Mode Zero

Thought I would share with you all another project just completed for a local club mate who has had this Horizon HS6E from new and wanted it converted using a Lemon Module and Mike's latest GTS/F3A encoder.
The earlier The red folded ali & vinyl cased D version differed in it's encoder being discrete components and switched frequencies whereas the E versions had a moulded plastic end cheeks and top and bottom and also ICs in the encoder and plug in Xtals.
MikeK tells me that the E versions were not that reliable due to strange "improvements" made by the then RCM&E electronics guru and could & would switch channels in flight! So not wishing to experience this again, Mike's latest version of the PhilG board was installed.
All went ok but a couple of challenges presented themselves in getting the Noble slide switch removed from the original circuit board and ended up needing replacement. I had a spare Futaba M series switch from a scrap Tx case which fitted perfectly and for some strange reason the aileron pot was very hard to turn which involved a strip down and easing the clearance between metal end cap and the pot wiper, and once this was sorted , the encoder calibrated fine and the installation completed with the LemonRx DSMP and the 2.4 antenna fitted nicely inside the original moulded case top cover.
So there we go another 1970s Tx put into use again for use in the 21st Century and hopefully will steer a Wolfgang Matt Superstar around the skies of Norfolk in the near future.

Nice work.

Looks like a lovely conversion and a nice clean donor transmitter. Not wanting to tempt fate, but I think you now have the most reliable Horizon HS6E ever!

The Horizon HS6D and HS6E used a ppm stream, but different to every other manufacturer, they made the sync pulse to be shorter than any of the ppm pulses (not longer) and if I remember correctly, the HS6E would reset the frame with a ridiculously short (sync) pulse, so the slightest noise and the outputs went haywire.

Mike, yes that sounds about right!

There was also something strange about the servo amps, IIRC. Most servos in those days relied on pulse stretchers to work properly - just like "analogue" servos do today - but these rely on a pretty constant frame rate. (This is why you shouldn't use standard servos on high frame-rate systems!)

Using a very short sync pulse meant that the frame rate would vary wildly depending on the length of the channel pulses. I forget how they overcame that, and I don't have one to examine, but I seem to recall something about a "padding" pulse to try and reduce the frame rate variation.

But it could just be my memory playing tricks...!

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Pete