DE7202699U - Low-radiation and interference-free coaxial cable - Google Patents

Description

STANDARD ELECTRICS LORENZ
SHARED COMPANY

Stuttgart

G. Buhmann - 18

Low-radiation and interference-free coaxial cable

For community antenna systems and large community antenna systems coaxial cables are required, even with very high frequencies are low in radiation and free from interference. Such cables are operated at frequencies of up to 800 MHz and the cooling resistance is used as a measure of the screen quality verver.det, which e.g. at 200 MHz must not exceed a certain value-

De ^ like Ka el should continue to have the property that they are equally suitable for the be suitable outside and inside of "ebäuder should.

In addition, these coaxial cables should be resistant to aging, i.e. the damping may be used in an aging test according to the standard do not increase by more than 10 <£.

Finally, such a coaxial cable should also be largely insensitive to thermal and mechanical stress so that even after the laying or a corresponding stress on the spot, the after the Manufacture of the existing screening quality, as well as the wave resistance and reflection factor is retained.

The well-known coaxial cable, which consists of a braided copper wire have existing outer conductors, meet

January 20, 1972

Gust / mr - / -

Π. Buhmann - l8

these demands do not; for example v; will be because of of the electrically permeable mesh the required Coupling resistance exceeded significantly because this is 3-10 MKr due to the inductance of the braid. away again increases linearly with frequency. In principle, coaxial cables with an outer conductor made from double braid also show the same properties, so that they do not achieve the screening quality required for the application.

Also the well-known CCITT coaxial conductors 1,2 / 4,4 bw used in telephone cables. Meet 2.6 / 9.9 the requirements mentioned at the beginning do not. It is true that these coaxial conductors have a lengthways made of a copper tape outer conductor molded around the dielectric. The copper band, however, only has butt butted longitudinal edges applied so that one along the entire outer conductor running narrow longitudinal gap remains, so that this coaxial conductor is electrical at high frequencies is so primeval that it does not have the required screening quality.

In order to overcome this problem, it has been proposed to use a completely closed metal tube for the outer conductor to use. Such a metal tube can, for example, be a seamlessly drawn aluminum tube or one lengthways around the Dielectric to the outer conductor formed copper or aluminum tape whose butt juxtaposed longitudinal edges are welded or soldered. Such outer conductors can either be smooth or - to improve bending behavior - also be corrugated.

The production of these outer conductors is too expensive and in view of the desired moderate price of the coaxial cable uneconomical. In addition, this Her * -

~. Duhmann - 18

stellur.c; swei se additional, often not or in not A sufficient number of existing production facilities is required, which is also disadvantageous.

It is therefore the task of the application to provide a low-radiation and interference-free up to very high frequencies for the Indicate the laying of coaxial cables in the ground and laying outside and inside buildings, that consists of a solid inner conductor made of a material that conducts electricity well, a homogeneous dielectric Plastic and a strip made of a material with good electrical conductivity, which is formed lengthways around the dielectric to form the outer conductor consists.

This object is achieved according to the invention in that the longitudinal edges of the bare metal outer conductor land

it) overlap each other and a so-called one above the outer conductor Layered jacket is arranged, consisting of a longitudinally with an overlap over the outer conductor with Plastic-coated copper or aluminum tape, where the plastic is welded to the overlap, and a plastic jacket disposed over the coated tape and welded to it.

The ones mentioned at the beginning of a low-radiation coaxial cable The requirements set are fully met with the new coaxial cable. Even with a slight overlap of the long edges of the outer conductor tape, a significantly improved screening quality is achieved.

If only a plastic jacket were to be used over this outer conductor, For example, made of polyethylene, applied, it would be a relatively short time after installation, especially with underground cables, due to the water vapor permeability of the plastic, moisture through the plastic

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O. Buhmann - 18

penetrate the jacket and corrode the overlapped points of the outer conductor · " ¹ tape, so that the contact would gradually be interrupted. An interrupted contact at the point of overlap means abe ¹ - again a gap that is electrically permeable. An overlapped, long-running copper tape is only electrically tight if the overlap has good electrical contact and maintains it even after a long period of time.

The layered coat over the longitudinal, overlapped

"10 outer conductor tape ensures that no moisture penetrates the cable and that the original contact quality is retained at the overlap, which means that the original shielding quality is retained for a long time bending stresses it changes its circumference substantially less than a normale- rolyäthylenmantel This is particularly advantageous f "r the preservation of ^{Wellenwiderstan-:.} it and low reflections. The solid or foam polyethylene of the dielectric between the inner conductor and outer conductor of the coaxial cable offers the outer conductor tube a firm support at the same time. The layered cladding on top prevents the outer conductor from opening and thus a reduction in capacitance, an increase in the wave resistance and thus also contributes to maintaining the longitudinal uniformity (lower reflection factors).

To ensure the quality of the new coaxial cable, a contribution is made during manufacture if the outer conductor is helical wrapped in plastic or metal tape j50. As a result, the layer before the layer is applied the outer conductor strip, which is formed into a tube, is fixed tightly to the dielectric. The helically wound Tape (thin plastic or metal foil) can

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G. Buhmann - 18

during the subsequent application of the layered cladding tape with the inner plastic layer of the tape are welded or glued.

The sr; hichter Moisture barrier; In addition, however, the layered cladding band contributes to a further, considerable one Increase in the S-hirr.igUte of the coaxial cable.

An optimal effect both h ^: r.sichtl ^; The noise level and the resistance to alteration occur when the overlap of the outer duct and the coated one. Ribbon on the cable circumference are offset from one another by l8o Wi nice lgr ade.

The minimum overlap; ^r , of the outer conductor bar, is dependent on the required coupling before the required coupling and is also dependent on the surface quality of the strip and the contact ar of the overlap. "IuQt, so that lnb'gl'.chst firm contact (close to the overlap point) is desired. With dUr.ner. Cables: .s': · a M"r.destüberlappunp; from J) - 5 mm necessary, be ^; . thicker KaDeI ^. The overlap can be a little higher.

The new cable also has nonta ^ etechv. ^: .sehe Vorte'.Ie, since v.ach remover .. "des Schlchter.mar.tels e ^{: r} ~. bare outer conductor releases, the verb '" idar.gm:with the neighboring cable, the: amplifier or e'nem Plug keLr.erle 'Schv, ^T ier- ^: gkeiter. prepares

In the attached? I ^ ur the new Kabela ~ "^ au ar.iiand a sectional b" lcies can be recognized. As Inr.e "le"^; . ter 1 dle-t a solid copper wire. The dielectric 2 consists of homoce ^ en or foamed polyethylene. The outer conductor 5, ^ O, which consists of 0.1 to 0.2 nm thick copper or aluminum ribbon, is overlapped at 7, - "no

very a about, form i g

G. 3uhtnann - Io

a plastic tape -. rze: i ± c \ '. elt. The layered jacket consists of: both sides with plastic: coated aluminum. G.

3 claims for protection,

1 sheet of drawings mi

Ί rifur

7202693-8.6.7?

Claims (2)

1, Buhnann - Yc protection claims 1.31ε too high Freoue ze: spotlights, "sarnes .nc ³ stör 'r: sfreves, ^r ' üi ° the burial ud d ^: e"erlerur--; except- v.-ri
within "ebäuden alike ^gee: Grete"^oa>: el: abel m "t a massive inner conductor, e ': he _ä homogeneous" D Electric "'. ur out.?" unststof 'and a County ^ s for. : aas D 'electric current; zurr:
Outsider _r ~ e'ormter. Band from electrically gut le'ter.de ~
Material. This means that the lan; s'-ca-.r, en of the metal ^: bare outer conductors overlap and a so-called layered jacket is arranged over the outer conductor, oesteh ^e rd as a lan: s m't overlap. "on the outside: ladder applied- nr t? 'urststo:' f coated copper or aluminum tape, where the overlap
the plastic is welded, and ^e: NEN above the = - coated 3and arranged and welded with this plastic sheath. 2.Koaxialkabel räch claim 1, characterized in that this
The outer screw-shaped slider is wrapped in a plastic or metal tape. Characterized ^ .Koaxialkabel according to claims 1 and that the ÜberlapOunp?; of the outer conductor strip and
of the coated tape on the cable around 16o degrees from each other ^{: are} arranged offset from one another.