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Long wire to SO-239 50 ohm?
On Fri, 26 Jan 2007 02:03:04 GMT, Telamon
wrote: In article , David wrote: On Thu, 25 Jan 2007 03:06:28 GMT, Telamon wrote: If you use a cable TV Balun you'll get a quick and dirty 4:1 transformer and a marked improvement. http://www.radioshack.com/product/in...2&cp=&sr=1&ori gkw=matching+transformer&kw=matching+transformer&p arentPage=search Those don't work well below 10 MHz. 15 MHz and higher they are OK. How do you know? I tested them. What is the low frequency limiting component? I didn't go as far as that. This unit is made of a ferrite core and a couple of very small value capacitors. I would guess the core was the problem. I've reverse engineered a bunch of them. The ones with caps are very rare. |
#2
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Long wire to SO-239 50 ohm?
On Jan 26, 6:11 am, David wrote: On Fri, 26 Jan 2007 02:03:04 GMT, Telamon wrote: In article , David wrote: On Thu, 25 Jan 2007 03:06:28 GMT, Telamon wrote: If you use a cable TV Balun you'll get a quick and dirty 4:1 transformer and a marked improvement. http://www.radioshack.com/product/in...103912&cp=&sr=... gkw=matching+transformer&kw=matching+transformer&p arentPage=search Those don't work well below 10 MHz. 15 MHz and higher they are OK. How do you know? I tested them. What is the low frequency limiting component? - - I didn't go as far as that. - - This unit is made of a ferrite core and - - a couple of very small value capacitors. - - I would guess the core was the problem. - - I've reverse engineered a bunch of them. - The ones with caps are very rare. Offhand - I can only come up with two reasons to put Capacitors in-side a Matching Transformer : 1 - To make it [Narrow] Band Specific {Tuned} 2 - To make it [Wide] Band Rejection {High -or- Low} I would suspect that any TV type Matching Transformer that had Capacitors in-side it would be designed to have them act as part of a Low Band Rejection Filter for the AM/MW {Shortwave} Band and 'pass' only the Higher VHF and UHF TV Bands. somebody educate me please ~ RHF |
#3
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About Baluns - What is the Best Balun ?
On Jan 26, 9:21 am, "RHF" wrote: On Jan 26, 6:11 am, David wrote: On Fri, 26 Jan 2007 02:03:04 GMT, Telamon wrote: In article , David wrote: On Thu, 25 Jan 2007 03:06:28 GMT, Telamon wrote: If you use a cable TV Balun you'll get a quick and dirty 4:1 transformer and a marked improvement. http://www.radioshack.com/product/in...103912&cp=&sr=... gkw=matching+transformer&kw=matching+transformer&p arentPage=search Those don't work well below 10 MHz. 15 MHz and higher they are OK. How do you know? I tested them. What is the low frequency limiting component?- - I didn't go as far as that. - - This unit is made of a ferrite core and - - a couple of very small value capacitors. - - I would guess the core was the problem. - - I've reverse engineered a bunch of them. - The ones with caps are very rare. - Offhand - I can only come up with two reasons to - put Capacitors in-side a Matching Transformer : - 1 - To make it [Narrow] Band Specific {Tuned} - 2 - To make it [Wide] Band Rejection {High -or- Low} Example - Shortwave Baluns and Accessories http://www.kintronic.com/site/subassemblies/baluns.asp Kintronic Laboratories offers two types of Shortwave Baluns. First is a discrete Discrete Component Shortwave Balun with Tunable Capacitors to permit a 1:1 Match at any Frequency in a Single Shortwave (HF) Band of operation. New Longwire Balun 9:1 Transformer High Performer -by- LowBander on eBay http://cgi.ebay.com/_W0QQitemZ180078653482 About Baluns - What is the Best Balun ? http://dxantennas.com/wst_page4.php bail-um-out ~ RHF |
#4
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About Baluns - What is the Best Balun ?
In article . com,
"RHF" wrote: On Jan 26, 9:21 am, "RHF" wrote: On Jan 26, 6:11 am, David wrote: On Fri, 26 Jan 2007 02:03:04 GMT, Telamon wrote: In article , David wrote: On Thu, 25 Jan 2007 03:06:28 GMT, Telamon wrote: If you use a cable TV Balun you'll get a quick and dirty 4:1 transformer and a marked improvement. http://www.radioshack.com/product/in...=2103912&cp=&s r=... gkw=matching+transformer&kw=matching+transformer&p arentPage=search Those don't work well below 10 MHz. 15 MHz and higher they are OK. How do you know? I tested them. What is the low frequency limiting component?- - I didn't go as far as that. - - This unit is made of a ferrite core and - - a couple of very small value capacitors. - - I would guess the core was the problem. - - I've reverse engineered a bunch of them. - The ones with caps are very rare. - Offhand - I can only come up with two reasons to - put Capacitors in-side a Matching Transformer : - 1 - To make it [Narrow] Band Specific {Tuned} - 2 - To make it [Wide] Band Rejection {High -or- Low} Example - Shortwave Baluns and Accessories http://www.kintronic.com/site/subassemblies/baluns.asp Kintronic Laboratories offers two types of Shortwave Baluns. First is a discrete Discrete Component Shortwave Balun with Tunable Capacitors to permit a 1:1 Match at any Frequency in a Single Shortwave (HF) Band of operation. New Longwire Balun 9:1 Transformer High Performer -by- LowBander on eBay http://cgi.ebay.com/_W0QQitemZ180078653482 About Baluns - What is the Best Balun ? http://dxantennas.com/wst_page4.php Snip That would depend on the application like anything engineered. In general the current type would be best for Hertzian antennas and I would only use the voltage type on random/long wire Marconi type antennas. -- Telamon Ventura, California |
#5
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About Baluns - What is the Best Balun ?
On Sat, 27 Jan 2007 12:05:57 -0800, Telamon
wrote: Snip That would depend on the application like anything engineered. In general the current type would be best for Hertzian antennas and I would only use the voltage type on random/long wire Marconi type antennas. http://www.moonraker.com.au/techni/q...everticals.htm |
#6
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About Baluns - What is the Best Balun ?
In article ,
David wrote: On Sat, 27 Jan 2007 12:05:57 -0800, Telamon wrote: Snip That would depend on the application like anything engineered. In general the current type would be best for Hertzian antennas and I would only use the voltage type on random/long wire Marconi type antennas. http://www.moonraker.com.au/techni/q...everticals.htm What does this have to do with BALUNs? -- Telamon Ventura, California |
#7
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About Baluns - What is the Best Balun ?
On Sat, 27 Jan 2007 17:55:17 -0800, Telamon
wrote: In article , David wrote: On Sat, 27 Jan 2007 12:05:57 -0800, Telamon wrote: Snip That would depend on the application like anything engineered. In general the current type would be best for Hertzian antennas and I would only use the voltage type on random/long wire Marconi type antennas. http://www.moonraker.com.au/techni/q...everticals.htm What does this have to do with BALUNs? A random wire is not a Marconi antenna. A Marconi antenna is a 1/4 wave vertical with a formal ground screen/radial system providing a second 1/4 wave image below the earth which allows the system to load like (but radiate like) a half-wave antenna. A Marconi antenna is ca. 36 Ohms and needs no 9:1 or 10:1 transformer. |
#8
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About Baluns - What is the Best Balun ?
RHF wrote: On Jan 26, 9:21 am, "RHF" wrote: On Jan 26, 6:11 am, David wrote: On Fri, 26 Jan 2007 02:03:04 GMT, Telamon wrote: In article , David wrote: On Thu, 25 Jan 2007 03:06:28 GMT, Telamon wrote: If you use a cable TV Balun you'll get a quick and dirty 4:1 transformer and a marked improvement. http://www.radioshack.com/product/in...103912&cp=&sr=... gkw=matching+transformer&kw=matching+transformer&p arentPage=search Those don't work well below 10 MHz. 15 MHz and higher they are OK. How do you know? I tested them. What is the low frequency limiting component?- - I didn't go as far as that. - - This unit is made of a ferrite core and - - a couple of very small value capacitors. - - I would guess the core was the problem. - - I've reverse engineered a bunch of them. - The ones with caps are very rare. - Offhand - I can only come up with two reasons to - put Capacitors in-side a Matching Transformer : - 1 - To make it [Narrow] Band Specific {Tuned} - 2 - To make it [Wide] Band Rejection {High -or- Low} Example - Shortwave Baluns and Accessories http://www.kintronic.com/site/subassemblies/baluns.asp Kintronic Laboratories offers two types of Shortwave Baluns. First is a discrete Discrete Component Shortwave Balun with Tunable Capacitors to permit a 1:1 Match at any Frequency in a Single Shortwave (HF) Band of operation. New Longwire Balun 9:1 Transformer High Performer -by- LowBander on eBay http://cgi.ebay.com/_W0QQitemZ180078653482 About Baluns - What is the Best Balun ? The best ones are the ones I build myself! I have one that has been in use since 1988. dxAce Michigan USA |
#9
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Long wire to SO-239 50 ohm?
In article ,
David wrote: On Fri, 26 Jan 2007 02:03:04 GMT, Telamon wrote: In article , David wrote: On Thu, 25 Jan 2007 03:06:28 GMT, Telamon wrote: If you use a cable TV Balun you'll get a quick and dirty 4:1 transformer and a marked improvement. http://www.radioshack.com/product/in...3912&cp=&sr=1& ori gkw=matching+transformer&kw=matching+transformer&p arentPage=search Those don't work well below 10 MHz. 15 MHz and higher they are OK. How do you know? I tested them. What is the low frequency limiting component? I didn't go as far as that. This unit is made of a ferrite core and a couple of very small value capacitors. I would guess the core was the problem. I've reverse engineered a bunch of them. The ones with caps are very rare. The one you referenced has the capacitors. I would go with another model. -- Telamon Ventura, California |
#10
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Long wire to SO-239 50 ohm?
On Fri, 26 Jan 2007 17:16:54 -0800, Telamon
wrote: The one you referenced has the capacitors. I would go with another model. I was just showing the picture. If the thing has caps, replace them with shiny jumpers. |
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