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#1
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Hello,
I'm looking for documentation explaning how to design and built directional couplers for 2m and 70 cm application. I've found a lot of links for the theory but nothing explaning how to compute the parameters and built it . Any suggestion appreciated Thanks Stephane, F1TJJ |
#2
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The ARRL handbooks have these off and on -- no parameter computation, just
things that work. The copy I have at my desk is 1976 (don't ask me why -- in 1976 they'd given up on tubes and were barely figuring out how to make decent solid-state circuits, but there you are). It has one for VHF/UHF, it's on page 636, and it's made mostly from copper pipe from a plumbing store. The UHF experamenter's manual probably has something, too. "Stéphane Rey" wrote in message ... Hello, I'm looking for documentation explaning how to design and built directional couplers for 2m and 70 cm application. I've found a lot of links for the theory but nothing explaning how to compute the parameters and built it . Any suggestion appreciated Thanks Stephane, F1TJJ |
#3
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Hey Tim, thanks for answer,
Could it be possible to have a copy of this page ? Stephane "Tim Wescott" wrote in message ... The ARRL handbooks have these off and on -- no parameter computation, just things that work. The copy I have at my desk is 1976 (don't ask me why -- in 1976 they'd given up on tubes and were barely figuring out how to make decent solid-state circuits, but there you are). It has one for VHF/UHF, it's on page 636, and it's made mostly from copper pipe from a plumbing store. The UHF experamenter's manual probably has something, too. "Stéphane Rey" wrote in message ... Hello, I'm looking for documentation explaning how to design and built directional couplers for 2m and 70 cm application. I've found a lot of links for the theory but nothing explaning how to compute the parameters and built it . Any suggestion appreciated Thanks Stephane, F1TJJ |
#4
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I'm not sure what's in current versions of the ARRL VHF/UHF manual,
but I know that older ones have articles on building SWR bridges. You can just delete the detectors if you want to use them as directional couplers. Also, you can download "RFSim99" for free, and you will find in it a little design ap for directional couplers, in microstrip, stripline, transformer-type, lumped and transmission line. The ap is under "tools--components--coupler" in the pulldown menus. Note that the microstrip and stripline assume the coupler is 1/4 wave long for the given coupling--something the ap fails to point out. Interestingly, 1/4 wave couplers (microstrip or stripline or the like) give the same coupling at 3/4 wave...in other words, at the third harmonic, which is useful for 146MHz and 440MHz. This is not true of the lumped. The transformer style depends on the bandwidth of the transformers. Cheers, Tom "Stéphane Rey" wrote in message ... Hello, I'm looking for documentation explaning how to design and built directional couplers for 2m and 70 cm application. I've found a lot of links for the theory but nothing explaning how to compute the parameters and built it . Any suggestion appreciated Thanks Stephane, F1TJJ |
#5
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Hey Tom,
Thanks a lot, I'm going to download this software and have a look. My mind was the power should be limited very low with PCB striplines, and I would like to design something up to about 100W. Stephane "Tom Bruhns" wrote in message m... I'm not sure what's in current versions of the ARRL VHF/UHF manual, but I know that older ones have articles on building SWR bridges. You can just delete the detectors if you want to use them as directional couplers. Also, you can download "RFSim99" for free, and you will find in it a little design ap for directional couplers, in microstrip, stripline, transformer-type, lumped and transmission line. The ap is under "tools--components--coupler" in the pulldown menus. Note that the microstrip and stripline assume the coupler is 1/4 wave long for the given coupling--something the ap fails to point out. Interestingly, 1/4 wave couplers (microstrip or stripline or the like) give the same coupling at 3/4 wave...in other words, at the third harmonic, which is useful for 146MHz and 440MHz. This is not true of the lumped. The transformer style depends on the bandwidth of the transformers. Cheers, Tom "Stéphane Rey" wrote in message ... Hello, I'm looking for documentation explaning how to design and built directional couplers for 2m and 70 cm application. I've found a lot of links for the theory but nothing explaning how to compute the parameters and built it . Any suggestion appreciated Thanks Stephane, F1TJJ |
#6
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Hi Stéphane,
Just so you don't confuse people you talk with, "stripline" is a line sandwiched between two ground planes (could be air dielectric or circuit board dielectric), but if it's a PC board with ground plane on one side and a trace on the other, that's "microstrip." I think 1.6mm thick fiberglass epoxy, with a 50 ohm microstrip line on it at about 3mm line width, will handle 100 W at 450MHz just fine. You can make a stripline or microstrip coupler that's shorter than 1/4 wave, and it should still have good directionality. It just won't have as much coupling as it does at 1/4 wave. The coupling at 1/4, 3/4, 5/4, etc., is all the same, and there are nulls at DC, 1/2 wave, 2/2, 3/3, etc. The maxima are rather broad, rounded, and not sharp peaks. I think I found a plot of the response on the web recently, but perhaps I made it from formulas. If you don't get it somewhere else, I can scan and send the ARRL article on making an SWR meter using copper pipe fittings. I suppose they are US-standard fittings, but there should be reasonable equivalents in the civilized metric world. Cheers, Tom "Stéphane Rey" wrote in message ... Hey Tom, Thanks a lot, I'm going to download this software and have a look. My mind was the power should be limited very low with PCB striplines, and I would like to design something up to about 100W. Stephane "Tom Bruhns" wrote in message m... I'm not sure what's in current versions of the ARRL VHF/UHF manual, but I know that older ones have articles on building SWR bridges. You can just delete the detectors if you want to use them as directional couplers. Also, you can download "RFSim99" for free, and you will find in it a little design ap for directional couplers, in microstrip, stripline, transformer-type, lumped and transmission line. The ap is under "tools--components--coupler" in the pulldown menus. Note that the microstrip and stripline assume the coupler is 1/4 wave long for the given coupling--something the ap fails to point out. Interestingly, 1/4 wave couplers (microstrip or stripline or the like) give the same coupling at 3/4 wave...in other words, at the third harmonic, which is useful for 146MHz and 440MHz. This is not true of the lumped. The transformer style depends on the bandwidth of the transformers. Cheers, Tom "Stéphane Rey" wrote in message ... Hello, I'm looking for documentation explaning how to design and built directional couplers for 2m and 70 cm application. I've found a lot of links for the theory but nothing explaning how to compute the parameters and built it . Any suggestion appreciated Thanks Stephane, F1TJJ |
#7
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I don't have a scanner, so if you help Stéphane here he'll get something
useful. "Tom Bruhns" wrote in message m... Hi Stéphane, Just so you don't confuse people you talk with, "stripline" is a line sandwiched between two ground planes (could be air dielectric or circuit board dielectric), but if it's a PC board with ground plane on one side and a trace on the other, that's "microstrip." I think 1.6mm thick fiberglass epoxy, with a 50 ohm microstrip line on it at about 3mm line width, will handle 100 W at 450MHz just fine. You can make a stripline or microstrip coupler that's shorter than 1/4 wave, and it should still have good directionality. It just won't have as much coupling as it does at 1/4 wave. The coupling at 1/4, 3/4, 5/4, etc., is all the same, and there are nulls at DC, 1/2 wave, 2/2, 3/3, etc. The maxima are rather broad, rounded, and not sharp peaks. I think I found a plot of the response on the web recently, but perhaps I made it from formulas. If you don't get it somewhere else, I can scan and send the ARRL article on making an SWR meter using copper pipe fittings. I suppose they are US-standard fittings, but there should be reasonable equivalents in the civilized metric world. Cheers, Tom |
#8
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OK...Stéphane, would a scan of a couple articles still be helpful?
I found the ARRL one last night, and also a similar but somewhat better one in the old RSGB/Jessop VHF/UHF manual. Guess I can scan both. And thank to Wim for the reference. It's one I'd seen before but had lost the link to, and appreciate having it again. Cheers, Tom "Tim Wescott" wrote in message ... I don't have a scanner, so if you help Stéphane here he'll get something useful. "Tom Bruhns" wrote in message m... .... If you don't get it somewhere else, I can scan and send the ARRL article on making an SWR meter using copper pipe fittings. I suppose they are US-standard fittings, but there should be reasonable equivalents in the civilized metric world. |
#9
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I'm looking for documentation explaning how to design and built
directional couplers for 2m and 70 cm application. This site has a design program http://www.ee.bilkent.edu.tr/~microw...upler/dcoupler. htm Wim |
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