Hi Mike,
Generally, the old Astatic D104s have a high-impedance crystal-type
mic element in them. The fact that they've been used for years says
something about their value over time, IMHO. There was also a
version that had a pre-amp that, among other things, made the D104
into a low-impedance mic, which will match most modern day
tranceivers.
I have one of the newer retro-versions which I converted to use with
a Heil element. If you've got one of the non-preamp'd D104s, then
all you'll have to do is remove the old element and replace it with
either Heil cartridge. I kept the packing material around the
original element, used some double-sided tape and installed the Heil
element on the back side of the mic head, soldered the wires and let
it go. Currently its running on the Kenwood TS2K I use in the QTH
and I get nice reports. If you're using the FT-817 at home this
looks cool, if nothing else. Unless someone's messed around with the
PTT wiring, that should be about all you have to do to get it going.
Hope that helps.
Cheers,
David/KG6IRW
--- In FT817@..., "Mike Jenkins" <k4mnj@i...> wrote:
I got a good deal on an old D-104 at a hamfest this weekend. The
D104 is the 3-wire version without the amplifier.
Can I connect this directly to the FT-817 or do I need some kind of
circuitry to match the impedance between the rigs and the
microphone?
Would it be easier to purchase a heil MC-4 element and insert this
into the D-104 head?
73 de K4MNJ
