Coax cable for feedline?

[Fuzy_GSXR1000]

Today I was in Home Depot and noticed they have RG-6X I think 100 feet for $25.00 and 50 feet for less Is this accepctable for connecting a radio to antenna? I keep reading about RG-8 so I was wondering the lower the number the heavier the wire or copper correct?

[prcguy]

The RG# has nothing to do with wire size or copper content. What kind of radio and antenna are you connecting?

RG-6 is 75 ohm general purpose for TV and satellite receivers while RG-8 is a reasonably low loss 50 ohm cable for amateur radio/CB, etc.
prcguy

Originally Posted by Fuzy_GSXR1000

Today I was in Home Depot and noticed they have RG-6X I think 100 feet for $25.00 and 50 feet for less Is this accepctable for connecting a radio to antenna? I keep reading about RG-8 so I was wondering the lower the number the heavier the wire or copper correct?

[mrweather]

It depends what you plan to do with the cable. If you're simply connecting a receiver, the RG6 will work. If you want to transmit, you'll need something that has the same impedence as the radio and antenna, eg. RG8.

[Fuzy_GSXR1000]

Thanks guys yes it would be to transmit as well as receiving!!!

[N8IAA]

Originally Posted by Fuzy_GSXR1000

Thanks guys yes it would be to transmit as well as receiving!!!

Depends on the frequencies, too. But, RG-8 and RG-8 mini will work well with longer runs on HF, and shorter runs on VHF/UHF.
Larry

[Ed_Seedhouse]

75 ohm cable into a 50 ohm transmitter gives an SWR between the transmitter and the cable of 1.5 to one, if I recall my introductory course correctly. This is really not very much and might work OK depending on the transmitter, power, and the match at the other end to the antenna. A 1.5 to one SWR gives a transmission loss of 0.18 db according to the chart at this site: VSWR

If your transmitter has a transmatch built in, as many commercial HF rigs do, the SWR can be bought down to 1:1 anyway.

Less than 0.2db due to impedance mismatch is surely inconsequential loss and for instance common RG8X has a loss at 100mhz of 3.6 db per 100 feet vs only 2 db per 100 for RG6. So the SWR loss may be paid for by less loss on the transmission line depending on the situation.

Common cables transmission loss table here: http://www.w4rp.com/ref/coax.html

[mrweather]

True, 75 ohm cable can be used as it will show a slight mismatch when being used with a 50 ohm system.

It's just easier to recommend 50 ohm cable and avoid the esoteric discussion.

[LtDoc]

There are three thing to which coax cable to use. It's characteristic impedance, it's losses, and cost. Part of one of those things is the ease in putting connectors on it too. Most commercially made 'ham' equipment uses a PL-259/SO-239 connector. They can be put on RG-6 but not very easily (for me). That's the biggest reason why I don't use it, along with it being 75 ohm instead of 50 ohm impedance.
If you wanna try it, do so.
- 'Doc