[amsat-bb] Station advice: coax

Tue Nov 20 03:05:55 UTC 2018

Triplexer/Duplexers work quite nicely for most satellite operations. At
least for the LEOs and AO-7.

Comments like "plague" paint with too broad a brush and are  not
technically sound.

73, N0AN
Hasan

On Mon, Nov 19, 2018 at 8:58 PM <niederwil1388 at gmail.com> wrote:

> Mark, you suggested that you would ". . . avoid the diplexer like the
> plague."     Why exactly?
>
> I use a Comet CFX 4310C at each end of 60' of cable.
>
>  .3dB not 3 dB of insertion loss.
>
> CFX-4310C
> 2M/440/1200MHz Triplexer
>
> Band Pass        Loss      Max Power
> 1.3-150MHz        .25dB      1000W PEP
>  350-500MHz     .25dB        500W PEP
>  840-1400MHz  0.3dB        200W PEP
>
> Isolation: 50dB
>
> One run of cable and one surge protector with three antennas. In operation
> for 25 years with no problems.
>
> 73,
>
> Ron VA7VW
>
>
> -----Original Message-----
> From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Mark D. Johns
> Sent: Saturday, November 17, 2018 12:06 PM
> To: wd9get at amsat.org
> Cc: AMSAT <amsat-bb at amsat.org>
> Subject: Re: [amsat-bb] Station advice: coax
>
> With that kind of coax run, you'll definitely want the lowest loss
> feedline you can afford, and you'll probably want the pre-amps sooner than
> later. If hard line is out of the picture, LMR 600 is a good alternative.
> Several outlets will sell custom lengths with connectors attached. You can
> get by with LMR 400 or Belden 9913 on the 2 meter side, but loss at 435 MHz
> will be greater. I would avoid the diplexer like the plague.
>
> As GEO mentioned, you really only need the flexy stuff at the point where
> things are rotating. I run LMR 600 to the pre-amp, just below the rotor,
> and ultra-flex from the pre-amp to the antenna. A good, moderate-cost
> alternative for pre-amps are the "Mini" pre-amps from SHF Elektronik in
> Germany http://www.shf-elektronik.de/en/
> --
> Mark D. Johns
> KØJM / MØGZO / ex-9H3DJ / ex-KØMDJ
> Brooklyn Park, MN USA   EN35hd
> -----------------------------------------------
> "Heaven goes by favor; if it went by merit,
>    you would stay out and your dog would go in."
>     ---Mark Twain
>
>
> On Sat, Nov 17, 2018 at 1:12 PM GEO Badger via AMSAT-BB <
> amsat-bb at amsat.org>
> wrote:
>
> > Keith,
> > You want the lowest loss coax you can afford for your run. ½" hard
> > line would be a good choice, though not inexpensive and neither are
> > the connectors. Plus it is rather rigid and can be difficult to handle.
> > Terminate it at the rotator and use a flexible jumper from there to
> > the antennas.
> > To use a diplexer you'll need one at both ends, assuming 2 antennas.
> > Recall that a diplexer will have insertion loss of >3 dB. And that I
> > don't believe they will pass DC. Though I haven't ever checked that.
> > ---  Ciao baby, catch you on the flip side.
> >  GEO
> >
> >  http://www.w3ab.org
> >
> > Time flies like an arrow, fruit flies like a banana.
> >
> >       From: "Keith E. Brandt, WD9GET" <wd9get at amsat.org>
> >  To: amsat-bb at amsat.org
> >  Sent: Saturday, November 17, 2018 10:11 AM
> >  Subject: [amsat-bb] Station advice: coax
> >
> > There's been a lot of good station advice on the reflector recently
> > that I've really appreciated. I'm slowly but surely building up my sat
> > ground station. I've got my Yaesu G5400B connected and running and
> > I've got an antenna plan. The next issue is running coax.
> >
> > What's the recommendation on coax runs? It looks like I'll have
> > between
> > 75 and 100 ft from the shack to the mount. I can envision running a
> > separate line for 2m and 440, but is it also effective to use a
> > diplexer at the antenna? Does that limit my ability to later add a
> > mast-mounted preamp with power-over-coax? (I'll probably add preamp(s)
> > at a later date)
> >
> > Is the ultraflex coax really necessary for hooking up around the
> > rotator? I'm sure it's better, but is it really worth the extra cost?
> > I certainly don't want to pay the high price for ultraflex for the
> > full run, especially if I'm using two lines.
> >
> > Thoughts appreciated.
> >
> > 73,
> > Keith
> > --
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Keith E. Brandt, MD, MPH
> > /wd9get at amsat.org/
> >
> > /Christianity and science are opposed… but only in the same sense as
> > my thumb and forefinger are opposed- and between them I can grasp
> > everything.
> > /—Sir William Bragg (Nobel Prize for Physics- 1915)
> >
> > *This message transmitted with 100% recycled electrons
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> _______________________________________________
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> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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