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Re: Drake 2880 power



Don DeGregori (W6RWN) wrote:

> This is probably an old question, but what is an easy way to power
> the Drake, if one does not have a satellite rig that puts power thru
> the cable. I know one can do the mod and apply power through a hole
> drilled in the case. Is there a cheap power inserter idea around?

The Drake is probably going to require mods in any event, and the
power feed mod appears to be relatively non-noxious, so I'm not
quite sure why you hope to avoid it.

Nevertheless, you did ask the question, and the reply above does not
answer it.   Here's what little I know on the subject.  You will need
to view the message in a fixed-width font to have any hope of being
able to actually discern what I'm trying to "draw" in crude ASCII
text characters...


                   DC Blocking Capacitor
                           ||
                           \/

IF Radio ====[coax]========)(========*=========[coax]==== Drake 2880
                                     |
                           C1        (
                                      )  <== RF Blocking Inductor
                                     (       (Sorry, couldn't figure
                                  L1  )      a better way to draw it)
                                     (
                                     |
                                    )|(  C2 - Feedthrough Capacitor
                                     |
                               +VDC Power Feed


So I suppose one could lash up a tiny perf board, a couple of RF
connectors on each end, and the requisite capacitor and inductor,
and put them into a miniature waterproof aluminum box to insert
the DC power onto the coax without affecting the IF radio.  And, of
course, if the power inserter is in the shack away from the nasty
weather, it doesn't have to be waterproof, but I imagine that an
RF tight aluminum box is still greatly preferred over anything else.

Sorry, I have no idea on the appropriate values of the components.
I guess that the inductor should probably be of the same size and
shape as the one removed from the 2880 by the power supply mod that
you want to skip.  Find a drill bit that slips nicely into the
center of the existing coil, and then wrap the same number of
turns of magnet wire around the drill bit, and use that for the
inductor.  The capacitor can probably be a 0.01 uF ceramic disc,
but don't hold me to that.  (Anyone else got a better idea?)

John Toscano, KB0ZEV
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