[amsat-bb] Re: Diplexer

[Bob- W7LRD]

 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@ 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@ 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@ 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 at 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 
> 
> i8CVS Domenico 
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