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Coax Cable and Connectors - For general discussion of all things pertaining to coax cable, wave guide or any other medium for passing RF energy. This includes connectors, weather proofing and grounding.

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Old 11-11-2008, 9:54 PM
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Default RG-6 Coax

I have seen guys use regular CATV type RG-6 coax cable scanner antenna feed line. What do you think of that?
I use this stuff all the time so I always have it on hand and have all the tools and high end connectors/splitters/etc.
Is this acceptable for "receive only"? Or should I stick with my RG8X?
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Old 11-11-2008, 10:04 PM
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Quote:
Originally Posted by petey_racer View Post
I have seen guys use regular CATV type RG-6 coax cable scanner antenna feed line. What do you think of that?
I use this stuff all the time so I always have it on hand and have all the tools and high end connectors/splitters/etc.
Is this acceptable for "receive only"? Or should I stick with my RG8X?

It is better than 8X

http://www.eweb-planet.com/kk6ss/coax.html
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Old 11-11-2008, 10:08 PM
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Thumbs up Rg-6

Quote:
Originally Posted by petey_racer View Post
I have seen guys use regular CATV type RG-6 coax cable scanner antenna feed line. What do you think of that?
I use this stuff all the time so I always have it on hand and have all the tools and high end connectors/splitters/etc.
Is this acceptable for "receive only"? Or should I stick with my RG8X?
RG-6 is perfectly acceptable for your receive antennas. Try it, you'll like it.
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Old 11-11-2008, 10:10 PM
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I'm about to run rg-6 for my discone to a distribution amp and 4-way splitter for 2 scanners and 2 PCR-100's, so far I am satisfied with the tests even with a 100 foot uncut feedline from the antenna.

I think it's okay, I used to hate on it but I have since changed my mind. Way cheaper and now that I am not going to move for a while, I can build an RX-only antenna setup - and thus use 75 ohm.
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Old 11-12-2008, 12:58 AM
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Question

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Originally Posted by N_Jay View Post
Ok here is a question. If it's better then RG8 then how's come there isn't a 50ohm version that's the same size? I hate the big fat cables but there is no 50ohm that is regular size like RG6.
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Old 11-12-2008, 1:25 AM
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Ok here is a question. If it's better then RG8 then how's come there isn't a 50ohm version that's the same size? I hate the big fat cables but there is no 50ohm that is regular size like RG6.
He said it's better than 8X. He didn't say it's better than RG8. Two different types of cables...

Regular size? No such thing... 50 ohm cable is available from less than an 1/8" (RG-174) to 1/4" (RG-58), 1/2" (RG-8) on up to 6" rigid. RG-8X is a bastard size between RG-58 and RG-8. There's plenty to chose from, and every one of them is a trade off in one way or another.
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Old 11-12-2008, 1:49 AM
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Quote:
Originally Posted by zz0468 View Post
He said it's better than 8X. He didn't say it's better than RG8. Two different types of cables...

Regular size? No such thing... 50 ohm cable is available from less than an 1/8" (RG-174) to 1/4" (RG-58), 1/2" (RG-8) on up to 6" rigid. RG-8X is a bastard size between RG-58 and RG-8. There's plenty to chose from, and every one of them is a trade off in one way or another.
people compare RG8 to RG6 in similar losses but RG8 is lots bigger. RG6 is the size of RG8x but it isn't' as lossy as RG8x. Why can't they make a RG6 size/characteristics that's 50ohm?

I know there are plenty to choose from, that's beside the point. and why can't people understand what i'm saying?
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Old 11-12-2008, 3:07 AM
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Maybe people can't understand what you're saying because you're not clear, or you misspeak. You said:
Quote:
If it's better then RG8 then how's come there isn't a 50ohm version that's the same size?
No one said RG6 was better than RG8. They said it was better than RG8X. Which isn't entirely accurate since RG8X is a mishmosh of different cable types/sizes that don't fit into the more standardized RG58 or RG8 categories, as zz0468 points out.



BTW, there is a 50 ohm cable close to the size of RG6...it's called TM LMR-300 or Belden 7809A

TM LMR-300: 50 ohm, 0.300 diameter, -2.4 dB/100' @ 150 MHz, -4.2 dB/100' @ 450 MHz, -6.1 dB/100' @ 900 MHz

Belden 7809A: 50 ohm, 0.300 diameter, -2.2 dB/100' @ 150 MHz, -3.9 dB/100' @ 450 MHz, -5.6 dB/100' @ 900 MHz


Incidentally, the 75 ohm version of LMR-300 has lower (better) attenuation than the 50 ohm version (although they are the same numbers as the Belden 50 ohm version). This is also true of the 75 ohm version of LMR-400, it has slightly lower attenuation than its 50 ohm counterpart.

TM LMR-300-75: 75 ohm, 0.300 diameter, -2.2 dB/100' @ 150 MHz, -3.9 dB/100' @ 450 MHz, -5.6 dB/100' @ 900 MHz


For the record, the losses shown for RG6 in that linked chart are inaccurate.

Belden 9116 RG6: 75 ohm, 0.270 diameter, -2.2 dB/100' @ 150 MHz, -4.3 dB/100' @ 450 MHz, -6.8 dB/100' @ 900 MHz


For comparison purposes...

TM LMR-400: 50 ohm, 0.405 diameter, -1.5 dB/100' @ 150 MHz, -2.7 dB/100' @ 450 MHz, -3.9 dB/100' @ 900 MHz

Belden 7809A: 50 ohm, 0.403 diameter, -1.5 dB/100' @ 150 MHz, -2.7 dB/100' @ 450 MHz, -3.8 dB/100' @ 900 MHz

Last edited by res6cue_dot_com; 11-12-2008 at 3:11 AM..
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Old 11-12-2008, 8:26 AM
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Quote:
Originally Posted by blueangel-eric View Post
Ok here is a question. If it's better then RG8 then how's come there isn't a 50ohm version that's the same size? I hate the big fat cables but there is no 50ohm that is regular size like RG6.
Because there is no big market for a low signal level 50 OHM cable.
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Old 11-12-2008, 1:24 PM
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Because there is no big market for a low signal level 50 OHM cable.
Ding! We have a winner.
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Old 11-13-2008, 1:55 PM
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OH RILLY? Manufacturers which use miles of it for internal wiring must be losers then.

Dang me, dang me
Aughtta take some coax and hang me
Hang me from the highest TREE...
Woman would you weep for me?

Roger Miller?
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Old 11-13-2008, 2:12 PM
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I suspect RG6 outsells everything else by a huge factor, considering how may people watch TV vs. how many people use radios....

Arrgh quit with the old songs, now that's stuck in my head...
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Old 11-13-2008, 7:05 PM
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Actually you can use RG6 for transmitting, but you'll have a 1.5:1 SWR (assuming a resonant antenna at the operating frequency). Do the math, 75/50 = 1.5

I'm not saying you should use RG6 for transmitting, but you could in a pinch.

I use RG6 from my Scantenna to a Stridsberg MCA204 multicoupler with very good results on 800 MHz.

Jon KF7YN
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Old 11-13-2008, 7:07 PM
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if size does matter....lol, rg-6 coax is ALOT less lossy, especially at 800 Mhz, than similiar sized rg-58 coax
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Old 11-13-2008, 8:33 PM
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Quote:
Originally Posted by kf7yn View Post
Actually you can use RG6 for transmitting, but you'll have a 1.5:1 SWR (assuming a resonant antenna at the operating frequency). Do the math, 75/50 = 1.5

I'm not saying you should use RG6 for transmitting, but you could in a pinch.

I use RG6 from my Scantenna to a Stridsberg MCA204 multicoupler with very good results on 800 MHz.

Jon KF7YN

Yes, but is designed for low loss and NOT power carrying capability.
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Old 11-13-2008, 9:45 PM
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50 ohms gives a conductor size ratio and spacing that grants the highest power handling capacity

additionally it is a pretty good halfway point between 36 ohm verticals and 72 ohm dipoles


75 ohms gives a ratio and spacing that provides for the lowest signal loss
hence its use in catv and rx only situations
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Old 11-13-2008, 11:21 PM
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Quote:
Originally Posted by jonny290 View Post
50 ohms gives a conductor size ratio and spacing that grants the highest power handling capacity

additionally it is a pretty good halfway point between 36 ohm verticals and 72 ohm dipoles


75 ohms gives a ratio and spacing that provides for the lowest signal loss
hence its use in catv and rx only situations
You sure? Why not 300 or 500 ohm for even lower loss?
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Old 11-14-2008, 2:55 PM
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Quote:
Originally Posted by blueangel-eric View Post
people compare RG8 to RG6 in similar losses but RG8 is lots bigger. RG6 is the size of RG8x but it isn't' as lossy as RG8x. Why can't they make a RG6 size/characteristics that's 50ohm?

I know there are plenty to choose from, that's beside the point. and why can't people understand what i'm saying?

RG-6 was designed for TV line, thus 75 ohm. It and RG8 were the "large wire standard" for 75 ohm and 50 ohm needs. The 'small wire standards' were RG 58 for 50 ohms and RG 59 for 75 ohms.

RG 8x is the compromise between "fat" RG 8 and "skinny" RG 58 in a 50 ohm design.

Wire makers can design pretty much anything you want....but the decision always breaks down to home much demand is there for what you want...can they make any $$ on it.

Wire manufacturers are just like any other business....they are in business to make money and everything they do is predicated on that.
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Old 11-14-2008, 3:57 PM
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Hey, if you have ready access to lots of RG-6, does that mean you have access to lots of RG-11? I've been using 11 with my Antennacraft ST-2 and it works awesome.
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Old 11-15-2008, 11:18 PM
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"You sure? Why not 300 or 500 ohm for even lower loss?"

How about 600 ohms? You're talking open wire feeder but I like your sarcasm N_Jay. Now here's something for you and it's not sarcasm, have you ever seen 50 ohm open wire coaxial transmission line?
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