From: mycal@netronix.com (Mycal Johnson)
Newsgroups: alt.radio.pirate
Subject: Crystal, antenna, filter questions 
Distribution: world
Date: Fri, 14 Aug 92 17:41:20 GMT
Organization: Netronix, Inc.


In article <1992Aug13.145116.24594@javelin.sim.es.com> pashdown@javelin.sim.es.com writes:

  > 
  > 
  > I constructed most of the FM10 last night.  I did the suggested 75K Ohm &
  > silver-mica cap modifications.  I've got a few questions now though.
  > 
  > The 38khz crystal:  I've left off C7 and C8 in order to replace them with the
  > crystal.  However, I'm a bit skeptical as to how this works.  Do I still need
  > C7?  If not, why not?  Where do I solder the crystal in?  Why didn't they use
  > this in the original kit?  It seems like a much simpler solution and it is
  > only a dollar or so more.

        old set up       new setup
          vc               c  xtl        where c=10pf  and xtl=38khz
        |-||-|           |-||-|\|-|
        | c1 |           |        |      vc=var cap
        |-||-|           |        |      c1=cap
        |    |           |        |

I guess I shold put that in the FM-10 info sheet.  Also where did you get
your crystal?  how much did you pay?

  >
  > The brazing rod ground plane antenna: Mycal was a bit vague as to the
  > construction of this.  The only part I don't understand is what I'm supposed
  > to use for a radiator.  Will a copper brazing rod work for this as well?  If
  > so, am I supposed to have a total of 5 brazing rods rather than 4?  How do
  > these COPPER brazing rods stand up to the elements?  Also, how do I aim it?
  > I just plan on pointing the radiator at the sky.

Yes just use a brazing rod, it takes 5 brazing rods.  The radiator goes strait
up.  this is an omni-directional (all directions) antenna.  think of a donut
surrounding the radiator.
                                |
                                |     it should look like this
                              // \\

  > 
  > any variables.  I'm going to be operating on 89.5, so what are the values I
  > need on a seven element Chebyshev?  Also, I have this question about how to
  > hook it into the antenna:

use the values shown in the info sheet, they will work fine on that freq.
but it may be hard to find inductors that are exactly the same inductance,
go smaller rather than bigger.

 center rca  ---()---()---()---   ----> this goes to radiator -- center coax
   of ramsey  |    |    |    |
             ------------------   ---> braided side of coax
grnd of---  |                 |
ramsey     ---               ---
            -                 -

  > 
  > Lots of questions.  I've lost the mailing address to the FM10 list, could
  > someone send it to me?

To send a message to the mailing list, send your question, reply, comment,
or contribution to :

        fm-10@dg-rtp.dg.com

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Mycal Johnson                          _
mycal@netronix.com                    | |_ _ _         There is only one
(707)769-3309                         | | | | |__          nor-cal
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