"Jeff Liebermann" wrote in message
...
On Thu, 9 Jan 2014 21:08:11 -0800, "Sal" salmonella@food
poisoning.org wrote:

Another experiment I ran (back around 1975) was to take 100 feet of cable
and measure the loss, then repeat the measurement using a different 100
feet
made from ten different pieces. Yup, the loss was about 3 dB more,
indicative of an average 0.3 dB loss per joint, neatly within the range
you
specified.

0.3dB per connector at what frequency?

This is more fun:
http://802.11junk.com/jeffl/antennas/connector-loss/index.html
Just take every connector that you can find, put them in series, and
measure the loss. In this case, it was done at 2.4Ghz and 450MHz. End
to end loss at 2.4GHz was 2dB for about 25 adapters or about 0.08dB
per adapter. At 250MHz, the loss was about 0.2dB or 0.008dB per
adapter.

I've done similar demonstrations using two wattmeters at the local
radio club meeting. The results are typically that the adapter string
has the same loss as an equivalent length of small coax cable. I had
a surplus of BNC T connectors, so a strung about 50 of them in series
and obtained similar results.

Bottom line: Connectors and adapters aren't as evil as the data
sheets and literature suggest.

I agree.

To answer your question, my test generator output was Channel 3, so my
measurements were done about 61 MHz. I used all F-connectors, too, not
exactly a precision connector.

The reason I did the experiment [on USS Oriskany (CV-34), by the way] was
because my prior duties as an Electronic Warfare Tech exposed me to a
persistent rumor: Connectors cause a 3dB loss. I knew that it was nonsense
but I had never taken the time to conclusively disprove it before I moved to
the TV shop.

Related: I'm in a local group that's experimenting with mesh networking
(http://www.broadband-hamnet.org/). My first antenna connection required a
stack of four adapters, so last week I bought eight different adapters. I
should need only one. My big concern is not signal loss but the possibility
of snapping something plastic with a stupid long stack of connectors on the
back of a router.

"Sal"