On Tue, 08 Nov 2005 03:07:10 GMT, Owen Duffy wrote:

I often hear Rules of Thumb (ROT) like VSWR 3 is OK for coax and
25 if fine for open wire, or the converse... but something is lost in
the brief expression of those ROTs, and it seems more and more the
knowledge base of our hobby is the ROTs, rather than the underlying
principles. There is an appeal to the new experts in our hobby to
pickup the ROTs and parrot them... perhaps we need to take the time to
qualify what we say where learners are listening.

Owen

Owen,

The problem is that knowing the SWR is not worth much without knowing
the frequency and the spec's of the transmission line.

For example an SWR ratio of 10:1 using a hundred feet of RG-217 on
the 80-meter band is only about 1 dB loss. On 10-meters its a
different story.

I still subscribe to the belief that judging antenna performance based
solely upon SWR is like judging how well a automobile will perform
based solely on what the air pressure is in the tires.

Danny, K6MHE

email: k6mheatarrldotnet
http://www.k6mhe.com/

On Mon, 07 Nov 2005 19:16:08 -0800, Dan Richardson wrote:

On Tue, 08 Nov 2005 03:07:10 GMT, Owen Duffy wrote:

I often hear Rules of Thumb (ROT) like VSWR 3 is OK for coax and
25 if fine for open wire, or the converse... but something is lost in
the brief expression of those ROTs, and it seems more and more the
knowledge base of our hobby is the ROTs, rather than the underlying
principles. There is an appeal to the new experts in our hobby to
pickup the ROTs and parrot them... perhaps we need to take the time to
qualify what we say where learners are listening.

Owen

Owen,

The problem is that knowing the SWR is not worth much without knowing
the frequency and the spec's of the transmission line.

.... including the length. I agree fully.

Owen
--

On Tue, 08 Nov 2005 03:40:33 GMT, Owen Duffy wrote:

On Mon, 07 Nov 2005 19:16:08 -0800, Dan Richardson wrote:

On Tue, 08 Nov 2005 03:07:10 GMT, Owen Duffy wrote:

I often hear Rules of Thumb (ROT) like VSWR 3 is OK for coax and
25 if fine for open wire, or the converse... but something is lost in
the brief expression of those ROTs, and it seems more and more the
knowledge base of our hobby is the ROTs, rather than the underlying
principles. There is an appeal to the new experts in our hobby to
pickup the ROTs and parrot them... perhaps we need to take the time to
qualify what we say where learners are listening.

Owen

Owen,

The problem is that knowing the SWR is not worth much without knowing
the frequency and the spec's of the transmission line.

... including the length. I agree fully.

Owen

Yep, I forgot to add that.

Thanks

Danny, K6MHE

email: k6mheatarrldotnet
http://www.k6mhe.com/

Dan Richardson wrote -
The problem is that knowing the SWR is not worth much without
knowing
the frequency and the spec's of the transmission line.

==================================

The REAL problem is that very few people know the SWR on the
transmission line because the SWR meter doesn't measure it.

Aren't you are fooling yourselves?
----
Reg.

Reg Edwards wrote:
The REAL problem is that very few people know the SWR on the
transmission line because the SWR meter doesn't measure it.

Aren't you are fooling yourselves?

A host of us use EZNEC and other modeling programs, like
you publish, to estimate the SWR and therefore the losses.
--
73, Cecil http://www.qsl.net/w5dxp