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Jason,
What you are talking about is not a true LongWire Antenna, but a most likely a "Random" Wire Antenna. The best advice about a Random Wire antenna is for what every Horizontal Length that you can put up: Try to have it elevated (height) at 1/3 that Length. The result will be an Omni-Directional Antenna. That will allow you to receive signals from all directions. Take the time to read about the Low Noise Antenna design by John Doty. http://groups.yahoo.com/group/SWL-AM...enna/message/2 However, if you are talking about an Antenna . . . - That is over 579 Foot Long . . . - - The that is Truely a Different Question ? ? ? - - - Sit Down and Have a Beverage or two ! ! ! iane ~ RHF .. .. = = = =Jason = = = wrote in message ... Hello all I live in Northern Alberta Canada, and I am going to put up a long wire antenna. Should I orientate it in any specific direction, or just string it up ? Thanks, Jason .. |
Gregg wrote: Behold, Dale Parfitt signalled from keyed 4-1000A filament: Gregg wrote: Unless the antenna is 1/2 wave above a prfectly conducting ground or counterpoise, it really won't matter because it won't be directional. Antenna theory, and NEC modeling radically disagree with this- How many antennas do you want to see that are not 1/2 wave above a perfect ground and yet show outstanding directionality? W4OP |
In canada that will soon be against the law, one must over look
orientation because they were made that way. |
Jason wrote in
: Hello all I live in Northern Alberta Canada, and I am going to put up a long wire antenna. Should I orientate it in any specific direction, or just string it up ? Thanks, Jason It depends what you what to listen too but I go with east-west orientation. It works well. |
Behold, Dale Parfitt signalled from keyed 4-1000A filament:
Antenna theory, and NEC modeling radically disagree with this- How many antennas do you want to see that are not 1/2 wave above a perfect ground and yet show outstanding directionality? W4OP Phased arrays can be made directional. We are talking longwires here. -- Gregg *It's probably useful, even if it can't be SPICE'd* http://geek.scorpiorising.ca |
Gregg wrote: Behold, Dale Parfitt signalled from keyed 4-1000A filament: Antenna theory, and NEC modeling radically disagree with this- How many antennas do you want to see that are not 1/2 wave above a perfect ground and yet show outstanding directionality? W4OP Phased arrays can be made directional. We are talking longwires here. So am I. The higher a longwire antenna is in terms of wavelength, the better defined the nulls become; i.e. its directional characteristics are enhanced. Nothing magical about 1/2 wave above perfectly conducting ground. If you can read AO files, I'll be happy to send a file demonstrating this. W4OP |
Behold, Dale Parfitt signalled from keyed 4-1000A filament:
Gregg wrote: Behold, Dale Parfitt signalled from keyed 4-1000A filament: Antenna theory, and NEC modeling radically disagree with this- How many antennas do you want to see that are not 1/2 wave above a perfect ground and yet show outstanding directionality? W4OP Phased arrays can be made directional. We are talking longwires here. So am I. The higher a longwire antenna is in terms of wavelength, the better defined the nulls become; i.e. its directional characteristics are enhanced. Nothing magical about 1/2 wave above perfectly conducting ground. If you can read AO files, I'll be happy to send a file demonstrating this. W4OP Great! I learn something new every day :-) AO file? I'm sure I can apt-get something to read them (I run Linux). Fire away! geek at scorpiorising dot ca -- Gregg *It's probably useful, even if it can't be SPICE'd* http://geek.scorpiorising.ca |
Gregg wrote in message ...
Behold, Dale Parfitt signalled from keyed 4-1000A filament: Antenna theory, and NEC modeling radically disagree with this- How many antennas do you want to see that are not 1/2 wave above a perfect ground and yet show outstanding directionality? W4OP Phased arrays can be made directional. We are talking longwires here. Not at 3 mhz. A 70 ft, or even a 100 ft wire is not even close to qualifying as a longwire on 3mhz. It's just a random wire. Some of the upper HF freq's, yes, it qualifies. On 3 mhz, it's not even a full half wave. Worrying about the direction of the wire for 3 mhz use will be a waste of time overall. It will be fairly omnidirectional and will favor high angles. In fact, the maximum gain of such a wire on 3 mhz will be straight up, unless he can get it real high up. You would have to have the wire at least 120 ft in the air, to begin to lower the max gain from 90 degrees overhead. The azumith pattern of the 100 ft wire would be much like a normal dipole. A bit under 2 dbi gain in the favored direction, and broadside to the wire like a dipole. Not a big deal really. You will still hear plenty of signals off the ends. A real longwire would show gain in line with the wire. "bidirectional". Adding a terminating resister makes it fairly unidirectional. A longwire must be at least 1 wave on the freq to be used. And thats a real short longwire. Just barely is beginning to show gain off the ends instead of broadside to the wire. Most are multi waves long on the freq to be used. MK |
Gregg wrote: Behold, Dale Parfitt signalled from keyed 4-1000A filament: Gregg wrote: Behold, Dale Parfitt signalled from keyed 4-1000A filament: Antenna theory, and NEC modeling radically disagree with this- How many antennas do you want to see that are not 1/2 wave above a perfect ground and yet show outstanding directionality? W4OP Phased arrays can be made directional. We are talking longwires here. So am I. The higher a longwire antenna is in terms of wavelength, the better defined the nulls become; i.e. its directional characteristics are enhanced. Nothing magical about 1/2 wave above perfectly conducting ground. If you can read AO files, I'll be happy to send a file demonstrating this. W4OP Great! I learn something new every day :-) AO file? I'm sure I can apt-get something to read them (I run Linux). Fire away! geek at scorpiorising dot ca Hi Gregg, You will need any version of Antenna Optimizer. Alternatively, I can probably generate an EZNEC file- a demo version of which can be downloaded from the EZNEC site. Dale W4OP |
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