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Discussion Starter · #1 ·
I posted this on HTF but I got no responses. I was curious if anyone over here could help me out? I found this cable at a weird stuff store in Sunnyvale. THe cable looked good it was cheap, $10 for 15' of four line cable.


The specs I got from Belden follow, this is old stuff, but how do the electrical properties look for component video? And how long does cable stay good for? I know the specs state how well the signal passes through the cable, but the number mean nothing to me, that's where I need help.


Thanks!



----------------------------------------------


12-15-89 REV. 0 YR-23028

DESCRIPTION:

75 OHM, 23 AWG SILVER PLATED COPPER COVERED STEEL, POLYETHYLENE INSULATED, 95% COPPER BRAID, 94% COPPER BRAID, BLACK PVC JACKET RG-59 COAX CABLE.


ELECTRICAL CHARACTERISTICS:

-----------------------------------

NOM. IMPEDANCE:_________________75 + 1-3 OHMS

MOM CAPACITANCE CONDUCTOR

TO SHIELD:______________________20.5 PF/FT

NOM. VELOCITY OF PROPAGATION:___66%

NOM. DELAY:_____________________1.54 NS/FT.

MAX OPERATING VOLTAGE:__________1400 V RMS

MAX OCNDUCTOR DC RESISTANCE

@ 25 DEG. C:____________________52 OHMS/1000 FT.

STRUCTURAL RETURN LOSS__________24 DB MIN., 5-600 MHZ

_____________________________20 DB MIN., 600-1000 MHZ

MAX ATTENUATION:

MHZ DB/100 FT.

400 9

1000 13



PHYSICAL CHARACTERISTICS:

-----------------------------------

TEMPATURE RATING:_______________-40 TO +75 DEG. C

MIN BENDING RADIUS:_____________2.64"

NOM. WEIGHT/1000 FT.:___________53.5 LBS.

CONDUCTOR MATERIAL & DIA.:______SILVER PLATED COPPER

________________________________COVERED STEEL, .0226" DIA

INSULATION MATERIAL & DIA.:_____.146" DIA.

SHILD TYPE AND % COVERAGE:______95% COPPER BRAID INNER

________________________________94% COPPER BRAID OUTTER


USE: SUITABLE FOR INDOOR AND OUTDOOF AERIAL APPLICATIONS
 

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Capacitance is decent though could be better.


Velocity of propogation is pretty high.


Resistance and attenuation are pretty hight too.


Double braid instead of foil and braid is nice.


The thing that would really turn me off to this is 'silver plated, copper covered steel.' STEEL!? No way for ANY type of audio or video cabling. You could probably use it as a hanger ;)
 

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Discussion Starter · #3 ·
bpape, thanks.


The silver coated copper covered steel was something I thought was a bit odd. Why steel is in there? Sounded odd to me.



I've got some followup questions.
Quote:
Velocity of propogation is pretty high.
This is good? From the research I've done I would think this is a good thing.

Quote:
Resistance and attenuation are pretty hight too.
High resistannce and attenuation never sound good.


The cables "look" good when connected, but that's like judging my tire pressure by eye.
 

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This is similar to the antenna cable I quit using in 1985. Copper-covered steel (usually called copperclad, do an internet search for it) is intended for RF frequencies as they travel on the skin of the wire.


Why the steel? It offers strength for a length of suspended wire. Think outdoors, think telephone poles. Most cable company RG-6 is copperclad for the same reason today, although there is usually also a 14 gauge "messenger," another separate steel cable to support the wire, attached to the wire that they drop from the pole to your house.


The DC components (well, 60 Hz sync pulses) of baseband video of any type -- composite, component, RGB) see a higher resistance than the higher frequencies because of the steel, so they are attenuated as though the wire is a smaller gauge.


Did I see that right? The wire is 23 gauge? That is going to be higher in resistance than normal RG-59, although it can still be 75 ohm impedance because impedance is a combination of resistance and reactances....


The steel and the copper have different velocities of propagation, so the near-DC and the high freq signals will arrive at slightly different times.


In short, use this cable for two-meter lengths or so, and it will be just fine. Ten meter lengths might just show a tiny lack of detail. 100 meter lengths will have problems.
 

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Yeah, I goofed. The Velocity of Propogation is LOW, not high. Not a good thing.


I still wouldn't use it. If it is that old, the silver and copper are probably degrading anyway.


But hey, if it looks OK to you , why not. I just wouldn't be happy knowing it could probably look better.
 

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Discussion Starter · #6 ·
See, that why I love this place I can get a good answer.

My concerns were the properties of the wire, and the age. I have no idea how long cable lasts. It should be pretty well sealed with the bnc connectors it has on it. The current lenght 5m is a bit long for what I need, but it looks as good if not better than the monster cables I had connected before.


I was really planning on going with the canare v3-5cfb component video cable. But then I saw this stuff and though... maybe it will work. I'll see if it can go back and I'll head down the canare path.


Thanks guys.
 
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