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@tech-software.net To: kc6uqh@cox.net, "i8cvs" domenico.i8cvs@tin.it, "Amsat - BBs" amsat-bb@amsat.org, "Anthony Monteiro" aa2tx@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@cox.net To: "'i8cvs'" domenico.i8cvs@tin.it; "'Amsat - BBs'" amsat-bb@amsat.org; "'Anthony Monteiro'" aa2tx@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@amsat.org [mailto:amsat-bb-bounces@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@comcast.net To: amsat-bb@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
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Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb