[amsat-bb] Diplexer recommendation

[Rico van Genugten]

Hi all,

I'm using an FT-897D for TX (non-duplex), and an Airspy and computer for
RX. Good idea to use four switches Greg, in fact that's what I'm currently
doing. With four switches you always use one antenna for RX and the other
for TX though, I want to be able to use the same antenna for RX and TX when
that works better with the current satellite orientation. Using two
switches and two diplexers I would be able to independently select which
antenna to use for RX, and which one to use for TX. I posted the connection
scheme on twitter (warning, mspaint ahead):
https://twitter.com/PA3RVG/status/950649511935905792

But we are drifting from the original question: which diplexers? I have
heard good stories about the MFJ-916, but its availability is not great in
Europe. What about Comet, Diamond or Wimo? Are they any good?

Regards,
Rico


On Mon, Jan 8, 2018 at 11:04 PM, Greg D <ko6th.greg at gmail.com> wrote:

> But he has two cables going into the antenna (you can see them in the
> picture).
>
> I'm guessing by his hashtags that one of the radios is an RTLSDR dongle,
> so I can see the need for two cables and the switching from one "rig" to
> the other.  Presuming the other radio is not full-duplex.
>
> Perhaps the answer is to use 4 switches.  One pair for  the rigs, the
> other for the antennas.  Hook one side of the switched side directly
> through, the other cross-connected.  Just remember to set all 4 switches
> properly before transmitting!
>
> Greg  KO6TH
>
>
> Brad Brooks wrote:
> > I reckon the duplexer is required as there is no direct connections to
> > the 70cm antenna.
> >
> > Brad WF7T
> >
> > On Jan 8, 2018, 3:20 PM -0600, Greg D <ko6th.greg at gmail.com>, wrote:
> >> Hi Rico,
> >>
> >> So, two questions:
> >>
> >> First, what are you planning to use for your radio(s)? I'm a bit
> >> puzzled by the need to swap Tx and Rx connections, if you are using a
> >> diplexer. And, most of the satellite operations I do involve either two
> >> separate radios, or a satellite radio that has separate VHF and UHF
> >> antenna connections. In those cases, you'd not need the diplexer at
> >> all, since the purpose of a diplexer is to use one feed line to cover
> >> two antennas. Could you share your "two diplexers and two switches"
> >> diagram?
> >>
> >> Second, that's a really cool antenna that you have built. Are the plans
> >> available online somewhere?
> >>
> >> Greg KO6TH
> >>
> >>
> >> Rico van Genugten wrote:
> >>> Hi all,
> >>>
> >>> I'm slowly assembling my satellite base station setup bit by bit, I
> have
> >>> recently mounted an antenna system on my roof consisting of two
> >>> perpendicular VHF/UHF open-sleeve yagi's mounted at a fixed
> >>> elevation of 25
> >>> degrees on an azimuth rotator, more info here:
> >>> https://twitter.com/PA3RVG/status/942710621375815680
> >>>
> >>> So I have two feed lines coming into the house, both suitable for
> >>> VHF and
> >>> UHF operation. I want to be able to independently select one of the two
> >>> antennas for RX and TX. This can be realized using two diplexers and
> two
> >>> switches, but now for the million dollar question: Which diplexer?
> >>>
> >>> I'm curious to know which diplexers you guys use if you use them,
> >>> and which
> >>> can be recommended in terms of insertion loss, VSWR and isolation.
> >>> If you
> >>> believe the manufacturer specifications they are all great, but I'm
> more
> >>> interested in real life performance or test measurements.
> >>>
> >>> 73,
> >>> Rico
> >>> PA3RVG
> >>> _______________________________________________
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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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>
>