I use a 600 foot long run of CATV coax to power a remote pre-amp at the
DHDL-s, delivering +12V/100 mA via the central conductor (return via the
shield). Prior to installing the F plugs I spray the cleaned and prepped
ends of the coax with DeOxIt. I also spray the inside of the female F
connectors. I add a small amount of SS-30 grease to the thread of the each F
connector, tighten the connector using a small wrench (!) and tape the
outside of each mated F connector.
So far, no no noise, micro-arching or other.
Further, I believe that the DC current keeps the contacts vetted, which
makes them more reliable.
73,
George,
C6AGU/AA7JV
On Tue, 6 Oct 2020 04:44:51 +0000 (UTC)
Dennis W0JX via Topband <topband@contesting.com> wrote:
Regarding the issue of voltage over coax to power the preamps used at the base
of short verticals, Lee, K7TJR, developed an alternative power feed system for
his new SMD preamps using a separate RG6 coax. Apparently, K3LR is using such
an approach to avoid sending voltage down the coax in his 8 element HiZ array
at his contest station.
DXE has begun selling the new version 2 preamps but the description in their
catalog does not mention this separate power feed system. The older HiZ
preamps, and the YCCC preamps, can probably be modified to the voltage with a
separate wire from the combiner box to each vertical antenna preamp.
One question I have with this approach is whether an external power wire would
also need a common mode choke on it. Perhaps Lee could offer some opinions on
this alternative power approach.
73, Dennis W0JXMilan, OH
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