk/sb-sites/s...io/index.shtml HELP!!! __________________ I'd just like to say "Good luck, we're all counting on you"

22nd Mar 2004, 6:29 pm	#6
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: What do those masts do?? The page to which the link points explains it fairly well. __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

22nd Mar 2004, 6:34 pm	#7
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: What do those masts do?? Trev, the masts in the picture are the old VLF / LF aray at Rugby, operating the 60KHz MSF standard time and frequency service, and (the now closed) 16KHz teleprinter service for the Navy. When I went past a couple of months ago, the 16KHz aray (at the top of the masts) had been removed, so I suspect they are about to remove some of the masts. I think the masts you are talking about are MW stations, often grouped to provide directional coverage of a geographic area. You may find the wires are just guys, they may be the aerial itself, or they may provide capacitance loading of the mast. The usual design is to stand the metal mast structure on insulators, and break the guys with insulators at some distance from the top. It is then possible to load the mast as the radiating element, with the top section of the guys acting as a capacitance " hat " to improve matching (this method is also used for aviation NDB's(Non Directional Beacons), which work at MF). The directional capability is achieved by feeding a number of radiators in a specific phase arrangement, which will generate a directional radiation pattern. These arrangements require a very good earth, so the sites will often be on low lying, semi waterlogged ground, with a huge copper earthmat buried in it! Hope that answers your question. Jim.

22nd Mar 2004, 6:54 pm	#8
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 540	Re: What do those masts do?? Thanks Jim! It does!! (PS Misus is OK about the record player!! Yipee) __________________ I'd just like to say "Good luck, we're all counting on you"

22nd Mar 2004, 11:35 pm	#9
audiomagpie Heptode Join Date: Apr 2003 Location: Rugby, Warwickshire, UK. Posts: 825	Re: What do those masts do?? My landing window looks over this site, about a mile away. They are due to be dismantled within the next couple of years. I for one will kind of miss them, they guide me home, especially when lit up __________________ Greg BVWS committee chairman