Hi All, A couple of thoughts:
I used an aluminum powder filled version of Permatex or similar anti-seize compound the last time I put up an aluminum tower (Heights or Universal). No continuity problems. Also with a rigid galvanized free-standing tower (Probably American Tower or Pyrod) I used zinc filled anti-seize compound on the face of the flanges between sections. No conductivity problems for the 16 years it was up with a shunt feed for 160 meters. The AB-577 is probably resonant near 3.5 MHz with the C-3 antenna on top if one wants to shunt feed it for 80 or 75 meters. So, I vote for an inverted-L for 160 either supported from the top of the mast or from a separate tree. GL & 73, George, K8GG > Hi Pete, > > Good question. I haven't done it with any of my three AB-577s, but I've > seen recommendations from others that the sections be electrically bonded. > > I'm not sure about the case for that. I just measured continuity on the > flat portion of a spare tube and it showed zero ohms. If the contact areas > are clean when the mast is assembled, they should make good contact with > zero resistance. The clamp should act to keep the flat areas in contact, > as should the downward pressure from the guys. I guess it may be possible > that dirt carried by rain water might seep into the clamp and get between > the sections as they rock back and forth in the wind, even if it's just by > nanometers. > > If you buy that possibility, I think it can be overcome pretty easily by > attaching right-angle tabs to the top and bottom of each section with > screws/nuts, and running a section of copper strap between them, also > secured with screws and nuts, or perhaps you can find some sort of clamp > that would let you quickly connect/disconnect the strap as you raise/lower > the mast. > > Hope this helps. > > 73, Dick WC1M > > -----Original Message----- > From: N4ZR <[email protected]> > Sent: Monday, October 1, 2018 11:48 AM > To: topband reflector <[email protected]> > Subject: Topband: Shunt feeding AB-577/621 > > I have an AB-577 with a C-3E on top, and am interested in the possibility > of shunt-feeding it for 160 - 100 watts only. Anyone have any experience > with doing this? Are the section-to-section joints adequately conductive? > I would plan to use an omega match, because I'm guessing it would be well > short of a quarter wave. > > My other option is an inverted L. Should I maybe just go ahead with that? > > -- > > 73, Pete N4ZR > Check out the Reverse Beacon Network > at <http://reversebeacon.net>, now > spotting RTTY activity worldwide. > For spots, please use your favorite > "retail" DX cluster. > > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
