Posts Tagged ‘big wheel’
2m big-wheel – 3dBd gain without rotating
Since its erection yesterday in its proper home by David G0LRD all seems to be working well.
A quick check this morning and I am able to copy the Kent, Dutch and Belgium beacons on 2m and GB3LEU (NW of Leicester) beacon on 70cm with the FT817 and 2m big-wheel. This is a single 2m big-wheel (not a stack) from Wimo in Germany.
It has 3dBd horizontal gain and is omni-directional. It is an ideal SSB/CW/data antenna for casual operators like me. “Real” operators would use it and a beam: the big-wheel to watch all 360 degrees and a big gainy beam to pounce in the choice direction. Being one who does not take the hobby too seriously just the big-wheel suits me and my style of operating! I did not look for other beacons. It is nice not having to worry about a beam and rotator.
I have still to try this antenna (and feeder) as an HF vertical via my ATU. It should work on at least some HF bands.
70cm contest using a 2m big wheel
|Stations worked on 70cm tonight with 5W and a 2m big-wheel omni|
This evening was the September 70cm leg of the RSGB’s UKAC contest, so I decided to give it a go with my 2m big-wheel and 5W SSB. The match on 70cms was very good, but I had no idea how it would actually work. Well, the answer is “very well” as you can see by the stations worked. Best DX was 182km. To say I was pleased is an under-statement! I shall be able to use this antenna again in 70cm contests. I was also able to copy the new beacon NW of Leicester GB3LEU which was pretty good copy on 432.490MHz.
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.
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.