Difference between revisions of "Coax Cable for Ham Radio Applications"

Revision as of 00:49, 21 July 2016

Selecting the right cable for your radio transceiver installation is a balance between three primary factors:

1. Signal Loss
2. Cable Flexibility
3. Cost

In a perfect world you would have a relatively thin cable that was a perfect impedance match, well shielded, suffered from little to no signal loss, and was so flexible as to easily bend around tight corners and to the back of your transceiver. In the real world, no such cable exists. Everything is a compromise, the customary trade-off as with anything in life. The best shielded cables on the market are thick, lack flexibility, and are very costly. Cheap low-end CB radio cable is very flexible but loses signal readily. Signal loss is exacerbated as frequency is increased. Such signal loss is not as much of a problem in the HF radio bands as it is in the VHF and UHF bands. So, there's a lot to consider when purchasing cable for your mobile installation or a tower run into your ham shack.

In addition to cable signal loss, there are other issues to consider. Connector loss is another factor. SO239/PL259 is perfectly suitable for HF installation, including CB radio, not lossy when used on UHF installations. Cable durability is another factor. Your outdoor cable installation has to endure sunlight, the elements, and in some cases, squirrels and other critters. Mobile installations can often take even more abuse, especially under vehicle body cable runs (which should be avoided as a general rule.) Yes, you truly have a lot to consider when selecting the right wire for your transceiver signal fire. Power capacity, (if you are running an amp) may also become a factor.

Coaxial Cable Index

RG-59 or RG-6 should not be used for ham (75ohm TV)

RG-58 (CB cable) has a high loss factor in VHF and UHF frequencies, so it really only is useful in runs less than 50 feet for frequencies above 100 MHz, and 20 feet for frequencies above 400 MHz.

RG-8U is great for 50-75 foot runs in the VHF/UHF range.

UR67 or RG213 for 70cm.

LMR-400, Belden 9913 for 100 feet + in 70cm amateur radio, or GMRS.

RG8, RG8X, RG58U

RG58U

• more flexible
• lower cost
• good for short runs with mobile installations

RG8

• less loss on long runs 50ft - 100ft
• thicker and less flexible

RG8X (mini foam)

• smaller than RG8 with less loss than RG58U
• still not as good as RG8

NASA Coax Cable Loss Chart

RG213

RG-213/U is a low-loss, 50-ohm Coaxial Cable with a non-contaminating PVC jacket.