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#1
July 3rd 10, 03:11 PM
posted to rec.radio.amateur.antenna
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coax short supply
"Ian Jackson" wrote in message ... But, when the coax is stretched, what happens to the characteristic impedance and the loss? [This is a (sort of) serious question!] -- Ian If the ratio of the conductors stay the same, there should not be a change except the losses go up. As you streach the coax, the shield and the center conductor will get smaller. Also the dialectric will have to get smaller. If they do not srink at the same ratio, the impedance will change depending on which conductor gets smaller the fastest. The losses will go up because the center conductor and the outer conductor are smaller. This is the simple IR loss of the conductors. It is the same as going from a rg-8 to a rg-58 type coax. |
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#2
July 3rd 10, 04:54 PM
posted to rec.radio.amateur.antenna
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coax short supply
On Jul 3, 10:11*am, "Ralph Mowery" wrote:
"Ian Jackson" wrote in message ... But, when the coax is stretched, what happens to the characteristic impedance and the loss? [This is a (sort of) serious question!] -- Ian If the ratio of the conductors stay the same, there should not be a change except the losses go up. *As you streach the coax, the shield and the center conductor will get smaller. *Also the dialectric will have to get smaller. If they do not srink at the same ratio, the impedance will change depending on which conductor gets smaller the fastest. The losses will go up because the center conductor and the outer conductor are smaller. *This is the simple IR loss of the conductors. *It is the same as going from a rg-8 to a rg-58 type coax. I'd be pleased to trade two buckets of prop wash for a coax stretcher. Any takers? Walt, W2DU |
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#3
July 3rd 10, 07:03 PM
posted to rec.radio.amateur.antenna
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coax short supply
In article
, walt wrote: I'd be pleased to trade two buckets of prop wash for a coax stretcher. Any takers? Walt- Contact Tucker Electronics to see if they are willing to deal! One such device is the General Radio 874LK20L line stretcher. Tucker may have them in stock. See http://www.tucker.com/java/jsp/produ...d17338_condR.h tm. The product is described in a GR document at http://www.tucker.com/images/images_spec/00001006.pdf. It is supposed to have a constant impedance. Fred K4DII |
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#4
July 3rd 10, 08:29 PM
posted to rec.radio.amateur.antenna
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coax short supply
On Jul 3, 2:03*pm, Fred McKenzie wrote:
In article , *walt wrote: I'd be pleased to trade two buckets of prop wash for a coax stretcher. Any takers? Walt- Contact Tucker Electronics to see if they are willing to deal! One such device is the General Radio 874LK20L line stretcher. *Tucker may have them in stock. See http://www.tucker.com/java/jsp/produ...d17338_condR.h tm. The product is described in a GR document at http://www.tucker.com/images/images_spec/00001006.pdf. *It is supposed to have a constant impedance. Fred K4DII Well Fred, I have a couple of GR line stretchers. What I need is a coax stretcher! Walt |
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#5
July 3rd 10, 10:15 PM
posted to rec.radio.amateur.antenna
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coax short supply
I seriously doubt if there is any shortage of copper for coax or any
other type feed line. It's probably more a matter of someone forgetting to order stock, or enough stock. Or, like gasoline, it's a contrived 'shortage'. As for a 'coax stretcher', all is not lost, I have one. No, I do not loan it out. I might be talked into selling it, but you probably couldn't afford it, sorry. - 'Doc |
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#6
July 3rd 10, 11:00 PM
posted to rec.radio.amateur.antenna
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coax short supply
On Jul 3, 11:54*am, walt wrote:
On Jul 3, 10:11*am, "Ralph Mowery" wrote: "Ian Jackson" wrote in message ... But, when the coax is stretched, what happens to the characteristic impedance and the loss? [This is a (sort of) serious question!] -- Ian If the ratio of the conductors stay the same, there should not be a change except the losses go up. *As you streach the coax, the shield and the center conductor will get smaller. *Also the dialectric will have to get smaller. If they do not srink at the same ratio, the impedance will change depending on which conductor gets smaller the fastest. The losses will go up because the center conductor and the outer conductor are smaller. *This is the simple IR loss of the conductors. *It is the same as going from a rg-8 to a rg-58 type coax. I'd be pleased to trade two buckets of prop wash for a coax stretcher. Any takers? Walt, W2DU I see your prop wash and will give you a left handed pipe wrench in exchange.If not the pipe wrench how about a can of muzzle blast? |
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#7
July 4th 10, 08:07 AM
posted to rec.radio.amateur.antenna
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coax short supply
In message
, BillyBobMarley writes On Jul 3, 11:54*am, walt wrote: On Jul 3, 10:11*am, "Ralph Mowery" wrote: "Ian Jackson" wrote in message ... But, when the coax is stretched, what happens to the characteristic impedance and the loss? [This is a (sort of) serious question!] -- Ian If the ratio of the conductors stay the same, there should not be a change except the losses go up. *As you streach the coax, the shield and the center conductor will get smaller. *Also the dialectric will have to get smaller. If they do not srink at the same ratio, the impedance will change depending on which conductor gets smaller the fastest. The losses will go up because the center conductor and the outer conductor are smaller. *This is the simple IR loss of the conductors. *It is the same as going from a rg-8 to a rg-58 type coax. I'd be pleased to trade two buckets of prop wash for a coax stretcher. Any takers? Walt, W2DU I see your prop wash and will give you a left handed pipe wrench in exchange.If not the pipe wrench how about a can of muzzle blast? I suppose a long screw is out of the question? -- Ian |
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#8
July 6th 10, 03:18 PM
posted to rec.radio.amateur.antenna
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coax short supply
Ian Jackson wrote:
In message , BillyBobMarley writes On Jul 3, 11:54 am, walt wrote: On Jul 3, 10:11 am, "Ralph Mowery" wrote: "Ian Jackson" wrote in message ... But, when the coax is stretched, what happens to the characteristic impedance and the loss? [This is a (sort of) serious question!] -- Ian If the ratio of the conductors stay the same, there should not be a change except the losses go up. As you streach the coax, the shield and the center conductor will get smaller. Also the dialectric will have to get smaller. If they do not srink at the same ratio, the impedance will change depending on which conductor gets smaller the fastest. The losses will go up because the center conductor and the outer conductor are smaller. This is the simple IR loss of the conductors. It is the same as going from a rg-8 to a rg-58 type coax. I'd be pleased to trade two buckets of prop wash for a coax stretcher. Any takers? Walt, W2DU I see your prop wash and will give you a left handed pipe wrench in exchange.If not the pipe wrench how about a can of muzzle blast? I suppose a long screw is out of the question? Must.....Resist..... Temptation.... |
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