Ron Wanttaja wrote:
Hey, Jim, I've bought a Microair T2000 to replace the bum transponder in my
Fly Baby. A couple of questions:

1. The instructions say not to install the antenna within one meter of the
unit. What's the limiting factor here? I always prefer short cable runs,
and had a nice spot picked out 15 or so inches away. What problems is a
near-by antenna introducing?

The current antenna location is precisely 4 inches below my heinie, and I'd
just as soon get it further away, thank'ee.

2. The Microair uses a DB-25 connector. I haven't soldered onto a
connector like this for about eighteen years. I'm presuming the best
approach would be to tin the wires, slide them into their locations, and
solder them in place? Should I be using shrink tubing on each connection,
too? (the connector itself has a strain relief).

3. I'm about 99.99999% sure about this, but with $1500 on the line, I'd
appreciate confirmation: When the installation manual shows the pin
assignments for the DB-25 connector, the assignments are as if I am looking
directly at the connector on the transponder...right? In other words, the
connector itself will be a mirror of this diagram. That seems to be
confirmed by the teeny teeny numbering on the DB-25 supplied with the unit.

A couple of questions to RAH in general:

Considering that I operate in an ATC environment next to never (Excluding
the temporary tower at Arlington, I've been into a controlled field three
times in the past seventeen years, and two of those were NORDO), is there
any real need to install an external Ident button? The one on the unit
itself is tiny, but I figure I can pull off a glove to press it if needed.
Adding a button complicates my connector arrangements (the unit is being
installed in a removable box).

Second, my existing encoder is a Terra AT3000. It was working at the last
check, but is anyone aware of any specific issues with this model? As long
as I'm digging things up anyway, I could just as well pay another $150 for
a new encoder, but am loath to do that without a specific reason.

(Loath, adj.: Already in trouble with the wife for spending $1500 for a
new electronics gadget.)

Ron Wanttaja
If you don't play well with soldering irons and you can get past some
folks' aversion to using 'non-certified' stuff in their experimental
airplanes, try using a 'true bidirectional' parallel printer cable made
for your windows PC.

http://www.pacificcable.com/Picture_...ataNAme=PM1-6T

shows the pinout for this cable (IEEE 1284A) on page 7. Order the length
you need, cut off the printer connector (don't cut off the db25
connector;-))& split the wires to each destination as needed. ID the
pins & number the wires to match using your ohm meter.

Several folks have put the xp ant. under the engine inside the cowl, &
Iknow of at least one person that's used one in a wheel pant successfully.

If you don't fly IFR, you won't likely need to reach the radar with it
from further than 40 miles anyway so perfect ground plane mounting isn't
that big an issue.

Charlie