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#21
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Stacking Winegard HD-6065P antennas
"Ian Jackson" The usual basic circuit is: Input port to ground - a 2:1 impedance ratio step-down ferrite-cored autotransformer T1 to ground. T1 tap is connected to the centre tap of a second 1:1 ratio ferrite-cored autotransformer T2. Each end of T2 of connected to each output port. A 100* ohm resistor R is connected between the ends of T2 (ie between the output ports). *R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the purpose of T2 and R is to provide isolation between the outputs (for signals coming back into the output ports). Now we are getting somewhere. The circuit you describe is differant from any that I have seen in my very short search for combiners. With nothing but transformers in the circuit I can see where the losses would only be part of a DB or so. Much differant than the combiners that I saw using either resistors or combinations of resistors and a single core 'transformer'. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
#22
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Stacking Winegard HD-6065P antennas
In message , Ralph
Mowery writes "Ian Jackson" The usual basic circuit is: Input port to ground - a 2:1 impedance ratio step-down ferrite-cored autotransformer T1 to ground. T1 tap is connected to the centre tap of a second 1:1 ratio ferrite-cored autotransformer T2. Each end of T2 of connected to each output port. A 100* ohm resistor R is connected between the ends of T2 (ie between the output ports). *R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the purpose of T2 and R is to provide isolation between the outputs (for signals coming back into the output ports). Now we are getting somewhere. The circuit you describe is differant from any that I have seen in my very short search for combiners. With nothing but transformers in the circuit I can see where the losses would only be part of a DB or so. Much differant than the combiners that I saw using either resistors or combinations of resistors and a single core 'transformer'. This circuit is used in 1001 makes of wideband FM/TV splitters (typically 5 to 900+MHz) and even in satellite IF splitters up to 2100MHz. It is also widely used for combining signals on different frequencies (where the loss is indeed 3-plus-some dB). However, while it CAN be used for combining co-phased antennas, it's more usual to use transmission lines (as have been described). Note that the small ferrite-cored transformers are completely suitable for putting any real RF power into, but transmission lines don't have this problem. -- Ian |
#23
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Stacking Winegard HD-6065P antennas
wrote:
"only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg |
#24
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Stacking Winegard HD-6065P antennas
On 1/6/2014 1:28 AM, gregz wrote:
wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. -- ================== Remove the "x" from my email address Jerry Stuckle JDS Computer Training Corp. ================== |
#25
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Stacking Winegard HD-6065P antennas
On Mon, 6 Jan 2014 06:28:11 +0000 (UTC), gregz
wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Nope. Power is by the square of the voltage: P = V^2 / R If you double the voltage, you get 4 times the power. A 1.414 times increase in voltage will produce twice the power. I tried to convert the antenna model of the HD-6066P antenna from the AO .ant format to .nec using 4NEC2 and failed. The plan was to model the stacked arrangement and see what happens: http://www.ham-radio.com/k6sti/hd6065p.htm The .ant file imported without error, the wire tables and images look correct, but the pattern is more like a point source than a gain antenna. I'll look at it later to see where I screwed up, but it would be nice if someone would look at the problem. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#26
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Stacking Winegard HD-6065P antennas
Jerry Stuckle wrote:
On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg |
#27
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Stacking Winegard HD-6065P antennas
On 1/6/2014 10:19 PM, gregz wrote:
Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg No, 2 microvolts would be four times the signal. Remember that power equals the voltage SQUARED divided by resistance. When you double the voltage, you also double the amperage (assuming resistance stays the same). -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
#28
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Stacking Winegard HD-6065P antennas
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz
wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#29
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Stacking Winegard HD-6065P antennas
On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
#30
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Stacking Winegard HD-6065P antennas
On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle
wrote: On 1/6/2014 11:04 PM, Jeff Liebermann wrote: On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz wrote: Jerry Stuckle wrote: On 1/6/2014 1:28 AM, gregz wrote: wrote: "only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one. John K9RZZ Twice the signal means twice the voltage, for me. Greg Twice the voltage is a 6 db gain. Twice the power is a 3db gain. Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal. Greg Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal voltage but only 1.414 times the signal power. That's why we have units of measure to avoid such ambiguities. Just to be difficult, working with antennas, the "signal" is the field strength measured in dBuV/M. If you define what you're measuring and specify your units of measure, you wouldn't be having such problems. You've got it backwards, Jeff. Twice the voltage is 4 times the power. 1.414 times the voltage would be twice the power. Very embarrassing. Temporary loss of IQ from working on my broken car with a cold or flu this afternoon. It should be: If you got 1 microvolt, 2 microvolts will be twice the signal voltage but 4 times the signal power. Thanks for the correction (grumble)... Maybe if I go to sleep early, when I wake up tomorrow, this didn't happen. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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