Hi all,
Since the trip to YJ0X, I had been contemplating building a VDA for 6m.
The one we used for 12m was superb and a compact directional antenna for
6m would have been "magic".
If you wish to build one visit http://www.f4bkv.net/antenna-vda.html and
you'll see there is no design for 6m, so I halved the 12m one and
trimmed as necessary to find the following specs (made with 1.5mm
insulated appliance wire with a VF of approx 94%).
Spacing: 1.0m
Boom height: 1.95m
Half Driven: 1.27m
Half Refl: 1.35m
Driven spacing: 0.13m
Refl spacing: 0.12m
This antenna could easily be made with a 4m length of 32 or 40mm PVC
pipe as a mast and a 20mm PVC pipe as the spreader.
Have fun!
Paul
VDA Antenna For 6m
Re: VDA Antenna For 6m
From Vincent's VDA design notes:
If you do not plan to install your antenna near the sea water, then forget it and look for some other antenna designs. The VDA is performant ONLY near the sea water, and with the sea in the path to the DX.
This would rule out many/most opportunities methinks...especially if scaled for 6m.
If you do not plan to install your antenna near the sea water, then forget it and look for some other antenna designs. The VDA is performant ONLY near the sea water, and with the sea in the path to the DX.
This would rule out many/most opportunities methinks...especially if scaled for 6m.
73
Andy VK6OX
If you can't explain it simply, you don't understand it well enough. Albert Einstein
Andy VK6OX
If you can't explain it simply, you don't understand it well enough. Albert Einstein
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ZL4PW
Re: VDA Antenna For 6m
Hi Vincent,
The proof of the pudding is in the eating..
Between the antenna an the US and to JA were many kms of land... the antenna worked superbly. On the sea-paths to Southern Africa, South America and LP Europe it exceeded expectations.
Nothing ventured, nothing gained.
Regards,
Paul
The proof of the pudding is in the eating..
Between the antenna an the US and to JA were many kms of land... the antenna worked superbly. On the sea-paths to Southern Africa, South America and LP Europe it exceeded expectations.
Nothing ventured, nothing gained.
Regards,
Paul
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VK4WDM
Re: VDA Antenna For 6m
Hi Paul
How DARE you flaunt yet another wire antenna in front of a TAWAN like me, now I will have to go back into therapy
Seriously though, in these days when many are on restricted budgets we should be experimenting more with simple low cost antennas such as this. I'd say go ahead and make one and suck and see.
Most verticals work better near water but that does not mean, as you have already proved, that they are useless away from water. The GAP series antennas, from memory, consist of vertical dipoles.
It would be very easy to mount elements for say, 6, 10, and 12m on the same mast making it a very good portable antenna.
73
Wayne VK4WDM
How DARE you flaunt yet another wire antenna in front of a TAWAN like me, now I will have to go back into therapy
Seriously though, in these days when many are on restricted budgets we should be experimenting more with simple low cost antennas such as this. I'd say go ahead and make one and suck and see.
Most verticals work better near water but that does not mean, as you have already proved, that they are useless away from water. The GAP series antennas, from memory, consist of vertical dipoles.
It would be very easy to mount elements for say, 6, 10, and 12m on the same mast making it a very good portable antenna.
73
Wayne VK4WDM
Re: VDA Antenna For 6m
A full size loop antenna on 6M would in my view may be a better option.
The loop would be directional, provide gain and perhaps more importantly be electrically quieter if set up to be horizontally polarised (fed at base).
Total wire length would be about the same. The Loop would be slightly wider than a VDA but it would have less height.
The loop would be directional, provide gain and perhaps more importantly be electrically quieter if set up to be horizontally polarised (fed at base).
Total wire length would be about the same. The Loop would be slightly wider than a VDA but it would have less height.
73s
Igor
VK6ZFG
Igor
VK6ZFG
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ZL4PW
Re: VDA Antenna For 6m
Hi Igor,
We did use a 6m full wire loop with great success. I would assume the VDA would be more directional and easier to put up. We hung the loop from a tree by one corner with a PVC conduit spreader. Would have been good to have a VDA for 6m to make a comparison.
The VDA is from the Moxon family and reportedly outperforms the latter. Used on many major DXpeds these days.
Cheers,
Paul
We did use a 6m full wire loop with great success. I would assume the VDA would be more directional and easier to put up. We hung the loop from a tree by one corner with a PVC conduit spreader. Would have been good to have a VDA for 6m to make a comparison.
The VDA is from the Moxon family and reportedly outperforms the latter. Used on many major DXpeds these days.
Cheers,
Paul
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VK2KPK
Re: VDA Antenna For 6m
If you plot boom height against frequency (band) you will notice that it is not linear.ZL4PW wrote:
Boom height: 1.95m
Paul
My extrapolated graph indicates that boom height should be about 3.27m.
I have not built it so cannot confirm.
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ZL4PW
Re: VDA Antenna For 6m
Hi, I asked Vincent for either his calculations/formula or for a 6m design but didn't get a reply. It would be interesting to try it at the two heights. Cheers, Paul