Christchurch and District Model Flying Club
 

 Corona 2.4 gHz DIY Module

By clive spencer

I was interested in the recent discussions regarding conversion of trannies to 2.4Ghz. I was surprised to learn that Keith was using the Corona system as I have just finished converting my Royal Evo tranny using this DIY system. I bought my kit from HobbyKing for $29 + $7.9 postage, in addition I got a 10% credit against a new purchase. With the exchange rate at the time, this totalled £21.25, which includes a nice six-channel receiver. This is not a plug & play module & involves some fine soldering to be done. The antenna wire is soldered to the sub board, which also carries the binding button & the system LED. The ppm signal wire, & the positive & negative wires have to be soldered in place either inside the tranny or in my case into a din plug. I did not want to drill holes in my nice Multiplex tranny I decided to use the trainer socket for the PPM, positive & negative lines. You will need to assemble the main board into a conveniently sized box, I used an old tobacco tin, into which must be drilled holes for the sub board mounting, the Binding button & LED. Having found these connections you will need a suitable DIN plug for the trainer socket, the wires from the module are then soldered into the correct pins on the plug. I located the module on the underside of my tranny with the aerial alongside the existing one. On the bench, the system worked fine & the binding was instantaneous, it seams to work faultlessly. I found two good web sites, which give a lot of info regarding finding the ppm, positive & earth lines on variety of radio sets. This one is useful for most sets http://users.belgacom.net/TX2TX/tx2tx/english/tx2txgb7.htm & the other for the Royal Evo/Spectrum conversion,  http://webx.dk/rc/evo/Evo-Spectrum.htm .

 I have installed the system in my Green Machine, a 40” span aerobatic model. I was not sure how to position the two receiver aerials. The instructions are very limited & refer to the antenna as being at 90 deg to one another. These aerials are about 140mm long of which 110mm are plastic covered. The question was: Does the whole 140mm have to be at 90 deg or is it only the last 30mm of uncovered part? It also did not specify the orientation, so after consulting Trevor, I placed the last 30mm of one in line with the fuzz datum & the other 90 deg vertically. This seemed to work OK so all that was left was to fly the system & see how it performed.

 I had to wait for a few days for the weather but eventually a nice calm day appeared so it was off to Howard’s for the initial flight. This posed another problem, as this system has no facility to range check it, unlike some, which have a half power range check systems. This is where you need friends? Trevor was good enough to walk the whole way down the main runway for me whilst I worked the tranny. The system seemed to be OK so I finally had run out of excuses and had to commit to the air. I had two flights with the system working perfectly which was a great relief. Would I recommend this system to anyone? If your tranny is not of the modular variety & you are a competent solderer, this is a good way to go & is very inexpensive alternative to buying a new tranny. It seems to wor k very well indeed. 

Clive  (sorry about the pictures, which got lost in translation - Ed)

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