[amsat-bb] Re: Diplexer

[Anthony Monteiro]

Hi Bob,

It is simple really - all of the common gadgets sold
for ham use as duplexers are really diplexers that
can be used as duplexers or diplexers :)

And Dom is correct. The microwave Radars used
a similar principle but with 1/4 wave sections of
waveguide instead of coax. The gas tubes would short
the waveguides when the transmitter was on making
the other end a high impedance and disconnecting the
receiver.

73,
Tony AA2TX
---

At 04:56 PM 4/9/2011, Bob- W7LRD wrote:

>  I'm really trying to "absorb" all this diplexers/duplexor 
> thread.  Specifically I have a new FT-8800 and want to run  FM sats 
> from my truck.  Not wanting to reinvent the wheel would a simple 
> dual band whip suffice.  Then maybe requiring a preamp, and how all 
> that works maybe with a di/du etc.  My head is starting to hurt.
>
>73 Bob W7LRD
>----- Original Message -----
>From: "Andrew Rich" <vk4tec at tech-software.net>
>To: kc6uqh at cox.net, "i8cvs" <domenico.i8cvs at tin.it>, "Amsat - BBs" 
><amsat-bb at amsat.org>, "Anthony Monteiro" <aa2tx at comcast.net>
>Sent: Saturday, April 9, 2011 1:39:01 PM
>Subject: [amsat-bb] Re: Diplexer
>
>DU = TX RX
>DI = RX
>----- Original Message -----
>From: "Art McBride" <kc6uqh at cox.net>
>To: "'i8cvs'" <domenico.i8cvs at tin.it>; "'Amsat - BBs'" <amsat-bb at amsat.org>;
>"'Anthony Monteiro'" <aa2tx at comcast.net>
>Sent: Sunday, April 10, 2011 6:27 AM
>Subject: [amsat-bb] Re: Diplexer
>
>
> > As I understand it,
> > A Duplexer allows for transmission and reception to take place in the same
> > band using a single band antenna.
> > A Diplexer allows for transmission and reception to take place on
> > different
> > bands using a multi-band antenna.
> >
> > Art,
> > KC6UQH
> >
> > -----Original Message-----
> > From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
> > Behalf Of i8cvs
> > Sent: Saturday, April 09, 2011 10:35 AM
> > To: Amsat - BBs; Anthony Monteiro
> > Subject: [amsat-bb] Re: Diplexer
> >
> > ----- Original Message -----
> > From: "Anthony Monteiro" <aa2tx at comcast.net>
> > To: <amsat-bb at amsat.org>
> > Sent: Saturday, April 09, 2011 5:15 PM
> > Subject: [amsat-bb] Re: Diplexer
> >
> >> A "duplexor" is a device that allows both transmitting and
> >> receiving over the same transmission line or antenna. It
> >> may or may not be a passive device and it may or may not
> >> be frequency selective.
> >>
> >> In WWII RADAR systems, a duplexor was used to allow
> >> the transmitter and receiver on the same frequency to
> >> share the same antenna. The duplexor was a waveguide
> >> device that had special gas-filled tubes to quickly
> >> switch the signal direction.
> >>
> >> 73,
> >> Tony AA2TX
> >>
> > Hi Tony, AA2TX
> >
> > I have in my hands the Instruction Book for Radar Recognition
> > Sets AN/UPX-6  of U.S. Navy  Department Bureau of Ships.
> >
> > The UPX6 is a IFF transponder on board of aicrafts and was used
> > in WWII for  Identification of Friend or Foe.
> >
> > The UPX-6  can transmit from 1010-1030 MHz and receive from
> > 1090-1110 MHz and allows both transmitting and receiving over
> > the same transmission line and antenna via a circuit  made of coax
> > cable RG-58/CU that the manual calls a   "DUPLEXER" and not
> > a "duplexor".
> >
> > This "duplexer" is working on the fact that a transmission line,
> > shorted at the far end a quarter wavelenght long for the incoming
> > signal,represent infinite impedance (an open circuit) at the sending
> > end of the line.
> >
> > The UPX-6 was converted in the early 1980's to be used on 1296 MHz
> > and an interesting article written by W6NBI was published in Ham
> > Radio Magazine march 1981
> >
> > I modified it and I got 40 watt output.......not too bad for that epoch
> > time !
> >
> > Best 73" de
> >
> > i8CVS Domenico
> > _______________________________________________
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