2m big wheel arrives

My 2m big wheel antenna has arrived. I now need to find a kind local to help erect it. It needs 2 brackets fixing and the coax attaching.

In the past this would have been trivial for me, but sadly not in my present state of health. Anything above head height and I feel giddy. Work on ladders is impossible. I hate being like this.

2m big wheel

Well, I have ordered one (yes I know I could have made one although not in my present state) so I hope this can be erected in the next few weeks, although I shall need help to do this as I am no good on ladders in my current poor state of health. It would be good if I could get a long wire erected at the same time for LF/MF use, although this could wait. At this time I am going for a single big-wheel rather than a stack.

I have decided against buying a 70cm big wheel at the same time as this would require a new length of low loss cable too. I also checked my existing low loss cable and this seems in good condition, so it will be reused. I may make my combined 2m/70cm antenna into a portable antenna when I have found out why the VSWR is poor.

See https://sites.google.com/site/g3xbmqrp3/antennas/bigwheel .

Big wheel antennas

Next winter I want to replace my hand rotated beams for 70cm and 2m with a big wheel stack for either 2m or 70cm. I was going to erect a 2m big wheel stack (of 2) but looking at the logs it may better to erect one for 70cm which is the more interesting band.

2 big wheels, suitably stacked, should give about 5dBd gain horizontal and need no turning. This is not far off the gain from my 5el yagi in the best direction.  Quite often I work stations off the direction of maximum gain. For my kind of operation (mainly UKAC contests and beacon monitoring) I think a big wheel is well suited.

70cm big wheel stacks are a lot smaller than the 2m versions. The stacking distance is smaller too. Commercial big wheels are available from Wimo in Germany.

See http://www.wimo.de/big-wheel-antennas_e.html .

Big wheel antenna

Big Wheel for 2m

A good 2m antenna for horizontal polarisation is the big wheel. Quite a few beacons use these as they require no rotator and a couple of these stacked give about 5dBd gain horizontally. So, these would be ideal for fixed station use. They would suit me well for UKAC 2m contests and general 2m SSB/CW use. I know that my 3 el, hand rotated, beam has about the same gain.  One big wheel alone is better than a halo, but two suitably phased would be better than a small beam.

See https://sites.google.com/site/g3xbmqrp3/antennas/bigwheel .

ON0VHF 2m beacon 144.418MHz

The 2m beacon ON0VHF seems to be copyable at all times at a distance of just over 350km.  It is located just the far side of Brussels.

Imagine my surprise when I found out it is only running 15W to a single big wheel antenna with a gain of around just 3dBi. At one time I was considering a stacked pair of big wheel antennas here. In theory, properly phased, a pair of big wheels should give omni-directional horizontal gain of around 5dBd, which is similar to a small beam without having to turn it.

2m big wheel antennas on 70cms?

Just wondering if anyone has checked what a horizontally polarised 2m big-wheel antenna looks like (gain, match, directivity, polarisation) on 70cms?

At the new QTH, the most likely antenna on the apex of the bungalow will be a 2m big-wheel (for 2m datamodes, SSB, CW) with a V2000 fitted above it (for 6m Es, 2m and 70cm FM) with suitable spacing between them (>1.3m). It would be useful if the big-wheel behaved well as a half decent horizontal omni on 70cms too so it could be used in UKAC contests.

More big wheels and turnstiles

When looking around for possible homebrew designs I saw an article that appeared in QST back in 2008.  Looking at this approach I am not convinced it is easier than the conventional big wheel design though. See http://radio-amador.net/pipermail/cluster/attachments/20100107/a2f81f3e/AntenaHPOD.pdf . 

A design for a 70cm big wheel, designed to be used with a beacon, is available at http://www.qsl.net/dl4mea/antennas/bigw.htm .

The turnstile design on the EA4EOZ website

Another simple approach to a VHF or UHF omni-directional horizontally polarised antenna is the simple turnstile (a pair of phased cross dipoles that produce an almost 360 degree clean radiation pattern with about 0.9dBd loss only). These can be stacked to produce gain, as with the big wheel.

Overall, the conventional big wheel design is my favoured approach for 2m and 70cm. Whether I make my own or buy a Wimo version remains to be seen.

Big wheel antennas?

www.wimo.com big wheel

When I move to my new (higher) QTH on top of our local East Anglian "hill" next year I'll have to give some thought to what VHF/UHF antennas to erect for horizontal SSB/CW/digital DXing. I could go for a decent set of beams and a rotator or I could go for an alternative approach and erect a stack of big wheel antennas for 2m and 70cm. A single big wheel has a horizontal gain of around 2-3dB over a dipole but a couple will give almost 5dBd, which is similar to an HB9CV beam but without the hassle of a rotator and with almost 360 degree coverage.

For my sort of (occasional) 2m and 70cm DXing the big wheel may be a suitable solution. I have around 6 months to sort this out, so no rush, but I'd value inputs from people on this. Have you used big wheels? How effective were they?

Incidentally, even from my old QTH I've worked all sorts of decent VHF DX with just a halo and a few watts QRP in contests, so a lot depends on how prepared one is to wait for lifts or big contest stations to work. Clearly if the aim is to work 600-700km under flat band conditions then 100W and a largish beam are almost essential. I'm not entirely ruling such a station out of the question, but it would be a big change from my usual QRP, so pretty unlikely.

Rotators or big wheels

There was a time when a small rotator capable of turning a modest 2m yagi could be bought for around £40 but there appears to be little available now below £300. The low cost Yaesu rotator (G250?) appears to be unavailable now.  I was thinking about erecting small beams for 6m, 2m and 70cm and was wondering about suitable rotators, but am rather put off by the costs.

A better alternative may be a big wheel antenna with around 3dBd gain omnidirectional, or more if two are stacked. 5dBd is at least as much gain as an HB9CV without the worry of a rotator.