Hi,
Last night while tuning up into the DL to work the
3C0 (which I did, hooray), I noticed I could hear
a faint bit of rcv'd signal in the rig while connected
to the DL, not the antenna! The antenna tuner unit
was in the "Bypass" switch position to get to the DL.
However, I can also hear a faint active RF signal when
the wafer switch in the antenna tuner is just set to
Coax 2, which in my case just goes to an unused
antenna input 239 socket on the back of the tuner.
Maybe this is just 60 to 80 dB down or more
coupling between wafer switch contacts?
Top view down onto my tuner showing layout
and two wafer antenna/DL switch can be seen at:
http://www.palstarinc.com/palmain.htm
As I look at it, the DL is a sort of shielded 50 ohm
resistor connected between shield and center
conductor of about 8' if coax to the unit sitting outside
in a container of silicon oil. The container has fins to
dissipate any heat, and the DL is rated to take a
couple of kW continuous (Bird 8890 unit).
Should the unit's shielding case be grounded to
the station common ground point outside? The
DL is sitting out their just beside the ground
rod and cold water service pipe to which the
rod is also strapped with 1" wide braid.
Would a 1" wide braid to the DL case be needed,
wise, or silly??
73, Jim, KH7M
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|