Coax! Who could have imagined that a simple copper conductor with an insulator and shield would be so complicated!
First, let’s go over the most common 50-ohm coax types.
RG58
RG58 is the cheapest coax you can get. It is thin and very bendable. Very nice to use in the shack.
RG8X
RG8X is the standard in ham radio. Low attenuation on HF, affordable and common.
LMR-400
LMR-400 is the premium coax with low loss for long cable runs, especially for UHF/VHF.
Hardline
Hardline is for professionals. Not common, and extremely expensive. Very low loss.
Some say, ‘Use LMR-400 for everything!’ And if money were no option, this may be viable.
But what if I told you it is more complicated than that?
LMR-400 is great for long cable runs and is good for feeding VHF/UHF antennas.
Here is a table of RF signal attenuation for each coax (per 100 feet).
| LMR-1200 | LMR-900 | LMR-600 | 1/2” Superflex | LMR-400 | Belden 9913F7 | 9914 | RG214 RG213 | LMR-240 | Belden RG8X | LMR-200 | LMR-195 | RG-58/U | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frequency/Size | 1.200” | 0.870” | 0.590” | 0.520” | 0.405” | 0.405” | 0.400” | 0.405” | 0.240” | 0.242” | 0.195” | 0.195” | 0.195” |
| 30 MHz | 0.209 | 0.288 | 0.421 | 0.561 | 0.7 | 0.8 | 0.8 | 1.2 | 1.3 | 2.0 | 1.8 | 1.8 | 2.5 |
| 50 MHz | 0.272 | 0.374 | 0.547 | 0.730 | 0.9 | 1.1 | 1.1 | 1.6 | 1.7 | 2.5 | 2.3 | 2.3 | 3.1 |
| 150 MHz | 0.481 | 0.658 | 0.964 | 1.29 | 1.5 | 1.7 | 1.7 | 2.8 | 3.0 | 4.7 | 3.9 | 4.0 | 6.2 |
| 220 MHz | 0.589 | 0.803 | 1.18 | 1.58 | 1.8 | 2.1 | 2.1 | 3.5 | 3.7 | 6.0 | 4.8 | 4.8 | 7.4 |
| 450 MHz | 0.864 | 1.17 | 1.72 | 2.32 | 2.7 | 3.1 | 3.1 | 5.2 | 5.3 | 8.6 | 6.9 | 7.0 | 10.6 |
| 900 MHz | 1.27 | 1.70 | 2.50 | 3.41 | 3.9 | 4.4 | 4.5 | 8.0 | 7.6 | 12.8 | 9.9 | 9.9 | 16.5 |
| 1,500 MHz | 1.69 | 2.24 | 3.31 | 4.57 | 5.1 | 6.0 | 9.9 | 12.7 | 12.9 |
Now for the controversial opinion:
It is ok to use RG8X in the shack for 2M and 70cm.
Just keep the cable as short as possible. 25 feet of RG8X will not be noticeable if you are working repeaters.
RG8X on HF has low loss.
If you work 2M or 440 SSB/weak signal, you will want to use the lowest-loss coax possible. Also, keep in mind that more connectors = more loss.
In short: use any 50 ohm coax in the shack, it will be easier to use flexible coax between radios and tuners etc. Just try to keep the cable lengths short. Once you leave the shack, use the lowest-loss cable you can. These longer lengths will attenuate signals.
If you want the low-loss stuff, try the ultra-flex cable variants. Just be prepared to pay the premium.