Less than 1/2 the loss of RG-214 but yet the same diameter:

http://www.timesmicrowave.com/content/pdf/lmr/22-25.pdf

Made for outdoor use. Better shielding (solid in addition to braid) more
flexible, better UV protection, 20 year life expectancy. Much better
performance over its lifetime. When it finally does degrade to near the
dismal performance of RG-214, then replace it. It's even cheaper than most
places charge for RG-214 at retail.

Thanks for the link...

If you've been following the other threads on the subject, LMR-400DB is my
choice - until some expert convinces me that milspec 214 is a better bet.

The PDF shows the waterproof nature of the DB; I'm not sure my
correspondents in the other forum where several EEs/Hams are debating the
subject have seen the linked stuff. I'll put it up there.

That said, there's gotta be a reason the military uses milspec stuff, at
well over double the cost, perhaps included being the double braided jacket
making RF migration/insertion pretty much impossible...

Ideas about that?

L8R

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"Stanley Tobasco" wrote in message
...
Less than 1/2 the loss of RG-214 but yet the same diameter:

http://www.timesmicrowave.com/content/pdf/lmr/22-25.pdf

Made for outdoor use. Better shielding (solid in addition to braid) more
flexible, better UV protection, 20 year life expectancy. Much better
performance over its lifetime. When it finally does degrade to near the
dismal performance of RG-214, then replace it. It's even cheaper than most
places charge for RG-214 at retail.

"Flying Pig" wrote in message
...
..

That said, there's gotta be a reason the military uses milspec stuff, at
well over double the cost, perhaps included being the double braided
jacket making RF migration/insertion pretty much impossible...

Ideas about that?


Double braid still gives only 95% shielding. The LMR400 is 100% shielded
because of the solid foil in the outer jacket.

As far as the "milspec" hype:

http://en.wikipedia.org/wiki/Coaxial_cable

"A series of standard types of coaxial cable were specified for military
uses, in the form "RG-#" or "RG-#/U". They date from WW II and were listed
in MIL-HDBK-216 published in 1962. These designations are now obsolete. The
RG designation stands for Radio Guide, the U designation stands for
Universal. The current military standard is MIL-SPEC MIL-C-17. MIL-C-17
numbers, such as "M17/75-RG214," are given for military cables and
manufacturer's catalog numbers for civilian applications. However, the
RG-series designations were so common for generations that they are still
used, although critical users should be aware that since the handbook is
withdrawn there is no standard to guarantee the electrical and physical
characteristics of a cable described as "RG-# type". The RG designators are
mostly used to identify compatible connectors that fit the inner conductor,
dielectric, and jacket dimensions of the old RG-series cables."

If someone starts quoting "milspec" you can bet they haven't a clue what
"milspec" even means. A fair amount of "milspec" electronics can't endure
automotive temperature ranges, oil field conditions or other industrial
settings. Buy what suits your application best. The center conductor in the
PTFE filled RG-214 is prone to migration because teflon is easily displaced.
There are minimal bend radius for the cable.

If you have any leakage in your cable (such as RG214 does with only 95%
shield) and you place it in a conductive solution (such as salt water) you
are in effect adding a third coaxial conductor to the transmission line.
This will change the impedance of the line, increase signal loss and radiate
radio energy.

On Sun, 13 Dec 2009 16:16:34 -0700, "Stanley Tobasco"
wrote:




Double braid still gives only 95% shielding. The LMR400 is 100% shielded
because of the solid foil in the outer jacket.

Aluminum foil as I recall - good stuff indoors.

On Sun, 13 Dec 2009 16:43:19 -0500, "Flying Pig"
wrote:

That said, there's gotta be a reason the military uses milspec stuff, at
well over double the cost, perhaps included being the double braided jacket
making RF migration/insertion pretty much impossible...

Ideas about that?

Yes.

Don't forget the silver plated conductors and teflon insulation.

On 13/12/2009 21:12, Stanley Tobasco wrote:
Less than 1/2 the loss of RG-214 but yet the same diameter:

http://www.timesmicrowave.com/content/pdf/lmr/22-25.pdf

Made for outdoor use. Better shielding (solid in addition to braid) more
flexible, better UV protection, 20 year life expectancy. Much better
performance over its lifetime. When it finally does degrade to near the
dismal performance of RG-214, then replace it. It's even cheaper than most
places charge for RG-214 at retail.



A (slightly) lossy cable could save your radio if the antenna drops off
the top of the mast, otherwise it could see a short circuit if the far
end goes open circuit..

On Sun, 13 Dec 2009 14:12:30 -0700, "Stanley Tobasco"
wrote:

Less than 1/2 the loss of RG-214 but yet the same diameter:

http://www.timesmicrowave.com/content/pdf/lmr/22-25.pdf

Made for outdoor use. Better shielding (solid in addition to braid) more
flexible, better UV protection, 20 year life expectancy. Much better
performance over its lifetime. When it finally does degrade to near the
dismal performance of RG-214, then replace it. It's even cheaper than most
places charge for RG-214 at retail.


The US Navy has the expertise and budget to evaluate any cable that is
available.

Why are they using RG-214 ??

Perhaps because aluminum foil and foam cores do not hold up in a salt
air environment ??