[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Symek IFD Installation

DISCLAIMER:  These instructions worked for me.  Try them at your own risk.
I am not responsible for *anything* that happens to *any* radio equipment
you own (or might ever own) by following these instructions.  READ ALL THE

Whew, my trials and tribulations since entering the amateur satellite realm
compound...   ;-)

Bought a Symek IFD and TNC31S last week to install in my IC-821.  I got the
equipment on Tuesday and have been installing it ever since.  However, I
finally got it working last night.

Here's the story:

First, I am not an "experienced" experimenter or kit-builder.  This is the
first thing I've tried to tackle since I graduated electronics school and
SatCom school at Keesler AFB in 1992.

The first day of installation was frustratingly slow (I'm not a patient
person by nature, but I was trying very hard this day as I had a $1500 piece
of electronics that I didn't want to turn into a $1500 "lump" of
electronics).  I read the instructions as best I could (the instructions are
*excellent*) and re-read and re-re-read.  MAKE SURE YOU LOCATE A LIT
work on the radio.  I first removed C93 which apparently, in this day and
age of SMD, is not labeled.  As luck would have it, Symek has, again, done
an excellent job describing its location.  BTW, the instructions say that
the coax on the 70cm board cannot be removed.  Icom must have made a change,
because mine were easily removed giving easy access to the bottom of the
board.  Also, C93 didn't appear to be held in place by any sort of
heat-resistant glue.

I then prepaired the ptfe coax.  I cut them to 15cm each (Symek says these
lengths aren't critical, but you want some slack to connect to the IFD
board).  Strip 25mm off each end of the ptfe, then trim the shield back at
least 10mm.  I used a small jeweler's screwdriver and meticulously unwrapped
each individual shield wrap down to the outside insulation that is
remaining.  I carefully stripped back about 3mm (about 5mm on the side to
the IFD) of the dielectric and tinned both the center conductor and shield.
Prepare both ends of both cables before you go any further with anything.
Doing this small work using the jeweler's magnifying glass, I had to get up
and walk around for a while after preparing each end due to eye strain.
Once the coax is prepared, you're ready to install them in place of C93.
Follow the instructions verbatim for this.  Trim the shield short enough
that it doesn't come in contact with anything - I trimmed each to about the
lengt of wire sticking out of the solder pad and soldered in place.  Check
your grounds with an ohmmeter.

Once you are done with the RF board portion of the installation, you can
replace it taking care not to break your solder connections you just made.
Again, check with an ohmmeter to make sure you haven't shorted or opened
anything.  Now you are ready for soldering to the IFD board.  I recommend
that you mount the IFD board in your transceiver before doing this.  I
mounted mine using the dual-sided sticky pads that come with telephone
jacks.  I used two because the wires stuck thru from the solder pads on the
first sticky pad.  With the front of the radio facing you and the top facing
up, there is a blank spot just below and to the right of the RF board (it is
right behind the front panel).  I mounted my IFD board vertically there.  It
will be just in front of the PA fan and to the left of it.  Start your
solder connections to the IFD board.  The instructions include a layout
diagram of the board.  The RF-IN, RF-OUT, DATA-OUT are labeled around the
board in the diagram; all these connections are the *outside* pins.  The
inside pins are all ground.  Ground your RF-IN and RF-OUT.  I tried
grounding DATA-OUT and I got noise in my rcv when I turned the tuning dial;
however, this was done in an effort to provide a return for the IFD board
and was before I grounded the RF-IN and RF-OUT.  Don't let that last
statement confuse you, just don't connect the shield from your DATA-OUT
connection.  I got 12VDC from the front panel.  If you look at the front
panel circuit board on the left, you'll see a red wire and a black wire.
These come from the main power switch.  Solder a wire to the 12V wire (mine
was red) and solder the other end to the 12V on the IFD board.  Use
tie-wraps to secure.

The last connection was to pin 8 of the ACC connector.  Follow the
instructions for this.  I actually used a piece of RG-58 for this as I was
out of ptfe coax.  I stripped back enough insulation and did the shield as I
mentioned above.  Tin the sheild and heat-shrink it.  I put a DC lug (put it
on *before* the heat-shrink) on it and connected to the chassis screw just
to the left of the ACC connector with the radio's bottom facing up and the
front facing you.  Route your coax in such a way as it will not interfere
with replacement of the bottom cover.  At the IFD end of this coax, strip
back the insulation (about 40mm) and cut the shield off.  Connect the center
conductor to the DATA-OUT connection and cover with heat shrink.

That's it!  Replace all your covers and try your radio out.  If everything
is working, you should be able to hear local repeaters and the satellites as
they pass overhead.

GL es 73,

Joel B. Black, K2SAT
AMSAT Local Area Coordinator
AO-10, AO-27, FO-20, FO-29, SO-35, UO-14
KO-25, TO-31, UO-22

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org