[GreenKeys] [QCWA] Slightly off topic, antenna sharing.

[Richard Knoppow]

----- Original Message ----- 
From: "Jeffrey D Angus" <jdangus at att.net>
To: <greenkeys at mailman.qth.net>
Sent: Tuesday, March 26, 2013 4:42 AM
Subject: Re: [GreenKeys] [QCWA] Slightly off topic, antenna 
sharing.


> On 3/25/2013 11:41 PM, tony.podrasky wrote:
>> Well - two things:
> Robert's right, it's called a receive multi-coupler.
> And specifically it's for when the receivers you have 
> exceed the
> number of antennas available.
>
> Perhaps the confusion was in my posting this right in the 
> middle
> of the discussion about diversity reception.
>
> My personal need is that I run a repair shop for vacuum 
> tube
> radios and equipment. In addition to several bench 
> positions
> needing an antenna source, there are several working 
> radios
> up front I like to show off.
>
> With this project I don't feel like I'm running from room 
> to
> room with the one good light bulb any more.
>
> Jeff-1.0
> wa6fwi
>

     TMC made multicouplers so there may be some information 
on what is in them available. The Navy used lots of TMC 
stuff.  http://www.jptronics.org/radios/  has a section on 
TMC.
     Receiving multicouplers can be active or passive.  The 
active ones are similar to the distribution amplfiers used 
in video.  For transmitting you have a more difficult 
problem: in a receiving multicoupler one can stand 
considerable loss in the process of providing isolation 
among the ports but in a transmitting coupler the loss 
should be minimised.  Simple tuned diplexers were in use for 
decades in TV broadcasting  for coupling both visual and 
aural transmitters to the same antennas and there are 
currently many AM radio stations using multiplexers to 
couple two or more transmitters to the same antenna.  I am 
not familiar with the current design techniques but some 
searching around should find them.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com