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#1
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Here's one for all our experts and gurus out the
Consider a 140' dipole up at 40' height. Used on 160-10m Other scenario is a 50' top loaded vertical, with 4 radials, 70' each, used on 160-20m. The question is which antenna gives us more radiated energy going out in useful directions? A fair amount of the dipole energy goes into the ground. Another big chunk goes into cloud warming. That leaves some energy going out at elevations which are useful to us. The vertical doesn't do much cloud warming. It does have some energy going to ground, but probably less than the dipole. However, it doesn't have nearly as much radiating surface as the dipole has. But, being top loaded, it does tend to get the current node maxed on the available vertical (radiating) surface. So, holding power input constant, etc, which antenna gives us the more useable rf energy output for hamming on 160-20m? |
#2
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RB wrote:
The question is which antenna gives us more radiated energy going out in useful directions? Please define what "useful directions" personally means to you. I prefer NVIS for "useful directions". -- 73, Cecil http://www.qsl.net/w5dxp |
#3
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If you can answer which is best: Mac truck or Corvette?
We can answer your question. It depends on lot of things, what you want to do with it (who to communicate with, where, when, what band) etc. You need to consider propagation modes and nuances Know the antenna patterns for particular band Antennas are a fascinating subject and there is a lot of information in the literature and worth studying if one is serious about operating on the bands. Knowing that, one could do good job in selecting or designing the antennas for particular task. Yuri, K3BU.us |
#4
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If we get rid of cloud warming angles of elevation, I guess we're left with
NVIS. I think that's what I would call a useful direction. |
#5
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RB wrote:
If we get rid of cloud warming angles of elevation, I guess we're left with NVIS. I think that's what I would call a useful direction. NVIS *IS* cloud warming angles of elevation. Those are the ones I prefer for my type of operation. Who wants to talk to strangers who don't speak Texan? :-) -- 73, Cecil http://www.qsl.net/w5dxp |
#6
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Well, I'm still getting tripped up in my terms. Not doing too well, here.
What I'm looking for is max low angle radiation comparison of the two. |
#7
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"RB" wrote in message
... Well, I'm still getting tripped up in my terms. Not doing too well, here. What I'm looking for is max low angle radiation comparison of the two. The vertical, should have a far better low angle performance, although four radials is probably inadequate to minimize ground absorbtion. The inclusion of a loading coil does little or nothing to effect the radiation efficiency. Frank |
#8
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Frank wrote:
"RB" wrote in message ... Well, I'm still getting tripped up in my terms. Not doing too well, here. What I'm looking for is max low angle radiation comparison of the two. The vertical, should have a far better low angle performance, although four radials is probably inadequate to minimize ground absorbtion. Better to s that the vertical will put out more of it's energy at low angles. That makes a difference. Another thing to consider is that the vertical will take a whole lot longer to install than the dipole. Those radials can be a real pain in the back! The way my thinking has been shifting recently, I would suggest that people - a lot of people - think of the radiation pattern of an antenna as some sort of narrow blob that shoots off the thing at the "maximum angle". Trouble is, all antennas radiate at all angles. Some just better than others. Before condemning a dipole as not usable for DX because of its radiation angle, we should probably compare it to the angle of that vertical. Then look at just how many db difference there is between the two (all else being equal). And of course, as I have been finding out, which one does best at any given moment (let's define best as the highest signal level at the receiver) is going to change from moment to moment. I haven't gone to transmitting differences yet - 73 de Mike KB3EIA - The inclusion of a loading coil does little or nothing to effect the radiation efficiency. |
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