Well, Dave: Let me take it point by point:
1) I am an MFG customer and while I might choose to design my stuff a little differently, I'm not trying to compete in the marketplace with others. I've not found my MFG equipment to be defective or needing "repair" out of the box. Indeed, their tuners are quite efficient and effective when used as recommended. 2) What do you mean by "out of the shack"? I assume it means that RF doesn't impair the operation of the rig or other equipment. Putting a low-impedance "ground" (in quotes with respect to the others who claim there is no such thing) at the rig does that. The "Artificial Ground" sold by MFJ does just that. I've used it and I know from experience. 3) You are quite right as Don also noted. A coaxial line laying on the ground running away from the antenna will intercept RF and have current flowing on the outside of the coax shield that is quite independent of the current flowing to the antenna on the inside of the shield. In that case, the objective is to stop those currents on the outside of the shield where the coax enters the shack as Don suggested. A coil of coax is a one way, although it's important to make it a coil, not a jumble-wound bunch of coax. In a bunch of coax wound up, it's possible for capacitive coupling between the coax at one end to the coax at the other end to eliminate most of the benefit of the inductance of the coil. Ron AC7AC ---------------------------------- Sorry, but I believe your posting to be full of bad advice. 1. Most bad reviews for companies that cater to hams are due to bad customer service. MFJ is one of the few that consistently gets bad marks for quality of construction and durability of use. If you don't believe that, you simply haven't been paying attention. 2. An "artificial ground" doesn't keep RF out of the shack ... it just tunes a low impedance path to something, which may or not be a ground of any sort. In any case, the chances of finding a functioning "RF ground" in an otherwise insulated basement room are not great. 3. Vertical antennas are notorious for putting RF on the coax shield when the coax is lying right alongside the radials. Why would you expect such an arrangement NOT to couple RF to the coax, and therefore right into the shack? Check around and you'll find all sorts of instances where people had such problems with a vertical antenna and used a current choke to fix it ... there are writeups everywhere on it. I agree with K9YC that a coil of coax will normally do the job just fine, although I'm not sure that the base of the antenna is always the best place to put it. If the coax is lying next to the radials it seems to me that there could still be a lot of coupling to the coax on the run to the shack. I'd be more inclined to put the choke closer to the house, but I'll defer judgment on that to the experts. Dave AB7E ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
