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Old July 18th 14, 12:34 PM posted to rec.aviation.soaring
Martin Gregorie[_5_]
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Posts: 1,224
Default Anyone has experience installing KRT2 radio in single seatersailplane ?

On Fri, 18 Jul 2014 00:45:36 -0700, cruisah wrote:

Hi Martin,

both - the supplied manual on the CD (dont know the version, I have the
CD in the workshop) and the latest downloaded version (9.7) show pins 1
and 9 as NOT linked together.

OK, that's what I thought: the manual you have is wrong. The latest
version has been corrected. Pins 1 and 9 should be connected. The D-15
that came with my KRT2 has a tiny double sided PCB inside it with all
pins soldered to lands on the PCB, but this is not mentioned at all in my
manual. The PCB is soldered in so that pins 1 & 9 (ground) and 8 & 15
(positive) are connected via the PCB. The other pins are soldered to the
PCB but none of these are connected together.

First we tried using the old ATR720 wiring with KRT2-ATR720 adapter
that I ordered with the radio, but that didnt work. Then we used the new
D15 connector and wiring that came with KRT2, but we got the same result
- no speaker output. Only when we grounded pin 12 we got speaker output
(pitching and squeeling/schreeching when not receiving and
unrecognizable voice when receiving). Now we're stuck again.

My experience is a bit different to yours.

For starters I wasn't offered an adapter and so didn't use one

When I got the KRT2 I used my ATR-500's wiring harness which I adapted by
moving wires around as needed on its D-15 and adding jumpers to ground
pins for the intercom etc. The result, when I put it in the glider was
that reception was perfect, the mic was recognised (the audio bar jiggled
in response to mic input), but it only transmitted unmodulated carrier
wave. So it got sent back to Dittel via the UK agent and an internal
fault was found and repaired under warranty. Good, no quibble service.

In the meantime I noticed that my harness had pins 1 and 9 connected (as
they were for the ATR-500) but NOT as they appeared in the KRT2 manual,
and separated them.

When the radio came back it did the same as before BUT in the meantime
I'd looked inside the cover on the Dittel-supplied D-15, found the tiny
PCB and buzz-tested it, so I knew that pins 1 and 9 were connected by the
PCB. So, I soldered a jumper between them on the D-15 in my harness and
this time the radio worked perfectly and has continued to do so.

At this point I had a discussion with the agent because I wanted Dittel
to change the manual: if/when these radios get sold on in a few years
time there's a good chance that the D-15 would not go with it and the
manual as it stood would be no use at all. I thought it should say that
the supplied D-15 contained a useful PCB and that the wiring diagrams
should be changed to show that pins 1 and 9 must be connected. It turned
out that the agent (John Delafield) already knew about this wiring
discrepancy, agreed with me and was already talking to Dittel about it.

I didn't have any of the noise problems you mention, but quite possibly
there's a difference between the ATR720 and ATR-500 pinouts that could
affect that.

Apologies for this being a bit long-winded, but I've included possibly
excessive detail in case the background is is useful to you.

Would I recommend the KRT2? Yes. Now the problems are sorted its a good
radio and I'm finding its ability to monitor the standby channel
alongside the selected channel is a very useful feature.


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martin@ | Martin Gregorie
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