Topband: Re: Topband: Silent Feedline for RX antennas

[i4jmy@iol.it]

Guys,

honestly, I don't think this thread is really very practical for 
amateur purposes.
Before twisting (the brain) I'd check isolation (realy, common mode, 
etc.) between transmitting port and teceiving port when TX and RX lines 
are connected or coupling between RX and TX antenna.
I believe this will be a problem of much greater order likewise preamp. 
noise and/or linearity.
Beeing the modern RX input unbalanced and an antenna balanced, 
somewhere it has to be inserted a balun and there is the point where 
I'd work about this stuff.
If your RX antenna is coupled by proximity with the TX antenna there is 
little gain in moving to the receiver end the place where to install a 
balun and/or chokes.
The ways to prevent common mode are also well known and below 2MHz I 
don't think a coax (or even a double shielded coax) can add much to the 
existing (and unavoidable) problems of very inefficient antenna, or 
with RX antennas laying all, or partially, in the near field of the 
transmitting one.
Of course any experimentation is worth, but also knowing what could be 
the final result helps to decide what to do.

73,
Mauri I4JMY