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#1
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I've been reading about these and am intrigued.
These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? Thanks, Steve |
#2
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In article . com,
"Steve" wrote: I've been reading about these and am intrigued. These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? Sloping the antenna is an attempt to cause it to be more broadband. This is not much help on reception but allows the antenna to be used over a wider range of frequencies on transmit due to a reduction in VSWR. The termination resistor causes the antenna to be lossy and helps with the VSWR aspect on transmit but is no help on reception. The matching section is also a wast of time on receive. You are better off using a broadband transformer. There is nothing great about this antenna for reception. You are better off using a folded dipole. -- Telamon Ventura, California |
#3
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On Thu, 09 Nov 2006 04:11:26 GMT, Telamon
wrote: In article . com, "Steve" wrote: I've been reading about these and am intrigued. These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? Sloping the antenna is an attempt to cause it to be more broadband. This is not much help on reception but allows the antenna to be used over a wider range of frequencies on transmit due to a reduction in VSWR. The termination resistor causes the antenna to be lossy and helps with the VSWR aspect on transmit but is no help on reception. The matching section is also a wast of time on receive. You are better off using a broadband transformer. There is nothing great about this antenna for reception. You are better off using a folded dipole. ??? I would disregard everything written above. The antenna is very quiet for receive. |
#4
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![]() David wrote: On Thu, 09 Nov 2006 04:11:26 GMT, Telamon wrote: In article . com, "Steve" wrote: I've been reading about these and am intrigued. These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? Sloping the antenna is an attempt to cause it to be more broadband. This is not much help on reception but allows the antenna to be used over a wider range of frequencies on transmit due to a reduction in VSWR. The termination resistor causes the antenna to be lossy and helps with the VSWR aspect on transmit but is no help on reception. The matching section is also a wast of time on receive. You are better off using a broadband transformer. There is nothing great about this antenna for reception. You are better off using a folded dipole. ??? I would disregard everything written above. The antenna is very quiet for receive. I found it to be 'quiet' because it really didn't receive very well. I built two and chucked 'em both soon after. dxAce Michigan USA |
#5
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![]() "dxAce" wrote in message ... David wrote: On Thu, 09 Nov 2006 04:11:26 GMT, Telamon wrote: In article . com, "Steve" wrote: I've been reading about these and am intrigued. These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? Sloping the antenna is an attempt to cause it to be more broadband. This is not much help on reception but allows the antenna to be used over a wider range of frequencies on transmit due to a reduction in VSWR. The termination resistor causes the antenna to be lossy and helps with the VSWR aspect on transmit but is no help on reception. The matching section is also a wast of time on receive. You are better off using a broadband transformer. There is nothing great about this antenna for reception. You are better off using a folded dipole. ??? I would disregard everything written above. The antenna is very quiet for receive. I found it to be 'quiet' because it really didn't receive very well. I built two and chucked 'em both soon after. dxAce Michigan USA Leave it to Rickets. BH |
#6
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dxAce wrote:
David wrote: On Thu, 09 Nov 2006 04:11:26 GMT, Telamon wrote: In article . com, "Steve" wrote: I've been reading about these and am intrigued. These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? There is nothing great about this antenna for reception. You are better off using a folded dipole. ??? I would disregard everything written above. The antenna is very quiet for receive. I found it to be 'quiet' because it really didn't receive very well. I built two and chucked 'em both soon after. I'm amazed at how many people I read put down the T2FD after the great experiences I've had with it. Maybe those who knock it already have a better low-noise antenna system in place. I've never lived in a house where I could erect a 200 foot Doty longwire a good distance from any noise source. My RF Systems T2FD is probably the next best thing. My first house was in a Philly suburb, close-in neighbors and lots of RFI around but none getting into my receiver. Pulled in a lot of low powered, weak but clean signals from all around the world. I'm still amazed at some of the stations I've heard with it. My second house was much better RFI-wise but reception was every bit as good in my first, proving to me that it was indeed the antenna keeping the man-made noise out. They are reputed to have low gain compared to other antennas, but the total absence of interfering noise more than makes up for it. Try listening to a radio in a noisy room, you need volume (gain) to compensate for the enviornment. In a quiet room, you can turn the volume (gain) down because its not neccessary, and also much more relaxing and easier to listen to. Invest in good coax, as there's no point in a low noise antenna without a good shield coax. My RF Systems antenna is 47 feet long, not too easy to hide but not a monster if you have a good location to run it. One ham operator in my town had a B&W T2FD over 90 feet long and I don't know how many times I walked by his house before I noticed it. The length determines the optimum frequency range. This one I have is designed for 3.5-35 MHz. I am planning on modifying it to 35 feet long and take off 6 inches in height to make it fit my current yard, as right now I'm really in a tight spot! That'd put the optimum low frequency at 4.75 MHz. They receive below the low frequency of course but performance seems to drop off a bit. |
#7
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In article ,
dxAce wrote: David wrote: On Thu, 09 Nov 2006 04:11:26 GMT, Telamon wrote: In article . com, "Steve" wrote: I've been reading about these and am intrigued. These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? Sloping the antenna is an attempt to cause it to be more broadband. This is not much help on reception but allows the antenna to be used over a wider range of frequencies on transmit due to a reduction in VSWR. The termination resistor causes the antenna to be lossy and helps with the VSWR aspect on transmit but is no help on reception. The matching section is also a wast of time on receive. You are better off using a broadband transformer. There is nothing great about this antenna for reception. You are better off using a folded dipole. ??? I would disregard everything written above. The antenna is very quiet for receive. I found it to be 'quiet' because it really didn't receive very well. I built two and chucked 'em both soon after. I disregard everything Dave writes. If he could pay attention, which unfortunately he can't he would recognize that the T2FD is basically a folded dipole with modifications so it will load up on transmit. Those modifications are a waste of time on receive and the reasons given are the rational unlike the advice given by the short attention span guy. As DxAce found out it will not pick up the signal levels his current fairly long horizontal wires will with or without the T2FD modifications. -- Telamon Ventura, California |
#8
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On Fri, 10 Nov 2006 02:56:42 GMT, Telamon
wrote: I disregard everything Dave writes. If he could pay attention, which unfortunately he can't he would recognize that the T2FD is basically a folded dipole No ''basically'' about it. It is a (relatively) wideband folded dipole. http://www.hard-core-dx.com/nordicdx...wire/t2fd.html |
#9
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"Steve" wrote:
I've been reading about these and am intrigued. These antennas are often mounted in a sloping configuration, but how steep can the angle be? I'm sure the steepness of the angle is going to effect the antenna's radiation pattern, but will how? Does it cause the antenna to become highly directional as the angle increases? Actually, the idea behind the slope is to make it more omnidirectional. The ideal slope is something like 30 degrees, but there's no hard-and-fast rule on this. Set it up as best you can. How do these antennas perform in relatively noisy environments? I've read that they're relatively slow to pick up local noise, but I'd like to hear about some people's first hand experiences with them. I absolutely love mine. Or loved -- it came down and was heavily damaged in a windstorm, so I've been stuck using an end-fed wire instead. It seems to be far less sensitive to near-field noise than the longwire, and yet had nearly the same signal strength from most directions. The longwire is 400 feet long and has an extensive grounding and radial network, so it's not exactly a slouch in the receive department... but the T2FD was a better overall performer. I just have to rebuild it now. Are these antennas inevitably eyesores to those philistines who don't appreciate the beauty of a good antenna? Is there a way to make them less conspicuous? Mine was quite visible, and I thought of it as an eyesore, but my neighbors didn't even notice it. It is heavy, visible, and provides a lot of wind loading with all the spacers it needs. I live in a *very* high wind area and mine would always come down. I ended up with a counterweight system to allow it to get blown out of shape by quite a bit and then return to normal when the wind died down... but that may not be necessary where you live. I don't know of a good way to make them less conspicuous unless you want to play around with using very high strength material with a dark color for the spacers -- something that doesn't have to be too thick. Mine used PVC spacers and was ugly, but I live in the boonies and could get away with it. Thanks, Steve Hope this is helpful, Eric -- Eric F. Richards "Nature abhors a vacuum tube." -- Myron Glass, often attributed to J. R. Pierce, Bell Labs, c. 1940 |
#10
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Telamon wrote:
I disregard everything Dave writes. If he could pay attention, which unfortunately he can't he would recognize that the T2FD is basically a folded dipole with modifications so it will load up on transmit. Those modifications are a waste of time on receive and the reasons given are the rational unlike the advice given by the short attention span guy. As DxAce found out it will not pick up the signal levels his current fairly long horizontal wires will with or without the T2FD modifications. Sorry, Telemon, but I disagree with you here. A stopped clock is right twice a day, and so it is with Dave here. Yes, the resistor is to avoid standing waves and turn it into a more travelling wave antenna, much like such terrible receive antennas like the Beverage and the Rhombic. (*sarcasm*) My personal experience with wires and a T2FD is that the T2FD was overall the better antenna with the wires having only occasional advantages and some frequencies AND directions. The wires, BTW, have extensive ground networks and about 20 ground radials. For those not familiar with this antenna, this page is a good jumping-off point for information (be sure to follow some of the related links): http://www.hard-core-dx.com/nordicdx...wire/t2fd.html The late Joe Carr was an unabashed fan of this antenna, and he certainly was a respected antenna authority for receive antennas with a number of books under his belt, at least one of which was a technically oriented book. Regards, -- Eric F. Richards "Nature abhors a vacuum tube." -- Myron Glass, often attributed to J. R. Pierce, Bell Labs, c. 1940 |
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