Dick, I've been experimenting with, and developing, the Hexbeam for a couple of years now. It certainly outperforms other small HF beams I've owned such as the Cushcraft MA5B and and the Butternut HF
Dan, You got there before me! This design cannot work satisfactorily as shown. Not only are the "integral stubs" very lossy, as you point out, but the Reflector is totally "closed" (inner and outer s
All that Dan says, plus...... ...... the Reflector has the Inner and Braid shorted at both ends. There is no way for differential-mode currents to be excited in the Reflector coax so there can be no
Randy, The #16 "silky" seems to work well on the Hexbeam, which is a very similar application. If you end up using anything with insulation, remember you'll need to adjust dimensions to account for t
Joe, Sorry to "nit pick", but if your formula is correct and the constant is 0.5, shouldn't the loss be 0.57dB? It makes a big difference if you have several connectors in the chain. 73, Steve G3TXQ
Is there another piece missing from this jigsaw - the length of the feedline? Taking Jim's figure for Rr of 35 Ohms, we get a VSWR of 2.1 in a 75 Ohm system. BUT if the feedline were an electrical qu
Patrick, As others have said, it mostly comes down to personal choice about the interface. The underlying "calculating engines" are the same. I'd suggest you get hold of MMANA and the free version of
Gordon, There's a couple of pages of information about antenna height on my web site that you might find interesting, particularly the second page. They are part of the Hexbeam section, but the data
When I'm making Far Field measurements on an HF antenna - for example plotting its azimuth pattern by rotating it whilst measuring relative field strength at a remote point - how far away do I need t
Thanks to everyone for their advice. It sounds as if I should be OK to make 20m thru 10m measurements on HF minibeams at a range of 150ft or more? Steve ______________________________________________
I owned an MA5B for several years and was happy with it. Up until then I'd only ever used dipole/doublet antennas and it was a definite "step up" in performance. It seemed well constructed and went t
Tony, With a ladder-line / tuner arrangement you don't need to worry about cutting the antenna for a particular part of the band. But you do need to worry about whether the antenna/ladder-line combin
Be aware that there are some "extreme" cases where minimum VSWR and Resonance do not occur at **exactly** the same frequency. For example, if I take a 34ft folded dipole, and am silly enough to feed
Gerald, I agree that for most "normal" situations minimum VSWR and resonance are coincident. But I have given one example, and there are others, where they are not. The values I quoted were taken fro
Tom, A quarter-wave vertical over a perfect ground would be about 35 Ohms, not 50-75 Ohms. But 10 Ohms still looks odd. Can you post a copy of the EZNEC file somewhere so that we can take a look? 73,
Tom, Certainly a major flaw with your existing model is the segmentation. In some instances you had adjacent segments with a 30:1 ratio of length. You also need shorter segment lengths than you have
Peter, I hope you didn't fall into the trap of just comparing the optimum take-off angles. It's quite possible for a dipole with a higher take-off angle to be better than a vertical with a low take-o
Here's another example. 40m half-wave dipole at 40ft vs 45ft monople: http://www.karinya.net/g3txq/dipole_vs_monopole2.png Notice that the dipole "take-off angle" is 51 degrees compared to the monopo
Peter, "In all cases the dipole radiated at a slightly higher angle than the vertical, which is why the vertical is a better choice, sometimes, than the dipole for low band DXing." Steve G3TXQ ______