David, 1. Make sure you have a bit of standoff for the 4:1 Current Balun from the actual chimney to prevent coupling RF to the brick (they are red for a reason). 2 Make sure you provide strain relief for the ends of the wire where they attach to the post above your fence. I use surgical tubing, but you can just as easily use a bungee cord. This prevents differential movement of the post and the chimney for transferring strain on the wire to the chimney, which is only designed for wind loading, not lateral stress. 3. If the wire of the antenna is reachable by ANYONE EVER, make sure it is insulated wire. If someone touches the bare wire while you are transmitting they WILL get a serious RF burn. 4. Don't buy a dipole, make it. It is good practice, it allows you to select the wire you want to use (i.e thin and the right color insulation to not be seen, the right tensile strength to not sag, etc), and it allows you to understand cut long and trim. Buying a dipole doesn't gain you anything, because it still needs to be trimmed. If you need to borrow a solder gun, some flux paste, and 60/40 to solder the wires to the Balun, let me know. I will also let you borrow my Rig Expert Stick when you need to trim the antenna, which you will need no matter if you make or buy.
Ron KE4DRF On Fri, May 7, 2021 at 4:41 PM David Mehl via BVARC <[email protected]> wrote: > Jeffrey > > > > The Internet has multiple pages that warn that antennas can overload and > pull down a brick chimney. Other pages say small antennas are okay, but > don’t mount anything big or needing a rotor. Then again, other pages are > ‘anything goes’ on a chimney. > > > > So there is no consistent advice. Sort of like do you need to run ground > rods and wires all the way around your house. > > > > > > David > > > > David Mehl > > Houston TX USA > > > > *From:* Jeffrey Carson <[email protected]> > *Sent:* 7 May, 2021 3:16 PM > *To:* BRAZOS VALLEY AMATEUR RADIO CLUB <[email protected]> > *Cc:* MIKE BRANNAN <[email protected]>; Karl Bernard < > [email protected]>; David Mehl <[email protected]> > *Subject:* Re: [BVARC] HF Antenna Advice > > > > What "warnings" did you read about using a chimney for a mount. Never > actually heard of any myself. Is it about it not being sturdy or something > else? > > > > On Friday, May 7, 2021, 03:12:02 PM CDT, MIKE BRANNAN via BVARC < > [email protected]> wrote: > > > > > > Years ago I used steel strapping around my chimney to hold a heavy dipole > with large traps. Worked fine. Even went though several high wind events. > One removed a large portion of the roof. > > Sent from my iPhone > > > > On May 7, 2021, at 1:14 PM, Karl Bernard via BVARC <[email protected]> > wrote: > > > > David, > > > > I wouldn't think that a dipole of any kind would put too much of a strain > on your chimney. Even with the balun, that one only weighs 1.2lb (per DX > Engineering - https://www.dxengineering.com/parts/mfj-2010 > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.dxengineering.com%2Fparts%2Fmfj-2010&data=04%7C01%7C%7C75e1ae4030ed40ff131608d91194f336%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637560153693234193%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=%2FjCL7d2cg1mIvKxReyn5Yh%2FYgSRkatho9RPLrHV33uY%3D&reserved=0> > ). > > > > Since whatever you use as a mount will weigh more than the antenna, just > be sure to use a lightweight mount. > > > > Disclaimer - this only my opinion. I've never mounted an antenna on a > chimney before. > > > > Thanks, > > > > Karl > > W5KMB > > > > On Fri, May 7, 2021 at 12:43 PM David Mehl via BVARC <[email protected]> > wrote: > > BVARC Club > > > > I am a new ham and a club member since I passed my Tech last August at the > BVAC testing. I have also passed both my General and Extra exam about a > month ago. I am working on setting up a HF radio for home. I have a > ‘backordered’ IC-7300 which may show up one day. In the mean time, I am > trying to plan for my HF antenna that will fit on my small lot. I think I > can run an 40-20-10-6 OCFD (*MFJ-2010) in a slope from a tree in my front > yard, with the feed point hung off a mounted on chimney, and then on to a > post above my fence in my backyard. I don’t have any trees in my backyard. > Instead I have power lines across the back of the lot that I have to avoid. > > > > I keep reading various comments and warnings about using a chimney for a > mount. My chimney is in good repair, having been inspected and repaired > during my home rebuilt after being flooded during Harvey. > > > > Is the center of the OCFD a light enough load to consider using my chimney > as a center mount? Is there a right way to do that? Or should I ‘bite the > bullet’ and setup a pole beside the chimney? > > > > Any other antenna advice for a novice? > > > > Thanks > > > > AI5DK > > David > > David Mehl / Houston Texas USA / [email protected] > > > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmail.bvarc.org%2Fmailman%2Flistinfo%2Fbvarc_bvarc.org&data=04%7C01%7C%7C75e1ae4030ed40ff131608d91194f336%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637560153693244149%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=9CHCPyF1ITjjhj%2Ba7Co%2BU62d0hw2iqTuPFq3lJYVAjo%3D&reserved=0> > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.mail-archive.com%2Fbvarc%40bvarc.org%2F&data=04%7C01%7C%7C75e1ae4030ed40ff131608d91194f336%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637560153693244149%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=7ON38yx7sEYCxUycWBa4MaCmOAw3e%2BgVW%2BXnnWJArEc%3D&reserved=0> > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ > > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > <https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmail.bvarc.org%2Fmailman%2Flistinfo%2Fbvarc_bvarc.org&data=04%7C01%7C%7C75e1ae4030ed40ff131608d91194f336%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637560153693254102%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=m1k6bXB9m%2BAkp7aTcrVG6YxeVuKA3r6ECp2GBIU4Clc%3D&reserved=0> > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ > > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.mail-archive.com%2Fbvarc%40bvarc.org%2F&data=04%7C01%7C%7C75e1ae4030ed40ff131608d91194f336%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637560153693254102%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=CC5J9JfUdHRZA8rEQ1fpl1%2FKgHKg1Go%2FPqTXcVjSSXA%3D&reserved=0> > ________________________________________________ > Brazos Valley Amateur Radio Club > > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > Publicly available archives are available here: > https://www.mail-archive.com/[email protected]/ >
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