Even with the increased price of copper these days, 3/4" thinwall copper
tubing is still pretty cheap. I recall that someone a few years ago
had, on a web page, a RF grounding installation made entirely of 3/4" or
1" copper tubing.
I'm a little surprised, though (not knowing any better) that the
inductance of a tube at HF is only as good as the tube flattened
(roughly equivalent to 1 1/4" strap - I would have thought it would be
closer to strap the size of the circumference of the tube, or twice that.
73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000
On 7/20/2010 11:59 PM, jimlux wrote:
> Cqtestk4xs@aol.com wrote:
>
>> In a message dated 7/21/2010 12:14:24 AM Greenwich Standard Time,
>> k0dan@comcast.net writes:
>>
>> Copper strap is REALLY expensive! Has anyone used welding cable with any
>> success and longevity? Other materials? My #4 grounds are OK, but how to
>> get
>> a lower impedance ground system without taking out a second mortgage?
>>
>> I was lucky enough to get some old air filled hardline which I pounded
>> flat and used that. It works if you only need short runs since it does take
>> some time to flatten.
>>
>
>
> A round tube has basically the same inductance as the same tube
> flattened (within a few percent)
>
> For a given amount of copper, a strip is better than a solid wire, but
> between hollow tube and strip, there's not much difference.
>
> The difference is that a strip can carry current on both sides, while a
> tube can only carry current on the outside. But that's true for a
> flattened tube too.
>
> If you were to split the tube and open it up, then you're looking more
> like a strip.
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