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#1
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Allan Butler wrote:
Maybe use some capacitors from the control wires to ground to short out the rf right to ground before it gets to the toroids. The toroids then won't have so much rf to work with and they may not be as likely to saturate. Be careful with the capacitors that you get transmitting style that can handle a good amount of rf current. I've heard of doing this before, with the capacitors, so would this be the ceramic type? and how would i distinguish between "transmitting" style and regular capacitors? -- Registered Linux User #346565 http://www.tblx.net WA5K |
#2
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Jeremy Salch wrote:
I've heard of doing this before, with the capacitors, so would this be the ceramic type? and how would i distinguish between "transmitting" style and regular capacitors? Doorknobs are excellent but expensive. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#3
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Cecil Moore wrote:
Jeremy Salch wrote: I've heard of doing this before, with the capacitors, so would this be the ceramic type? and how would i distinguish between "transmitting" style and regular capacitors? Doorknobs are excellent but expensive. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- is that a kind of capacitor, or are you making fun of my not knowing the different kids of capacitors -- Registered Linux User #346565 http://www.tblx.net WA5K |
#4
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Jeremy Salch wrote:
Cecil Moore wrote: Jeremy Salch wrote: I've heard of doing this before, with the capacitors, so would this be the ceramic type? and how would i distinguish between "transmitting" style and regular capacitors? Doorknobs are excellent but expensive. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- is that a kind of capacitor, or are you making fun of my not knowing the different kids of capacitors No he is not making fun of you. There is a style of capacitor that is called a door knob for the shape that it is made in. To start out with go ahead and try some good high voltage ceramic capacitors from the control lines to ground. A fairly high value of 0.47 uF might do good in parallel with a .01 uF cap. For the toroids in the line they have to be fairly hefty as there could be some significant currents running on the lines at the different frequencies. If the toroids saturate they won't work as intended and can cause some real interesting things to happen. |
#5
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Jeremy Salch wrote:
is that a kind of capacitor, or are you making fun of my not knowing the different kids of capacitors I only make fun of gurus. :-) The doorknob is my favorite kind of capacitor. I have a couple of hundred of them. Here are some pictures of capacitors, including door knobs. http://www.surplussales.com/CapacitorsAll.html -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#6
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On Wed, 28 Apr 2004 13:06:59 -0500, Jeremy Salch
wrote: Allan Butler wrote: Maybe use some capacitors from the control wires to ground to short out the rf right to ground before it gets to the toroids. The toroids then won't have so much rf to work with and they may not be as likely to saturate. Be careful with the capacitors that you get transmitting style that can handle a good amount of rf current. I've heard of doing this before, with the capacitors, so would this be the ceramic type? and how would i distinguish between "transmitting" style and regular capacitors? Hi Jeremy, There should be no distinction between caps for this job - almost anything will work as the control voltages are so low that even dielectric breakdown is unlikely. On the other hand, the package style may be more carefully considered. The high end designs use what are called "feed-thru" button styles that are designed for bulkhead connections with a pig-tail on either side and the cap looks like a threaded stud with a collar. These are specifically designed to decouple rf off of dc lines. They provide the shortest lowest inductance path to ground (essentially zero lead length). These would be a must for UHF, but at HF you are just as well off with simple, leaded Micas, Ceramics, Paper-oil, polystyrene, tantalum, or any of a host of others. You don't really want massive capacitance (which is to say perhaps tantalums and like are unnecessary overkill) because 10,000pF is more than enough but 0.22mF works just as well. If you assist the cap with a small choke (on the noisy side of the current) you gain that much more isolation. Again, any value is better than none (but it hardly begs 1H audio chokes). 73's Richard Clark, KB7QHC |
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