Topband: Andrew RG6 specs ?
billw at waveform.net
Tue Mar 18 16:18:14 EDT 2014
Regarding the copper clad steel (CCS) center conductor, you can easily get RG6 with a solid bare copper (BC) center conductor too. BC center conductor is important for security cameras (which are baseband), and for satellite applications (which send DC over the center conductor to power the LNB at the dish). Since the satellite guys especially are also a very large market, there are lots of good BC center conductor RG6 variants to choose from at good prices.
Regarding the braid in the shield, Tom actually did some testing on that some time ago. I think he took a piece of the dielectric with the bonded foil ONLY (no braid) and measured essentially the same amount of leakage as the "regular" coax with the braid. I remember being surprised at that since I'd always thought of the foil as the high-frequency shield and the braid for the lower frequency part. I agree with you that I don't think I'd trust the light-braid RG6 variants for TX though since I'd be concerned about heating. Even though the foil is a good shield, there just isn't much metal there to carry the higher currents associated with transmitting.
BTW, you can even get RG6 with copper braid if you need solderability. It tends to be a lot more expensive though.
> loss doesn't matter for an RX antenna, but shielding does. Many CATV coax
> cables have shielding that is optimized for VHF/UHF, but not so great at MF
> (160M). Many also have a copper clad center conductor, which is fine for
> VHF/UHF, but more loss than copper at MF, which makes it less wonderful
> for TX.
> Take a look at the shield of any coax that you hope to use on MF and HF.
> If it's foil plus a thin braid, it will be lossy at MF/HF, and won't be a very good
> shield. If the SWR on the line is low, it may or may not handle much power.
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