[Antennas] DC voltage on coax

[Bob Nielsen]

On Thu, Nov 04, 2004 at 10:30:30AM -0500, William Lambing wrote:
> There are 2 series capacitors.  If you will they are connected
> together.  The RFC injects DC voltage at one end and the other RFC
> takes the voltage out at the other end.  There is no DC voltage at
> either the radio or antenna end.  The voltage is present only on the
> coax between the capacitors.  This keeps DC off of the radio and
> antenna.
> 
> We used 1mh chokes and .01mf caps.  Our frequency range was 6.9 to
> 7.3mc (before MHz) and it worked.
> 
> I think even some of the ARRL Handbooks had a similar item shown.
> 
> 73
> 
> Bill, W0LPQ

But what you showed had the DC connected to the radio and isolated from 
the relay:

ANT-----||----------------------||-------radio
                 |                        |
                 |                        |
               RFC                     RFC
                 |                        |
                 |                        |
               Relay                   +Volts
                coil


The capacitor should be between the radio and the voltage source:


ANT-----||------------------------------------||----radio
                 |                        |
                 |                        |
               RFC                     RFC
                 |                        |
                 |                        |
               Relay                   +Volts
                coil

73, Bob N7XY