The amount of loss will depend on the cable you use
and the bands you are
interested in.  On the Cable Experts web page I see
the LMR 400 cable has a
loss of .7db per 100 feet at 30 Mhz, 1.5db loss at 150
Mhz and 2.7db loss at
450 Mhz.  If your interest is only hf then you should
be ok with the thicker
rg-213/9913 but for VHF/UHF you might want to consider
hardline, or you
might be able to live with a loss of 3db vhf and 6db
uhf? .  Also, you could
consider ladder line for HF, it has much less loss
than coax, you can
convert the ladder line to coax with a balun just
before you bring the line
into the shack.
Check out this web page:
http://www.amsat.org/amsat/articles/houston-net/coax.html

Using 2 meters for downlink, RG-8 would have a line
loss of 2 dB and on 70
cm a loss of 3.8 dB. RG-58 has a loss of 7 dB and 15
dB respectively. As you
can see between these two common types of coax you can
have significantly
greater gain by choosing RG-8 over RG-58.

But the 2 or 3.8dB loss is not acceptable in satellite
work. We would like
this loss to be as close to zero as possible since the
signals from the
satellites
are so weak.

Now, let's look at Belden 9913/9913F. On 2m, it has a
loss of 1.6 and on
70cm it is 2.8 dB. LMR-400 has a loss at 70cm of 2.7
dB and at 1 GHz 4.0 dB.
Half
inch hardline has a loss on 2m is only .9 dB and on
70cm it is 1.9 dB. This
-- when compared to RG-8 or RG-58 -- would be a
fantastic gain. Belden 9913
is a solid core coax. I use a coax that is similar to
Belden 9913 but is a
stranded core that makes it easier to manipulate and
will not crack as
easily
when it gets cold.

Belden 9913F is their new product that was not
available when I set up my
station. It is identical in properties to 9913 except
that it is a stranded
core
with foamed gas injected interior.

If you are going to work 1.2 gig, Belden 9913/9913F
loss would be 5.8 dB,
once again, the LMR-400 loss is only 4.0 dB and half
inch hardline loss is 3
dB.
...



...-.-
73, Ken -N5SWR

There are 10 types of people in the world, those who
understand binary and
those who don't.


-----Original Message-----
From: For blind ham radio operators
[mailto:[log in to unmask]]
On Behalf Of Gery Gaubert
Sent: Monday, November 26, 2007 9:33 AM
To: [log in to unmask]
Subject: length of coax

I finally got a tower.  40 ft.  I now have a problem
though.  I can only put
the tower in one place.  I will need to run abount 200
of coax to get from
the top of the tower to the radio.  I realize that the
shorter the run the
better the reception and probably the transmition. 
How much of a loss will
I experience?  I guess what I am trying to ask is can
I live with the loss?




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