My thoughts about almost everything
April 19th, 2020
RG6 for Ham Radio?
I am one of those guys that like to think we know a lot of things… a smart guy. Well, I am smart enough to know that I do NOT know everything about anything and that fact becomes more apparent every day. So, now that you know I am just an average guy, we can go on.
If you were to ask 10 different Hams about the best feedline to use, you would get 15 different answers. It’s generally agreed that the open-wire feed line is the best in most cases. This is especially true when you are using a balanced wire antenna. It has very low loss and magically turns a single band dipole into a multi-band doublet. In almost every case, it will require a balun or unun of some type but that is another topic for another time. I am ready for it… what about the G5RV? It doesn’t use a balun. Well, no it doesn’t REQUIRE one but most people will agree that at some point before it enters your shack, you should have a 1:1 isolation balun to keep common mode currents out of your shack and I have seen it recommended that the balun should be at the junction of the coax and window line. Well, I tried that once and the G5RV wouldn’t tune very well. But we are not talking about antenna types or baluns or ununs today. We are talking about using common old RG6 Cable TV coaxial cable as an antenna feed line for both transmitting and receiving. Let’s get on with that.
It is a common misconception that with coaxial cable, price equates to quality and efficiency. In many if not most cases, that may be true but it is not true in all cases. I was convinced that because of it’s moderate cost, easy availability, rugged jacket and impressively low (for its price) loss numbers RG213 was the coax to use for everything until a friend of mine told me that he has been using RG6 for quite some time. RG6??? Well, he knows more than I do about it so I did some research. I found that the RG6 had loss specs close enough to RG213 (and in some cases…better) that for a receive antenna it might be ideal. But what about transmitting? Well, my friend told me that he believes it works every bit as well as RG213 or RG8. He, like me, never runs over 100w to transmit so I tried it. I found that as far as I could tell and based on signal reports and RBN results when testing, it worked as well as or better than RG213! OK… there has to be something wrong here. How can coax that costs fifteen cents or less per foot (I just purchased 250’ for $29.00) work as well as the stuff that costs almost a dollar per foot? Well, there’s one of those gotchas. It can’t work as well in every case. The dielectric is foam and the cable is about the same size as RG8x or LMR240 so it is unlikely it could handle power levels much over a couple of hundred watts. I found conflicting specs related to breakdown voltage so I can’t really comment on that. The next gotcha comes into play when you want to install a PL259 to connect the coax. The RG6 coax has a 100% aluminum foil shield and a 40% (some types have more) braided wire shield but it is aluminum so soldering the shield is pretty much impossible. There are, however, a couple of ways to make it work. The center conductor in most types of RG6 is copper clad steel so it can be soldered and that will give the PL259 connection some added strength. There are two ways I have found to connect the PL259 to the RG6 that have been very reliable for me. As soon as they are uploaded, I will include links to videos at the end of this article so I can show you how I do it. Once the connectors are added and weatherproofed, the RG6 coax seems to perform very well, resists sunlight and weather very well and as an added bonus, it is very light so there is low stress on the connectors when used with a wire antenna and suspended above the ground.
RG6 may not be the best choice in every application but for low power Ham Radio use, I have had great results and can say without incertitude that you should experiment with it and see how it works for you.
David E Belville