I’ve been thinking about how to make a very portable beam antenna for VHF/UHF and possibly satellite OPS and the idea of an “umbrella hexabeam” came up. I.e a hexabeam made with thin flexible wire that could collapse/open in the same was as an umbrella. Has anyone seen this before? I was hoping to minimize the number of design iterations but I can’t find any designs for hexabeams this small. Although to be fair, because it is so small the iterations would be particularly easy! Also, the hexabeam makes tracking overhead satellites really easy, just point the shaft orthogonal to the plane of the orbit and spin about that axis (True this won’t be prefect and wont’ work well for passes with low peak elevation)
That’s an interesting idea. I don’t see why it shouldn’t work. Ideally the design should be easily tilted so it can operate with vertical polarisation as well. Or even both at the same time with two hexbeams which might be useful for satellite QSOs.
Honestly, that’s what I’m asking the community as an antenna dilettante! There are reports that hexabeams match 3 element yagi’s in gain and F/B but aren’t as good as the standard 11 element UHF on dual yagi’s like the Arrow. But for something that folds up and could be very packable I’d be willing to take a bit of a hit.
I experimented, briefly, with the concept of a portable monoband hexbeam during the 12 metres challenge, but it didn’t turn into anything usable on a summit. A simple GP-vertical was much easier to deploy and use.
For 6 or 4 metres the geometry of a hexbeam might be easier to manage on a summit, but by the time you get up to 2 metres or 70 cms you might as well go with a portable yagi.
This all makes sense, thanks for the feedback. Since it’s such a simple design, I think I’ll likely throw together a simple wire planar mono-band test system mainly because I am curious to see how it works.
Rather than a HexBeam approach for strength while being small I used to use a MOXON. Par electronics in the states make these commercially or you can build yourself. These are single band antennas and made for 6m, 2m. Theoretically it should be possible to build one for 70cm as well.
Working “outside of the box” - what about a transmitting magnetic loop antenna. Box73 in Germany sell one for €14 that is etched on a PC Board for 2m. Mine actually sits on top of the HT is directional and is trimmed with a small capacitor to where you want on the band. The big advantage is that it is VERY small (and cheap). https://www.box73.de/product_info.php?products_id=4014
73 Ed DD5LP
The Moxon looks like a nice variation on the theme and definitely worth investigating. I may mock one up to compare to hexabeam approach.
I like mag loops (it is my goto HF antenna when I’m going to be activating next to a radio tower due to the natural out-of-band rejection) but not particularly well suited to satellite work which part of what is getting me thinking along these lines. I have a roll-up slim jim that I currently use and thinking about something compact to point skywards!
Doing a bit more research it does look like the moxon outperforms the hexabeam (gain, F/B and SWR) at the expense of a bit of size (A Tale of 4 Beams). The moxon also has a rear null which is nice for DF applications.
There are also dual band “moxon+yagi” designs out there that seem to perform well with a common driven element. Small Duoband-Antenna
On HF, so I presume also on VHF/UHF there are designs to “nest” MOXON antennas as long as the bands are far enough apart.So a nest of 6m, 2m & 70cm may be possible. Multi-Banding the Moxon Rectangle
If you want more gain from a single band antenna, there are also 3 element Moxons such as this one: 3 element moxon