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#1
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It took a while to find the URL, but I think
many here will find the techniques shown to be very usefull. http://www.dxing.info/equipment/roll...own_bryant.pdf And while we are at it here is another usefull URL: making hi-Z to lo-Z transformers members.aol.com/DXerCapeCod/z_transformers.pdf Terry |
#2
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thank you kind Sir...
for the URL. Drifter... |
#4
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In article
, Telamon wrote: In article .com, wrote: It took a while to find the URL, but I think many here will find the techniques shown to be very usefull. http://www.dxing.info/equipment/roll...own_bryant.pdf And while we are at it here is another usefull URL: making hi-Z to lo-Z transformers members.aol.com/DXerCapeCod/z_transformers.pdf It doesn't have to be a transformer. It could be just three resistors in a T or delta configuration. You might be wondering why three resistors make up a splitter. The idea is that looking into any port of the splitter (signal connection) is supposed to look like 50 ohms with source and loads of 50 ohms on all ports. If you do a few calculations you will find a 16 to 17 ohm resistor (for all three) is about right for the T type. -- Telamon Ventura, California |
#5
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True but a resistive hyrbid/splitter has much more loss.
And the isolation between ports is not near as high as in a "good" transformer design. Terry |
#6
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In a pinch I have used simple "T" to split/parallel up to
three SW or scanners. While it did work, the LOs from one radio would show up in the other receivers. With VHF/UFH scanners this was a show stopper. With HF raceivers that up convert "T" work better then many of us would think. But I still prefer to use a tranformer based spliter/power divider. Terry |
#7
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#8
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Please review the informatin at:
http://www.microwaves101.com/encyclo..._splitters.cfm And note that a resistive splitter has: "Resistive power dividers are easy to understand, can be made very compact, and are naturally wideband, working down to zero frequency (DC). Their down side is that a two-way resistive splitter suffers 3 dB of real resistive loss, as opposed to a lossless splitter like a hybrid. Accounting for the 3 dB real loss and the 3 dB power split, the net power transfer loss you will observe from the input to one of the two outputs is 6.04 dB for a two-way resistive splitter. (Thanks, Dr. BKS, for helping us clarify that point!)" I own a Mini Circuits ZFSC-2-. It has a measured insertion loss of less then 3.5dB for 100KHz through 30MHz Another strength of tranformer based hybrids/power splitters is the greater isolation between power out ports. The Mini circuits ZFSC-2-1is rated for: 5 MHz 25dB isolation midband (~450MHz) 20dB isolation 500MHz 20 isolation These are minimum not typ[ical. My unit has been measued to have better then 25dB isolation between the power out ports from ~250KHz to above 30MHz. The isolation start to creep up below 250KHZ reaching a minimum of ~21dB at 100KHz. Below 100KHz the loss starts increasing and by 10KHZ the loss is just over 9dB and the isolation is down to just less then 15dB. The "roll your own splitter" page gives some real world loss and isolation data: http://www.dxing.info/equipment/roll...own_bryant.pdf MiniCircuits isloation PDF http://www.minicircuits.com/appnote/pwr2-4.pdf MiniCircuits hybrid/power splitter PDF http://www.minicircuits.com/appnote/psc2-2.pdf Quoting again frm the article on resistive splitters: "To put it simply, the resistive splitter has double the dBs compared to a lossless splitter's insertion loss. Thus a two-way resistive splitter transfers -6.04 dB power to each arm, a three-way splitter transfers -9.44 dB, a four-way transfers -12.08 db, etc." And: "The isolation of a resistive splitter is equal to its insertion loss." I hope that we can all agree that 3.5 dB loss is much better then 6dB loss and that 20dB isolation is better then 12dB isolation. I ued the wort case bad specs from minicircuits for loss and isolation. In the microwave world resitive splitters are the rule. In HF/VHF/UFH transformer splitters appear to dominate. Terry |
#9
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In article om,
wrote: Please review the informatin at: http://www.microwaves101.com/encyclo..._splitters.cfm And note that a resistive splitter has: "Resistive power dividers are easy to understand, can be made very compact, and are naturally wideband, working down to zero frequency (DC). Their down side is that a two-way resistive splitter suffers 3 dB of real resistive loss, as opposed to a lossless splitter like a hybrid. Accounting for the 3 dB real loss and the 3 dB power split, the net power transfer loss you will observe from the input to one of the two outputs is 6.04 dB for a two-way resistive splitter. (Thanks, Dr. BKS, for helping us clarify that point!)" I own a Mini Circuits ZFSC-2-. It has a measured insertion loss of less then 3.5dB for 100KHz through 30MHz Another strength of tranformer based hybrids/power splitters is the greater isolation between power out ports. The Mini circuits ZFSC-2-1is rated for: 5 MHz 25dB isolation midband (~450MHz) 20dB isolation 500MHz 20 isolation These are minimum not typ[ical. My unit has been measued to have better then 25dB isolation between the power out ports from ~250KHz to above 30MHz. The isolation start to creep up below 250KHZ reaching a minimum of ~21dB at 100KHz. Below 100KHz the loss starts increasing and by 10KHZ the loss is just over 9dB and the isolation is down to just less then 15dB. The "roll your own splitter" page gives some real world loss and isolation data: http://www.dxing.info/equipment/roll...own_bryant.pdf MiniCircuits isloation PDF http://www.minicircuits.com/appnote/pwr2-4.pdf MiniCircuits hybrid/power splitter PDF http://www.minicircuits.com/appnote/psc2-2.pdf Quoting again frm the article on resistive splitters: "To put it simply, the resistive splitter has double the dBs compared to a lossless splitter's insertion loss. Thus a two-way resistive splitter transfers -6.04 dB power to each arm, a three-way splitter transfers -9.44 dB, a four-way transfers -12.08 db, etc." And: "The isolation of a resistive splitter is equal to its insertion loss." I hope that we can all agree that 3.5 dB loss is much better then 6dB loss and that 20dB isolation is better then 12dB isolation. I ued the wort case bad specs from minicircuits for loss and isolation. In the microwave world resitive splitters are the rule. In HF/VHF/UFH transformer splitters appear to dominate. The higher you go in frequency the harder it is to make a transformer splitter. The loss figures are wrong. You will get better isolation between the ports with the transformer type which is why they are used at lower frequencies. -- Telamon Ventura, California |
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