All, I don't think anybody was questioning the fact that the OCF dipole "works." If you haven't read it, I encourage you to borrow or buy a copy of the book Array of Light by Tom Schiller, N6BT, and read the chapter "Everything Works." The point of the essay is that you can make QSOs (even DX QSOs from W6) with a 100-watt lightbulb "antenna" at the end of a piece of coax. Compared to that, the OCF will certainly allow you to work stations, especially when conditions are good!
However, the OCF dipole is in a class of antennas commonly used by amateurs that is known to invite problems (e.g., RF in the shack, common mode noise, and so forth) that are easily mitigated by using a different type of antenna and feed arrangement. That does not mean that people in urban areas with relatively high noise floors or those who run low power might not be perfectly happy with them. It's all about the design goals you have for your station. If someone notices that they've been experiencing one of the symptoms of imbalance listed above, it's only natural to suggest that the antenna might be the culprit. That is all. I should probably go play some more in the NAQP while my toddler is still asleep... 73, --Ethan, K8GU/3. On Sat, Jan 11, 2014 at 2:10 PM, Stephen Roberts <steve...@shoreham.net> wrote: > I also use the 7 band Buckmaster OCF antenna. My config is the long leg is > East/West and 80' on one end and about 50 on the other (also sloping > property). The short leg is at a right angle and is about 50' on one end and > probably 30 on the other. It's fed with about 30' of coax. > > It's a fantastic antenna and I can work coast to coast QRP. It also works DX > nicely and I've worked Antarctica, NZ, etc. I think I'm up to 185 countries > now QRP. > > Steve > W1SFR > Kx3helper.com > > Sent from my iPad > >> On Jan 11, 2014, at 1:50 PM, Barry LaZar <k3...@comcast.net> wrote: >> >> Doug, >> Nice write up. >> Other Readers, >> I'd like to make a comment about the antenna as I know more than just a >> little about the things. An off center fed, OCF, dipole is not a magic >> antenna as some hams have come to believe. They are just a good wire antenna >> that is fed in a way to make them appear to have a 50 Ohm impedance. They >> are based on the 1/2 wave dipole which only has a workable impedance at 1/2 >> wave. At even multiples of a 1/2 wave, the antenna exhibits a high >> impendance which most radios do not like. So, way back in radio history a >> smart guy said if I don't feed the dipole in the center I can find a spot >> that looks like 300 Ohms and use a transformer to make it look like 50 Ohms >> over several bands. When he invented that antenna, the only odd band was 15 >> meters. What that meant was that if you created an 80 meter OCF dipole, you >> could use it on 40, 20, and 10 meters, without a tuner. >> >> The basic 1/2 wave dipole antenna can be awesome if hung up at some >> reasonable height. When fed in the center it is going to have a very high >> SWR, which means you need to be careful of transmission line loss and have >> some way to deal with the SWR. Open wire feeders handle the loss issue and a >> very good tuner does the rest. Or you go to the OCF dipole and use a 6:1 >> CURRENT balun or balun and line isolator. >> >> When a dipole is operated at multiples of a 1/2 wave you can actually >> develops gain in the plane of the antenna. How much gain and lobe direction >> is a function of how many 1/2 waves the antenna is. >> >> Those of you who want a good basic antenna and don't want to spent a lot >> and can get it up about 30-35 feet or higher go for the OCF dipole. I think >> you'll be happy. I have one up in my yard at about 40' on one end and about >> 35 on the other( it has to do with the slope of the land) and, as Doug, I >> work out everywhere. There are several sources for the basic OCF antenna and >> a source for a variant that I run. However, building one is a snap. Just go >> to Home Depot and buy 135' of #12 stranded insolated house wire ( color is >> unimportant ) have it cut such that the cut is about a 1/3 of the way off an >> end. Pick up some insulators at a hamfest and order either a 4:1 or 6:1 >> CURRENT balun. feed the beast with some low loss or reasonable loss cable, >> and then sit back and have fun. I would expect DXCC in 30 days, band >> conditions being good. >> >> Some final comments. I use #12 insulated, stranded wire just for the >> extra strength. I don't want to be puting up a new antenna every time we >> have high winds or ice. You could use #14 which most use, but like I said I >> don't want to have to re-install my antenna. You will need an antenna tuner, >> but that is OK as you will now be able to use the antenna on all bands >> 80-10. Lastly, if you don't have 135' feed of horizontal space you could >> bend the ends down to fit if it represents a minor portion of the antenna Or >> you could build a 40 meter version using 66' of wire and just not work 80 >> effectively; I can actually get mine to tune on 80, but it isn't great. >> >> 73, >> Barry >> K3NDM >> >> >> >> >> >>> On 1/11/2014 12:34 PM, Doug Ellmore Sr. wrote: >>> I saw some discussions on OCFS. I thought I would share my setup. >>> >>> I worked 160+ countries with a Buckmaster 8 band OCF QRP. K3NDM and N3HU >>> have observed its operation with my former ICOM 703, K3 and KX3. >>> >>> I think Buckmaster uses a 6:1 balun. I have my feedpoint at the peak of my >>> house about 34' fed with 60' LMR400. The feedline drops down the roof 45 >>> deg then perpindicular to the ground. It is connected to a static arrestor >>> before being fed back up to the 2nd floor shack. The long leg is supported >>> by a 14' 4x4 support north of my house but far enough away with a rope the >>> the end is 18-20' above the ground. The short leg is supported by a tree >>> up ~20' up SSE of the house. >>> >>> I used the internal tuner to tweak swr, but have also used the kx3 & >>> SB-200 to get 200 watts with no tuner with no problems. >>> >>> Check the specs on the Buckmaster, it might help those trying the OCF setup. >>> >>> A north to south orientation seems to help me work good dx from Maryland. >>> >>> 73, >>> >>> Doug, NA1DX >>> ______________________________________________________________ >>> 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 >> >> ______________________________________________________________ >> 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 > ______________________________________________________________ > 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 -- http://www.k8gu.com/ Repair. 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