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#1
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In article
, " wrote: On Jun 25, 5:29*pm, "Justtis" wrote: Anyone know of a good site offering build plans. *Prefer plans from someone who has built and used same. I need a quiet antenna like this and Wellbrook is just too expensive!http://www.wellbrook.uk.com/index.html I use the ALA100 with home brew loops. Damn good, but you are right that it is expensive. The ALA100 is the cheapest of the Wellbrook products. They have some variants of it now. You need a good radio to use an untuned loop since it delivers a huge amount of RF. SNIP So stop whining about the cost and build a low cost passive loop. It if works well but you still need further improvement it will at least tide you over. All the amplification does for you is allow the loop to be smaller, which may mostly be a convenience depending on the environment. Be sure to build a balanced loop that only responds to the magnetic field. -- Telamon Ventura, California |
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#2
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I'm not whining about the cost of a homemade
loop! Where did you get that from? Please re read the messages! You seem to have run them together!! "Telamon" wrote in message ... In article , " wrote: On Jun 25, 5:29 pm, "Justtis" wrote: Anyone know of a good site offering build plans. Prefer plans from someone who has built and used same. I need a quiet antenna like this and Wellbrook is just too expensive!http://www.wellbrook.uk.com/index.html I use the ALA100 with home brew loops. Damn good, but you are right that it is expensive. The ALA100 is the cheapest of the Wellbrook products. They have some variants of it now. You need a good radio to use an untuned loop since it delivers a huge amount of RF. SNIP So stop whining about the cost and build a low cost passive loop. It if works well but you still need further improvement it will at least tide you over. All the amplification does for you is allow the loop to be smaller, which may mostly be a convenience depending on the environment. Be sure to build a balanced loop that only responds to the magnetic field. -- Telamon Ventura, California |
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#3
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On Jun 28, 6:17*pm, Telamon
wrote: In article , " wrote: On Jun 25, 5:29*pm, "Justtis" wrote: Anyone know of a good site offering build plans. *Prefer plans from someone who has built and used same. I need a quiet antenna like this and Wellbrook is just too expensive!http://www.wellbrook.uk.com/index.html I use the ALA100 with home brew loops. Damn good, but you are right that it is expensive. The ALA100 is the cheapest of the Wellbrook products. They have some variants of it now. You need a good radio to use an untuned loop since it delivers a huge amount of RF. SNIP So stop whining about the cost and build a low cost passive loop. It if works well but you still need further improvement it will at least tide you over. All the amplification does for you is allow the loop to be smaller, which may mostly be a convenience depending on the environment. Be sure to build a balanced loop that only responds to the magnetic field. -- Telamon Ventura, California I saw your other post on the subject. Feeding a loop to a 50 ohm input of a radio will not work well since once side of the loop will be at ground. This is where the wideband transformer comes into play. You can float the loop above ground if you have the transformer. It is possible to do the same with a differential amp, but good transformer would be lower noise. |
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#4
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In article
, " wrote: On Jun 28, 6:17*pm, Telamon wrote: In article , " wrote: On Jun 25, 5:29*pm, "Justtis" wrote: Anyone know of a good site offering build plans. *Prefer plans from someone who has built and used same. I need a quiet antenna like this and Wellbrook is just too expensive!http://www.wellbrook.uk.com/index.html I use the ALA100 with home brew loops. Damn good, but you are right that it is expensive. The ALA100 is the cheapest of the Wellbrook products. They have some variants of it now. You need a good radio to use an untuned loop since it delivers a huge amount of RF. SNIP So stop whining about the cost and build a low cost passive loop. It if works well but you still need further improvement it will at least tide you over. All the amplification does for you is allow the loop to be smaller, which may mostly be a convenience depending on the environment. Be sure to build a balanced loop that only responds to the magnetic field. I saw your other post on the subject. Feeding a loop to a 50 ohm input of a radio will not work well since once side of the loop will be at ground. It works very well. I have several loop antennas. This is where the wideband transformer comes into play. You can float the loop above ground if you have the transformer. It is possible to do the same with a differential amp, but good transformer would be lower noise. The transformer is not necessary for a connection to the coax or a balanced amplifier input. You could clamp a few ferrite cores around the coax lead-in to the radio at the antenna connection to block noise coming from the radio if you don't already have the radio plugged into a EMI noise suppression power strip. -- Telamon Ventura, California |
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#5
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On Jun 29, 7:25*pm, Telamon
wrote: In article , " wrote: On Jun 28, 6:17*pm, Telamon wrote: In article , " wrote: On Jun 25, 5:29*pm, "Justtis" wrote: Anyone know of a good site offering build plans. *Prefer plans from someone who has built and used same. I need a quiet antenna like this and Wellbrook is just too expensive!http://www.wellbrook.uk.com/index.html I use the ALA100 with home brew loops. Damn good, but you are right that it is expensive. The ALA100 is the cheapest of the Wellbrook products. They have some variants of it now. You need a good radio to use an untuned loop since it delivers a huge amount of RF. SNIP So stop whining about the cost and build a low cost passive loop. It if works well but you still need further improvement it will at least tide you over. All the amplification does for you is allow the loop to be smaller, which may mostly be a convenience depending on the environment. Be sure to build a balanced loop that only responds to the magnetic field. I saw your other post on the subject. Feeding a loop to a 50 ohm input of a radio will not work well since once side of the loop will be at ground. It works very well. I have several loop antennas. This is where the wideband transformer comes into play. You can float the loop above ground if you have the transformer. It is possible to do the same with a differential amp, but *good transformer would be lower noise. The transformer is not necessary for a connection to the coax or a balanced amplifier input. You could clamp a few ferrite cores around the coax lead-in to the radio at the antenna connection to block noise coming from the radio if you don't already have the radio plugged into a EMI noise suppression power strip. -- Telamon Ventura, California Er, is there a reason you don't want to do this correctly? The thing with shortwave is you can toss out a piece of wire and get something. It is all a matter of digging the signal out of the noise. In any event, the transformers are easily purchased on ebay. Or in surplus shops if I don't beat you to them. |
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#6
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On Jun 28, 4:10*pm, " wrote:
On Jun 25, 5:29*pm, "Justtis" wrote: Anyone know of a good site offering build plans. *Prefer plans from someone who has built and used same. I need a quiet antenna like this and Wellbrook is just too expensive!http://www.wellbrook.uk.com/index.html I use the ALA100 with home brew loops. Damn good, but you are right that it is expensive. The ALA100 is the cheapest of the Wellbrook products. They have some variants of it now. You need a good radio to use an untuned loop since it delivers a huge amount of RF. I suspect the ALA100 is just a wideband transformer and a common gate amp. You can get North Hills wideband transformers on ebay. I have a few of these transformers, but haven't got around to trying to make a home brew wellbrook. I found half a dozen North Hills 1301LB transformers in a surplus shop and wiped out their stock at $6 a pop. Oh, and I'm being a jerk and hoarding them. If you don't want to pay for a North Hills transformer, I suspect any passive video over twisted pair transformer will do the trick. I was thinking of using one unbal to bal to feed the source of a depletion mode JFET, ground the gate, then use the balanced end of another transformer as the load, tying the free end to the power supply, bypassed to ground, and of course the other end in series with the drain. Then feed the unbalanced side to the radio. If you had enough of these transformers, you could probably make a multicoupler using the same dcheme. Instead of one transformer in the path of the source, use several. There is some misconception that the Wellbrook loops are shielded. - the pipe that you see is the loop itself. Greater Surface {Effect} Area and Relative Greater Signal Capture Area over a single strand of Wire. ~ RHF |
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