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#1
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"tommyknocker" wrote in message ... I was looking for a shorter RG58 cable in RS a couple weeks ago because my 20' was all wound up (not enough room) and it was causing QRM. ???!!! |
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#2
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CW wrote:
"tommyknocker" wrote in message ... I was looking for a shorter RG58 cable in RS a couple weeks ago because my 20' was all wound up (not enough room) and it was causing QRM. ???!!! Heh. The 20' lead in coax cable for my SW antenna-the cable I'd usedin a pinch when I moved in-was too long for the space it needed to cover, and it was picking up spurious signals (electronic noise and such). I know this because the signal would improve when I moved the coax. So I went to RS to buy a shorter lead in cable. |
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#3
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If your coax is picking up signal then you have system problems. Just using
coax without proper configuration is a waste of money. You might as well use hook up wire. In a properly functioning setup, that extra length would actually be beneficial if it had any effect at all. A length of coax in a coil can act as a very effective RF choke. "tommyknocker" wrote in message ... CW wrote: "tommyknocker" wrote in message ... I was looking for a shorter RG58 cable in RS a couple weeks ago because my 20' was all wound up (not enough room) and it was causing QRM. ???!!! Heh. The 20' lead in coax cable for my SW antenna-the cable I'd usedin a pinch when I moved in-was too long for the space it needed to cover, and it was picking up spurious signals (electronic noise and such). I know this because the signal would improve when I moved the coax. So I went to RS to buy a shorter lead in cable. |
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#4
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tommyknocker wrote:
Heh. The 20' lead in coax cable for my SW antenna-the cable I'd usedin a pinch when I moved in-was too long for the space it needed to cover, and it was picking up spurious signals (electronic noise and such). Moving coax around should have no effect at all. How is your system grounded? -- John Miller Email address: domain, n4vu.com; username, jsm Neutrinos are into physicists. |
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#5
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John Miller wrote:
tommyknocker wrote: Heh. The 20' lead in coax cable for my SW antenna-the cable I'd usedin a pinch when I moved in-was too long for the space it needed to cover, and it was picking up spurious signals (electronic noise and such). Moving coax around should have no effect at all. How is your system grounded? Insulated, stranded copper wire hooked to a small pole stuck in the earth. |
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#6
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tommyknocker wrote:
John Miller wrote: Moving coax around should have no effect at all. How is your system grounded? Insulated, stranded copper wire hooked to a small pole stuck in the earth. You have a multimeter? While your rig is all connected up, measure the voltage, both DC and AC, between the shield of the coax and the ground "hole" of one of your wall sockets. Please note that I am *not* suggesting that your house electrical ground is a good RF ground (although it could possibly be better than a small pole in the ground). But if there's significant difference in electrical potential, it's a good indication that your radio grounding system needs work or re-thinking. Maybe someone can post a link to a site with good grounding info. -- John Miller Email address: domain, n4vu.com; username, jsm In Tulsa, Oklahoma, it is against the law to open a soda bottle without the supervision of a licensed engineer. |
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#7
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But if there's
significant difference in electrical potential, it's a good indication that your radio grounding system needs work or re-thinking. Maybe someone can post a link to a site with good grounding info. I know you're right there John, I'm not txing yet so everything in my shack is just receiving so I didn't think it'd make that big a deal. But I spent about a whole day in just concentrating on each piece and properly grounding everything and it was the best 'accesorie' ;-) I ever bought. The difference in the noise floor, which was low to begin with because of my location, dropped noticably......to the point that I think I actually posted a thread in here trying to convince people, that if their receivers weren't *properly* grounded to get out there and ground them. You won't be sorry, heck with the lightening thing (even though it's a biggie), just in your dxing experience. |
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