Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
Question about the Timewave ANC-4
I have a question about how the ANC-4 works. Specifically, it's about
the antennas that you connect to the ANC-4 in order to cancel noise or make a 'phased array'. In some contexts, when noise is a problem, people will say that you want to keep the "noise antenna" that you use with the ANC-4 as small as possible. This is because you want the noise antenna to hear *only* the noise, which will be phased out, and not the target signal, which you don't want to be phased out. The suggestion here is clearly that, if your noise antenna *does* hear the target signal, you're going lose signal along with noise. However, when people use the ANC-4 to establish phased arrays of two or more antennas, this is usually with a couple of serious antennas, widely separated, *both* of which can hear the target signal. Hence my question: When the ANC-4 is connected to two largish antennas, both of which are capable of hearing the target signal, what prevents the desired signal from simply being phased out? Is determining what gets phased out just a matter of carefully adjusting the controls on the ANC-4? Thanks! Steve |
#2
|
|||
|
|||
Question about the Timewave ANC-4
Steve wrote:
I have a question about how the ANC-4 works. Specifically, it's about the antennas that you connect to the ANC-4 in order to cancel noise or make a 'phased array'. In some contexts, when noise is a problem, people will say that you want to keep the "noise antenna" that you use with the ANC-4 as small as possible. This is because you want the noise antenna to hear *only* the noise, which will be phased out, and not the target signal, which you don't want to be phased out. The suggestion here is clearly that, if your noise antenna *does* hear the target signal, you're going lose signal along with noise. However, when people use the ANC-4 to establish phased arrays of two or more antennas, this is usually with a couple of serious antennas, widely separated, *both* of which can hear the target signal. Hence my question: When the ANC-4 is connected to two largish antennas, both of which are capable of hearing the target signal, what prevents the desired signal from simply being phased out? Is determining what gets phased out just a matter of carefully adjusting the controls on the ANC-4? Thanks! Steve Hi Steve, You might get a better response from the folks over at rec.radio.amateur.antenna |
#3
|
|||
|
|||
Question about the Timewave ANC-4
I have eight antennas combined in 7 ANC-4's.
If you use the two serious antenna approach, you simply steer a null onto the noise source. Unless the desired signal is in the same direction, it's not cancelled. Depending on the separation and orientation of the array, it may even be enhanced (in a peak of the pattern of the phased pair) while the noise is eliminated (in a null of the pattern of the phased pair). Generally a quarter wave of separation is good, giving you a peak at one endfire while you have a null at the other endfire. In general the null will be a V pattern that you sweep from one endfire, opening up at broadside to a line, and closing at the other endfire, as you tune the phasing and gain. And more generally than noise sources, you can cancel out a local broadcaster and listen to what's under it, by steering your null onto him, though it can be a tricky adjustment, since you need an insanely deep null, so you're dealing in fractions of a degree. -- Ron Hardin On the internet, nobody knows you're a jerk. |
#4
|
|||
|
|||
Question about the Timewave ANC-4
On Thu, 31 Aug 2006 01:32:40 GMT, Ron Hardin
wrote: I have eight antennas combined in 7 ANC-4's. If you use the two serious antenna approach, you simply steer a null onto the noise source. Unless the desired signal is in the same direction, it's not cancelled. Depending on the separation and orientation of the array, it may even be enhanced (in a peak of the pattern of the phased pair) while the noise is eliminated (in a null of the pattern of the phased pair). Generally a quarter wave of separation is good, giving you a peak at one endfire while you have a null at the other endfire. In general the null will be a V pattern that you sweep from one endfire, opening up at broadside to a line, and closing at the other endfire, as you tune the phasing and gain. And more generally than noise sources, you can cancel out a local broadcaster and listen to what's under it, by steering your null onto him, though it can be a tricky adjustment, since you need an insanely deep null, so you're dealing in fractions of a degree. You should point out your antennas are active verticals of the Dymek DA-100E type. It's not possible to steer an array of random wires with any precision. http://www.universal-radio.com/CATALOG/sw_ant/0328.html |
#5
|
|||
|
|||
Question about the Timewave ANC-4
David wrote:
You should point out your antennas are active verticals of the Dymek DA-100E type. It's not possible to steer an array of random wires with any precision. http://www.universal-radio.com/CATALOG/sw_ant/0328.html It doesn't matter. Precision doesn't come into it any more or less with random wires. -- Ron Hardin On the internet, nobody knows you're a jerk. |
#6
|
|||
|
|||
Question about the Timewave ANC-4
On Thu, 31 Aug 2006 08:27:40 GMT, Ron Hardin
wrote: It doesn't matter. Precision doesn't come into it any more or less with random wires. A random wire is already full of nulls and nodes. Much easier to phase vertical omnis. |
#7
|
|||
|
|||
Question about the Timewave ANC-4
In article ,
"A. Pismo Clam" wrote: Steve wrote: I have a question about how the ANC-4 works. Specifically, it's about the antennas that you connect to the ANC-4 in order to cancel noise or make a 'phased array'. In some contexts, when noise is a problem, people will say that you want to keep the "noise antenna" that you use with the ANC-4 as small as possible. This is because you want the noise antenna to hear *only* the noise, which will be phased out, and not the target signal, which you don't want to be phased out. The suggestion here is clearly that, if your noise antenna *does* hear the target signal, you're going lose signal along with noise. However, when people use the ANC-4 to establish phased arrays of two or more antennas, this is usually with a couple of serious antennas, widely separated, *both* of which can hear the target signal. Hence my question: When the ANC-4 is connected to two largish antennas, both of which are capable of hearing the target signal, what prevents the desired signal from simply being phased out? Is determining what gets phased out just a matter of carefully adjusting the controls on the ANC-4? Thanks! Steve Hi Steve, You might get a better response from the folks over at rec.radio.amateur.antenna I would not recommend rec.radio.amateur.antenna to anybody for any reason. -- Telamon Ventura, California |
#8
|
|||
|
|||
Question about the Timewave ANC-4
In article .com,
Steve wrote: In some contexts, when noise is a problem, people will say that you want to keep the "noise antenna" that you use with the ANC-4 as small as possible. This is because you want the noise antenna to hear *only* the noise, which will be phased out, and not the target signal, which you don't want to be phased out. The suggestion here is clearly that, if your noise antenna *does* hear the target signal, you're going lose signal along with noise. However, when people use the ANC-4 to establish phased arrays of two or more antennas, this is usually with a couple of serious antennas, widely separated, *both* of which can hear the target signal. Hence my question: When the ANC-4 is connected to two largish antennas, both of which are capable of hearing the target signal, what prevents the desired signal from simply being phased out? Is determining what gets phased out just a matter of carefully adjusting the controls on the ANC-4? A noise bridge works by subtracting the noise from the signal. (The adjustments work by making the time delay, the polarity, and the amplitude of the noise antenna signal to be the same as the noise coming in on the main antenna so it can be subtracted). Thus forming an antenna that, electrically, looks like the difference between the two antennas. So, to work, you need two antennas that receive the noise and desired signals in different ratios. Say, you have a main antenna that picks up signal and noise, and you have a noise antenna that picks up 10 times as much noise as the signal. After you adjust your noise bridge to match the amplitude, the desired signal on the noise channel is only one tenth that on the main antenna, and that's all you'll lose. You can get this different noise-to-desired ratio by either putting the noise antenna as close as possible to the source, or using a directional antenna. As I remember another poster there, (Ron Hardin?), it often works better to use a loop to null out the desired signal and just get the noise and then use the ANC-4 to combine that with another antenna. Mark Zenier Googleproofaddress(account:mzenier provider:eskimo domain:com) |
#9
|
|||
|
|||
Question about the Timewave ANC-4
Steve wrote: I have a question about how the ANC-4 works. Specifically, it's about the antennas that you connect to the ANC-4 in order to cancel noise or make a 'phased array'. In some contexts, when noise is a problem, people will say that you want to keep the "noise antenna" that you use with the ANC-4 as small as possible. This is because you want the noise antenna to hear *only* the noise, which will be phased out, and not the target signal, which you don't want to be phased out. The suggestion here is clearly that, if your noise antenna *does* hear the target signal, you're going lose signal along with noise. However, when people use the ANC-4 to establish phased arrays of two or more antennas, this is usually with a couple of serious antennas, widely separated, *both* of which can hear the target signal. Hence my question: When the ANC-4 is connected to two largish antennas, both of which are capable of hearing the target signal, what prevents the desired signal from simply being phased out? Is determining what gets phased out just a matter of carefully adjusting the controls on the ANC-4? Thanks! Steve By this time I've used the ANC-4 enough to know that it's a big help. Where noise is concerned, it makes much more of a difference for me than running off batteries, ferrite cores, etc. I'm kicking myself for not getting one of these sooner. I find that my noise floor usually drops one or two S-units the instant I turn the ANC-4 on. Adjusting the controls then can make a huge difference; and at my location it almost always makes more of a difference than is necessary to compensate for the 6 dB insertion loss. It especially shines during the day on LSB and USB. I've tried it with a lot of different antennas, but I'll be experimenting with antennas for quite some time, I suspect. I did eventually get good results using the H-800 active whip. However, where noise reduction is concerned, I find that I get the best results using a wire antenna that snakes its way between my house and the neighbor's house and then back near some power lines. The nulls with the wire antenna are just as deep as they are with the H-800, but they're a lot easier to find. These conclusions are pretty tentative, though, as I am still experimenting and trying out different arrangements. On the whole, I think the ANC-4 is great and worth every penny if you have problems with noise. It works as advertised. Steve |
#10
|
|||
|
|||
Question about the Timewave ANC-4
Steve = tks 4 that, a very informative and interesting post.
I want to ask the group this: I had a MFJ-1026 noise canceller when I lived in suburban Joburg. I tried every sort of antenna combination - verticals, horizontals, whips and Windom's, but the thing never abated the noise to any appreciable extent, so I gave up on it after a year of fiddling and experimenting. Now I have passed it on to a friend who lives in a very noisy suburb of Cape Town. He did no better than me with it and also gave up on it. Now he has a Wellbrook ALA1530 which gives him decent results. So my question is this: Is the Timewave ANC-4 markedly superior to the MFJ1026? -- John Plimmer, Montagu, Western Cape Province, South Africa South 33 d 47 m 32 s, East 20 d 07 m 32 s RX Icom IC-756 PRO III with MW mods Drake SW8 & ERGO software Sony 7600D, GE SRIII, Redsun RP2100 BW XCR 30, Braun T1000, Sangean 818 & 803A. GE circa 50's radiogram Antenna's RF Systems DX 1 Pro, Datong AD-270 Kiwa MW Loop http://www.dxing.info/about/dxers/plimmer.dx "Steve" wrote in message oups.com... By this time I've used the ANC-4 enough to know that it's a big help. Where noise is concerned, it makes much more of a difference for me than running off batteries, ferrite cores, etc. I'm kicking myself for not getting one of these sooner. I find that my noise floor usually drops one or two S-units the instant I turn the ANC-4 on. Adjusting the controls then can make a huge difference; and at my location it almost always makes more of a difference than is necessary to compensate for the 6 dB insertion loss. It especially shines during the day on LSB and USB. I've tried it with a lot of different antennas, but I'll be experimenting with antennas for quite some time, I suspect. I did eventually get good results using the H-800 active whip. However, where noise reduction is concerned, I find that I get the best results using a wire antenna that snakes its way between my house and the neighbor's house and then back near some power lines. The nulls with the wire antenna are just as deep as they are with the H-800, but they're a lot easier to find. These conclusions are pretty tentative, though, as I am still experimenting and trying out different arrangements. On the whole, I think the ANC-4 is great and worth every penny if you have problems with noise. It works as advertised. Steve |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
For Sale TimeWave DSP-59+ DSP unit | Scanner | |||
Stupid question G5RV | Antenna | |||
transmitter question - its a dousy | Homebrew | |||
transmitter question - its a dousy | Homebrew | |||
transmitter question - its a dousy | Equipment |