Re: Topband: Beverage Feed-line Noise Pickup
Bruce -- The coax isn't buried. A lot of it runs across a concrete pool deck, and then up to a second floor window, so no chance to bury it. For the 31-material snap-on chokes, I use 8 turns of RG-58-whatever through the center. See the illustrations in Jim Brown's piece for how to wind them so as to minimize capacitance between the turns, which affects the resonant frequency of the choke. -- Art, KB3FJO From: K1FZ-Bruce <k...@myfairpoint.net> Sent: Thursday, December 1, 2016 11:50 PM To: Arthur Delibert Subject: Re: Topband: Beverage Feed-line Noise Pickup Art, Wonder if you have your coax cable buried ? How many turns are you using thru your Ferite 31 cores? Many thanks, Bruce-k1fz. On Fri, 2 Dec 2016 03:24:30 +, Arthur Delibert <radio7...@msn.com> wrote: Herb -- I don't have Beverages, but rather pennant antennas. I think we have potential problems at both ends of the feedline and need protection at both ends. I use Fair-Rite 31-material snap-on cores at both ends, and there's a noticeable difference in the noise level if I remove either one. I suggest you check out "A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing," by Jim Brown, K9YC, which can be found at http://www.k9yc.com/RFI-Ham.pdf. I found it very helpful in understanding that problem and others, and have been able to do a lot to reduce the amount of locally-generated noise that finds its way into the shack. Hope this helps. Art Delibert KB3FJO From: Topband <topband-boun...@contesting.com> on behalf of Herbert Schoenbohm <he...@vitelcom.net> Sent: Thursday, December 1, 2016 12:06 PM To: Topband Subject: Topband: Beverage Feed-line Noise Pickup On my Beverage feed-line RG6 runs (some 200 feet) I use multi-turns a large toroid on each feed-line and the attach each coax to a grounding block and good ground rods (typical Hume Depot RG-6 variety) then on the other side of the grounding block before the coax runs about 20 feet to the Beverage Switch I have another large wound 13 turn toroid. I have since learned that I probably have all my feed-line noise suppression stuff in the wrong place and that the equipment side toroids are probably useless anyway. Now I am told that this noise pickup suppression stuff needs to be out by the actual Beverage feed and about 20-30 feet away. The reasoning is that the noise pickup by the feed-line needs to be blocked from coupling into the antenna itself. Is this true? I am starting to move the toroid-ground-toriod RG-6 "T" combos out closer to the antennas. I noticed that DX-Engineering sells an RFCC-1 box designed for Beverage coax runs but suggests it be place about 20 to 30' from the Beverage feed which has it's own separate ground rod. I bought one and before I put it out near the Beverage feed I thought I would it in place of the toroid system near the shack on one of the Beverage feedlines. However when I grounded the unit to the Beverage ground system near the shack I immediately noticed the noise floor jump up by about 10 db. I now know it is in the wrong place but this test with the DXE RFCC-1 may prove something of interest. Please correct my assumption if it is wrong: Noise pickup from long Beverage feed-lines flows back toward the Beverage feed point and then it is coupled via the feed point transformer back down the center conductor to the receiver. If this is true I will remove all toroids at the house and put them out near Beverage feed points (about 30 feet away with separate grounds based on the advice I receive back from this post. Please let me know what you think about this. Herb Schoenbohm. KV4FZ _ Topband Reflector Archives - http://www.contesting.com/_topband Topband Archives - Contesting Online Home<http://www.contesting.com/_topband> www.contesting.com Topband Mailing List Archives. Search String: [How to search] Display: ... _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Beverage Feed-line Noise Pickup
Herb -- I don't have Beverages, but rather pennant antennas. I think we have potential problems at both ends of the feedline and need protection at both ends. I use Fair-Rite 31-material snap-on cores at both ends, and there's a noticeable difference in the noise level if I remove either one. I suggest you check out "A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing," by Jim Brown, K9YC, which can be found at http://www.k9yc.com/RFI-Ham.pdf. I found it very helpful in understanding that problem and others, and have been able to do a lot to reduce the amount of locally-generated noise that finds its way into the shack. Hope this helps. Art Delibert KB3FJO From: Topband <topband-boun...@contesting.com> on behalf of Herbert Schoenbohm <he...@vitelcom.net> Sent: Thursday, December 1, 2016 12:06 PM To: Topband Subject: Topband: Beverage Feed-line Noise Pickup On my Beverage feed-line RG6 runs (some 200 feet) I use multi-turns a large toroid on each feed-line and the attach each coax to a grounding block and good ground rods (typical Hume Depot RG-6 variety) then on the other side of the grounding block before the coax runs about 20 feet to the Beverage Switch I have another large wound 13 turn toroid. I have since learned that I probably have all my feed-line noise suppression stuff in the wrong place and that the equipment side toroids are probably useless anyway. Now I am told that this noise pickup suppression stuff needs to be out by the actual Beverage feed and about 20-30 feet away. The reasoning is that the noise pickup by the feed-line needs to be blocked from coupling into the antenna itself. Is this true? I am starting to move the toroid-ground-toriod RG-6 "T" combos out closer to the antennas. I noticed that DX-Engineering sells an RFCC-1 box designed for Beverage coax runs but suggests it be place about 20 to 30' from the Beverage feed which has it's own separate ground rod. I bought one and before I put it out near the Beverage feed I thought I would it in place of the toroid system near the shack on one of the Beverage feedlines. However when I grounded the unit to the Beverage ground system near the shack I immediately noticed the noise floor jump up by about 10 db. I now know it is in the wrong place but this test with the DXE RFCC-1 may prove something of interest. Please correct my assumption if it is wrong: Noise pickup from long Beverage feed-lines flows back toward the Beverage feed point and then it is coupled via the feed point transformer back down the center conductor to the receiver. If this is true I will remove all toroids at the house and put them out near Beverage feed points (about 30 feet away with separate grounds based on the advice I receive back from this post. Please let me know what you think about this. Herb Schoenbohm. KV4FZ _ Topband Reflector Archives - http://www.contesting.com/_topband Topband Archives - Contesting Online Home<http://www.contesting.com/_topband> www.contesting.com Topband Mailing List Archives. Search String: [How to search] Display: ... _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Beverage Feed-line Noise Pickup
On my Beverage feed-line RG6 runs (some 200 feet) I use multi-turns a large toroid on each feed-line and the attach each coax to a grounding block and good ground rods (typical Hume Depot RG-6 variety) then on the other side of the grounding block before the coax runs about 20 feet to the Beverage Switch I have another large wound 13 turn toroid. I have since learned that I probably have all my feed-line noise suppression stuff in the wrong place and that the equipment side toroids are probably useless anyway. Now I am told that this noise pickup suppression stuff needs to be out by the actual Beverage feed and about 20-30 feet away. The reasoning is that the noise pickup by the feed-line needs to be blocked from coupling into the antenna itself. Is this true? I am starting to move the toroid-ground-toriod RG-6 "T" combos out closer to the antennas. I noticed that DX-Engineering sells an RFCC-1 box designed for Beverage coax runs but suggests it be place about 20 to 30' from the Beverage feed which has it's own separate ground rod. I bought one and before I put it out near the Beverage feed I thought I would it in place of the toroid system near the shack on one of the Beverage feedlines. However when I grounded the unit to the Beverage ground system near the shack I immediately noticed the noise floor jump up by about 10 db. I now know it is in the wrong place but this test with the DXE RFCC-1 may prove something of interest. Please correct my assumption if it is wrong: Noise pickup from long Beverage feed-lines flows back toward the Beverage feed point and then it is coupled via the feed point transformer back down the center conductor to the receiver. If this is true I will remove all toroids at the house and put them out near Beverage feed points (about 30 feet away with separate grounds based on the advice I receive back from this post. Please let me know what you think about this. Herb Schoenbohm. KV4FZ _ Topband Reflector Archives - http://www.contesting.com/_topband
