[amsat-bb] Cables loss

[Bob]

Hi Roger,

Well RG213 isn't your optimal choice of cable.  For example it has a loss
that is about twice as high as similar sized LMR400, and that really has an
impact on 70 cm.  At 80 feet you are losing well over half your TX power --
your 30 watts into the coax will turn into about 12 watts at the antenna.
At that distance LMR600 is probably worth it.

I've used a pair of M2 Eggbeaters since 1998, so they have been up 20 years
now.  I do use a SSB Electronics mast-mounted preamp on each.  My lengths
are 50 feet for 70 cm, and 75 feet for 2 meters.  I run 50 watts.
Generally I have no problem making a few contacts each pass.  Things work
well for about 1/3 of the pass, and fair for another 1/3 of the pass, and
not at all for 1/3 of the pass.  In other words, you aren't going to be
working stations down at the horizon, but you will be working stations when
the satellite is closest to you and higher in the sky.

In my case I probably didn't need the mast mounted preamp as my cable loss
was fairly low.  In your case you are losing around 4 dB in your coax (for
a mode VU bird).  You can probably do without the preamp.

73, Bob, WB4SON

On Thu, Jul 19, 2018 at 6:41 AM, Roger Titmuss <OLDBIKER at sky.com> wrote:

> Hi as a newcomer to this part of the hobby I have a couple of questions.
>
>
>
> 1. When using the M2 egg beaters how important is it to install a masthead
> preamplifier?
>
>
>
> 2. Again with egg beater will 30 watts be enough to get back to the bird?
>
>
>
> I am using about 80 feet of RG213 to connect the antenna.
>
>
>
>
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> Many thanks
>
>
>
> Roger G0AWY
>
>
>
> 73
>
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