For six years my main home aerial has been 21 metres of horizontal wire, fed one-sixth of the length from the house end via a 4:1 matching transformer. It is easily matched and near-resonant on the 40, 20, 15, 10 and 6 m bands and has yielded good DX on all five bands. It is about 8 metres above ground. It is also remarkably good for local traffic on 160 m, but only fails miserably on 80 m. Not bad for less than £30 UK (homebrew, of course - no commercial stuff here).
Yes, that's a great choice of lengths, and makes a good antenna for 40, 20, 15 and 10 with 6 thrown in for good measure. I use something very similar (18% / 82% split) for portable use.
Hi Peter, enjoyed the video. I've been experimenting with something similar the past couple months but using non-resonant lengths. Kind of a random wire OCF vertical. All the best and 73, Walt K4OGO
Looking good Peter and interested to find out more 👍.... Can't say I have tried an OCF vertical. I have made vertical EFHW, 1/4 wave and "random" wire with 9:1 UNUN, sleeeved dipole and zeppelin. As you say, no radials or counterpoise can definitely be an advantage. 😀 Could you perhaps argue that an EFHW is just an extreme version of the OCF dipole?
I built a similar antenna on 20m and it worked very well. I found that I had a lot of common mode current and needed a choke 1:1 unun to suppress it. It was a solid performer. Charlie KM4ZZ
Dear Peter, nearly missed your video, ...! What a wonderfull small antenna, with such a remarkable good preformance, you suggested here! If I should double all the 'lenghths', around the antenna and the 'pole', would it be possible to 'work' also the 'lower bands,' with that longer 'type' of antenna? - Maybe with better efficiency? - Feeding-point at 1,6m height will be no problem anyway. I have an 12m fiber-pole, and it looks like it will 'hold the wire without any doubt, ... ! I am looking not for 160m! 40 and 60m, maybe 80m will do it also, ... ! (Sun-spots will fade away in the comming future, not yet and tomorrow, but in 4 or 5 years, the situiation will be an other one!) Perhaps, I have to 'double' the amount of the inductance and capacitance, in the 'antenna-L-coppler', ... ? What will happened with the 'higher-bands'? Are theese bands going 'bad' then? What's with the 6m-band? (We are able to do also 4m in DL/LX/EU !) This is also an important question for me, not only for the 'longer pole', also for the 'shorter one' with only 6,4m height. Please tell me, what you think about my suggestion. Sorry for my bad English, it is not my native tounge, ... ! 72/73 de Markus - db9pz - (located in JN39fq ; 3miles/5km east of LX)
Yes it should work on lower frequency bands with a longer length. Though radiation patterns will change on the higher HF bands especially. Which might not necessarily be favourable if you want low angles.
This sounds good, and definitely needs to be tried out. I'd be more impresssed, however, if you had made proper SWR measurements with a VNA, rather than with the much less accurate "SWR meter" in the FT 817. I find it rather suspect that you kept getting low SWR on all the bands you tried - including 17m and 12m where a horizontal OCFD with a 12% / 88% lengths split would show very high SWR. It's often said that a dummy load has a perfect 1:1 SWR, but it's not exactly a great antenna.
I don't care about VSWR. I always use a coupler. Provided the FT-817 is happy then so am I. Other factors are more important for antenna efficiency for your desired frequency and path.
@@vk3ye "Other factors are more important for antenna efficiency for your desired frequency and path" Certainly, and those factors include not having the feedpoint too close to the ground, and taking care of common-mode currents on the coax feeder. I'm saying the SWR meter on the FT-817 is not really accurate enough to make the conclusions you're making AND that you seem to be unaware of how exactly the natural SWR minima and maxima of such an antenna change with frequency. For your configuration, 17m and 12m should be unattainable, yet you claim to be able to tune easily on those bands. Something in your setup is clearly not working correctly.
I think, cw would be better for testing than ft8. With ft8 you can reach the whole world. But for "real" communikation, as cw, the maximum distance is far less.
Guessing it would be in the order of several hundred ohms on 21 MHz, different on other frequencies. The LC unit is for sale in the sense that all parts to build one are available from Jaycar.
Feeding right at the bottom will require some form of impedance transformer to match the cable to the very high impedance of an end-fed half wave. A choke would be desirable. But you won't get multiband coverage like I did with the antenna coupler.
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@@vk3ye ok, thanks. I was thinking of the open sleeve (?) vertical dipole which is fed at the bottom but the actual feedpoint is in the middle. And whether your idea can be applied to this design to get more bands.
I have done some experiments with vertical antennas fed by matching networks, mostly EFHW. When you connect near the ground, the common moles are satisfied and there is very little common mode current. Also with these multiband antennas there is such a thing as the antenna being too long. Interference can come from lower bands and cause intermodulation on 6 & 10m.
@@antennafarmer7380 There is indeed such a thing about antennas being too long if it means a radiation pattern you don't want eg lots of high angle lobes. But intermodulation and interference have nothing to do with the antenna. If you suffer it then the problems are with your equipment - not the antenna.
